GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Tim F on April 19, 2022, 07:47:41 PM
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Air venturia avenger 25 JSB 25.39, will group 3 shots in 1" or less at a 100 yards, but consistently has 2 flyers out of 5 shots. I am trying to figure out what is causing the flyers. I have tried 2 different scopes, 3 different pellets, the same results. Wondering if the regulator could be the issue. Regulator is set at 2100 psi, fill to 3300 psi. All pellets out of the same tin. Any insight would be appreciated.
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Air venturia avenger 25 JSB 25.39, will group 3 shots in 1" or less at a 100 yards, but consistently has 2 flyers out of 5 shots. I am trying to figure out what is causing the flyers. I have tried 2 different scopes, 3 different pellets, the same results. Wondering if the regulator could be the issue. Regulator is set at 2100 psi, fill to 3300 psi. All pellets out of the same tin. Any insight would be appreciated.
Are the fliers all ending up in the same area, like they are grouping together? Or are they random?
100 yards gives alot of time in flight to be affected by wind and even pellet deformation. Most guys shoot slugs that distance to counter those issues. Have you tried shooting closer to see how it groups. I would try 30 yards, then 50, to see if it repeats itself.
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Tim, My 25 Avenger shoots like yours at 100yds also. My goal is to put them all into 1moa at that distance but like yours two out of five go off course. I’ve done a lot of experimenting but so far my best efforts haven’t found the problem. The shroud makes the poi sensitive to change and these rifles may be sensitive to bbl harmonics. I’m thinking of adding a second internal shroud centering/Oring between the factory one and the muzzle and testing it in different locations. Different suppressors I use don’t seem to make much of a difference and the factory bbl band seems adequate. I haven’t had the bbl off yet for lapping but when I do I will pay special attention to the chamber area. I plan to experiment with a short (1/16”) freebore throat and remove any rifling up to that point. This darn rifle already shoots better than it should and I think it has more to give.
Mine is a gen1 with the shroud held in place by one screw into a plastic centering block at the breech and Im thinking of replacing it with the aftermarket aluminum one offered on eBay. A FFP scope is helpful at 100yds and further.
Tom
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Matt Dubber has a video about the Avenger. He mentions something about flyers and how the stock endcap on the shroud was contributing to the flyers issue. He switched to the Donnly Fl end cap - problem solved.
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Matt Duber is great and I have watched many of his vidios. Mine has the DonnyFL extended suppressor adapter on it and after some fiddling around with it was able to make it work well. But the extender tube that slides 1/2” over the muzzle inside the shroud was too sloppy and on inspection had ‘rattled’ a bright wear ring telling me that stuff was going on there. I added a wrap of electrical tape at that point on the bb. and problem solved. But the flyer problem still remains unchanged.
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Matt Duber is great and I have watched many of his vidios. Mine has the DonnyFL extended suppressor adapter on it and after some fiddling around with it was able to make it work well. But the extender tube that slides 1/2” over the muzzle inside the shroud was too sloppy and on inspection had ‘rattled’ a bright wear ring telling me that stuff was going on there. I added a wrap of electrical tape at that point on the bb. and problem solved. But the flyer problem still remains unchanged.
I see. There are soooo many variables
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Study the wind more...it does not take much at 100 yards...even in a 90 degree 5 mph wind...
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Thanks crazyhorse,
I can’t speak for Tims results but my testing for extreme accuracy is only done in still air. My range is 55yds, 80yds, and 110yds due to the layout of my property. Short story is that the flyers occur with the most accurate ammo but always opens up a sub moa group. There is a reason I haven’t found yet but it’s not wind.
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Thanks for all the insight. The flyers open the group up to 1-3/4 to about 2-1/2 inches. I haven't tried any slugs, that may be something to look at. I have tried the Donnly FL extended with and without the SUMO, same results. I opened up the barrel band around the shroud because it was pulling the shroud down and causing bad barrel droop. Glass beaded the pic rail that the barrel band is attached to because of poi shift. I added a second (aftermarket) band about 1-1/2" from the end of the muzzle, I might try moving it around to see if that has any effect. I had the a vortec 6-24x50 FFP on it for testing, same issue. I see the same issue at 35 yards, you can cover a 5 shot group with your thumb nail, usually 3 shots in 1 hole and the other 2 open the group up a tad. Still chasing the rabbit.
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Shooting from the magazine or single shot tray?
Sorted pellets or straight from the tin?
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Using single shot tray and straight from the tin. Look at each pellet to make sure there aren't any obvious dents or dings.
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I've seen similar fliers too -- not at that extreme range -- I tend to assume I flinched or jerked the trigger or something -- maybe it's not me after all. No sorting, straight from tin, obvious duds not used.
One thing I've noticed, on .177 in particular, single-loading with tray, is sometimes the probe does not look exactly centered, and may be pushing on the edge of the skirt, rather than precisely centered co-axially. I load gently as possible, but that could still deform one edge of the skirt and cause them to fly. I have not investigated -- in fact this thread just reminded me of what I thought I might be seeing. May not be an issue with the larger calibers...
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Could be pellet head size...
Might look into that...
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I think supporting the end of the barrel, like with a DonnyFL adapter, is a good idea. The shroud spacer is only about 2/3 the way to the muzzle leaving a lot of the barrel unsupported and the other end of the barrel is supported by plastic. I used to use a DonnyFL but went to a printed suppressor that also supports the barrel - or at least limits movement.
I struggle with shooting groups as small as I want will all three of my airguns. I get 3 shots groups as small as 1/8 from them at 25 yards but I also get an occasional 3/4 inch group. Not sure all the variables but I think the biggest one is me.
Lately I've been shooting the symbols on playing cards at 25 yards. They are around 3/8 inch. My best card so far out of the first deck is a 7 with no misses from my 25 caliber Avenger. It and my 25 caliber P35 have an advantage over my 22 caliber Prod in the size of the hole. Some of the near misses with the Prod would have been hits with one of the 25s. I see fliers shooting groups sometimes with my Avenger but if it can put 7 shots in a row within less than 1/4 inch of my aiming point it's probably capable of smaller groups than I normally shoot.
FX 25.4s seem to shoot a little better than JSB 25.39s from mine.
Jim
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Did some more testing yesterday. Removed the aftermarket barrel band and the poi moved up 2" and group size increased a little, next removed the shroud all together poi moved up 4-3/4" and to the left 2". Checked barrel screws, all 3 were snug. Seems like the shroud is putting a lot of pressure on the barrel. Not sure how to tell which is out of alignment, any thoughts.
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Tim,
I’m with you and think the problem lies with the shroud putting unwanted pressure on the bbl. I’m having a similar problem with my Akela after adding a bbl band (this gun really needs one). Testing with it this afternoon confirmed it as the gun was accurate before I added the band and now it’s not. Sliding the bbl band to different locations makes a difference in group size and poi. I also shot the Avenger 25cal today but just for fun and didn’t do any testing. Todays targets were .38special empty cases @55yds and it blows right through them if you can find them afterwards.
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Thanks Tom for the confirmation, I will try moving the aftermarket barrel band around and see what kind of results I get.
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You could try polishing your bore with some JB Bore Bright and a bore mop with a cleaning rod from the breech end with the barrel removed. I have had several powder burners and air rifles that would throw fliers and it helped a lot. There are several YouTube videos on how to do this. A lot of the barrels that are made in China are pretty rough. Polishing the bore helps to smooth it out some.
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The bore of my .22 Avenger was one of the roughest I have ever encountered. It responded well to a little attention with an abrasive compound.
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I constantly have to remind myself that lead pellets are not precision projectiles.
Well, at least it's a good excuse... ;)
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I, too, am experiencing this issue with the .25 avenger (but not my other $300 pcp). I just accepted it (flyers) was the price to be paid for shooting a pcp with this much stuff at this low a price after watching tedsholdover's review of it.
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Has anyone with this flyer problem had a known good shooter try our same gun.All this would do is elimnate one more big variable.I used to teach hunter safety and had this work to prove flinchers, so will an empty chamber. We all can think pretty highly of ourselves, and thats is good , it's human nature.
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I've been checking the first shot placement from my 25 Avenger for the last several days. For three days in a row I missed the playing card symbol with my first shot, typically by about 1/4 inch, but today I hit it. A difference was I shot my Prod first (fine tuning the sight in after a retune) and then shot my Avenger. I have also been checking the first shot velocity. Today there was no difference, the biggest difference I have seen is about 10 fps.
Each time I missed, the next two hit. But this is starting to look like another case where it is the shooter (me) instead of my gun. But I need to warm up again with another gun and then try the Avenger to see if I can repeat todays result.
I've also tried playing cards right away with my other two guns and not had any issue with the first shot - so I'm not sure. Maybe it occasionally mis-places the first shot by a bit. Not enough to miss a squirrels head.
But my best card out of my 3 guns was shot with my Avenger. It is an accurate gun.
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Jim can you tell what you have your reg and hammer spring set at. I tried weighting my pellets and shot only the ones that had a weight 25.4 +/- for today's shoot at 100 yards. It didn't make any difference, same issue with two flyers. Another variable eliminated. I detuned it this afternoon back down to around 1600 on the reg and 2 hs, time for the pesting (35 yards) to begin. I am beginning to think the avenger isn't going to make for a 100 yard pesting . We have lots of prairie dogs here in South Colorado, my son says I just need to move the pb.
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He's probally right.
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Did some more testing yesterday. Removed the aftermarket barrel band and the poi moved up 2" and group size increased a little, next removed the shroud all together poi moved up 4-3/4" and to the left 2". Checked barrel screws, all 3 were snug. Seems like the shroud is putting a lot of pressure on the barrel. Not sure how to tell which is out of alignment, any thoughts.
Are you using the stock rear mounting bushing? It is a wildcard as far as variables is concerned. It is an out of round mounting surface made from a material that will likely change hardness with the ambient temperature. Next it is secured to the BBL with one set screw which will push the surrounding plastic wall away from the O.D. of the Barrel where the end of the set screw contacts the barrel. This is putting force against the barrel and the inside of the shroud away from center.
Many here know that putting too much torque on similar screws that hold a barrel in a receiver block can throw accuracy off. They force the barrel off center and can even warp the straightness of the barrel. Go to a solid metal, dead round, snug fitting after market mounting bushing. Keep everything as straight and concentric as possible.
Floating barrels especially when harmonics are balanced can be supremely accurate but shifting POI is a common problem with them.
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Spin, it does have the original rear mounting bushing. This one is threaded and the shroud screws on to it. I haven't seen any aftermarket metal ones that are threaded. Thanks for your insight. May require gun with no plastic for long distance pesting.
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Its quite normal look issue from gun. Most cases its shooter.
Have you ever shoot with anything like 100yd 5 shot sub moa groups with five times a row? Im not. Even now 2 times. Couple days ago it was close. From 10 group 4 was sub moa..
There is soo much chances hold, position, bipods, cheak rest, scope, ammo, rear bag, table, paralax, wind. Smallest breeze can take pellet or 60gr slug one- two inch off.
Check where go reticle goes after shot. 10 12 or 2 a clock. Scope cam would help with that. It will tell your technique a lot.
I have used Mantis shooting tracker when training pistol shooting. Have to test some day is it suitable also Br shooting
One more tip. Shoot these 30yd scores for training. When you get 200/200 x20 you know its quite perfect everything
https://www.gatewaytoairguns.org/GTA/index.php?topic=114701.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=114701.0)
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Spin, it does have the original rear mounting bushing. This one is threaded and the shroud screws on to it. I haven't seen any aftermarket metal ones that are threaded. Thanks for your insight. May require gun with no plastic for long distance pesting.
Take a look at the A.E. Swede (known for their magazines) site. I think I saw threaded all metal ones on there. I would be inclined
to go with a precision turned metal mount. I'm a bit leery about thread fit and concentricity if the OEM part is still cast plastic.
I've checked over the old style mounts with precision V blocks and the plastic bushing that is positioned around midway point of the barrel inside the barrel shroud. The OD on that isn't terribly consistent either. I wonder if this choice of materials isn't for dampening of vibrations
as well as the more obvious purposes. I've been thinking about using some thing similar (with adequate channels lengthwise to allow air passage while seriously dampening harmonics rather than f@#ting around with counter weights and such. I really think it's the way to go.
From what I've seen an Avenger with a fully deadened barrel was extremely accurate and "Consistent" as well.
https://www.youtube.com/watch?v=UN6bSMzV3s0 (https://www.youtube.com/watch?v=UN6bSMzV3s0)
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Thanks for the information, do you know what he used to deaden the barrel. I will check with AE Swede on the metal bushing.
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Thanks for the information, do you know what he used to deaden the barrel. I will check with AE Swede on the metal bushing.
They used sand inside the shroud. This is something I would Not Do nor recommend anybody else do. As a machinist (retired)
hollow core bushings that could filled with very fine lead shot, fine glass or metal beads, and capped off and slid down into positions along the barrel and snugged up in place with opposing set screws 4 to 6 of these vibration dampening bushings should do nicely.
The outside of the barrel should serve as the inner wall of these shot compartments as you want contact with the shot inside.
This is how De-Vibration boring bars are fundamentally designed and made and should tame greatly or eliminate harmonics and improve accuracy. You could make one long inner tube with 1 to several shot compartments. You want the shot to be a little loose inside too.
Old Timer machinists learned how to stop chatter or singing (tight vibration = harmonics) by lightly holding a ballpeen hammer, brass round stock, etc. on top of the workpiece while turning long and less ridged round stock on an engine lathe to stop the offending vibration.
With the advent of after market Bottle adapters. ( use a ninja to bring down fill pressure and the one built into the gun to fine tune minor final; adjustment and you would have the same system in essence as the FX Mustang and Impact and with a 480 carbon fiber bottle and 1 to 2 of the now available power plenums and the Avenger Will Really perform and Oh the distance capabilities you would have!
P.S. A.E. Swede does have the screw type rear mount bushings.
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Tim and Jerry,
I’m still following this with my Avenger 25cal and dealing with the same problem. Todays testing and shroud inspection has confirmed that the poi problem lies with bbl/shroud alignment and stability. The muzzle when viewed under bright light inside the shroud moves where ever the shroud is moved to. Also, the factory bbl band placed midway down the shroud (at least on mine) only puts pressure on up and down movement and allows much movement side to side. All the while the muzzle remains 4” from the tip of the shroud free floating. It’s clear to me that I need to buy the aftermarket aluminum shroud mounting piece as my plastic one has been stripped, re threaded, and stripped again. I think your is the later threaded mount.
Too dark to test now but I have put a paper shim under the factory bbl band to eliminate horizontal movement of the shroud and installed a centering muzzle stripper and replaced the moderator that I am using. This set up puts pressure on the muzzle and some have said that you can’t do this, but other testing with the DonnyFL extended adapter has worked under pressure with a different moderator. The only problem I see is too much pressure on the shroud breech screw as the shroud wants to creep forward.
I’ll let you know if this works.
Tom
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Study the wind more...it does not take much at 100 yards...even in a 90 degree 5 mph wind...
I would agree totally. Also to do really well with an airgun at 100 it “seems” from everything I “watch” and “read” (notice no personal experience so don’t listen to me 🤣) that you have to spend some coin. The avenger is a cheap piece and I think consistent 100 yard groups free of fliers might be a bit of a high bar for it.
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Tim, My 25 Avenger shoots like yours at 100yds also. My goal is to put them all into 1moa at that distance but like yours two out of five go off course. I’ve done a lot of experimenting but so far my best efforts haven’t found the problem. The shroud makes the poi sensitive to change and these rifles may be sensitive to bbl harmonics. I’m thinking of adding a second internal shroud centering/Oring between the factory one and the muzzle and testing it in different locations. Different suppressors I use don’t seem to make much of a difference and the factory bbl band seems adequate. I haven’t had the bbl off yet for lapping but when I do I will pay special attention to the chamber area. I plan to experiment with a short (1/16”) freebore throat and remove any rifling up to that point. This darn rifle already shoots better than it should and I think it has more to give.
Mine is a gen1 with the shroud held in place by one screw into a plastic centering block at the breech and Im thinking of replacing it with the aftermarket aluminum one offered on eBay. A FFP scope is helpful at 100yds and further.
Tom
Unless you have a later manufactured shroud you will need to gets a new shroud that is threaded at BOTH ends The older original rifles are only threaded at the muzzle. With such thin walled tubing as these shrouds threading the other end, even in a very well equipped shop is no easy win. It would likely require turning and or polishing mild steel plugs with a nice "size for size fit" or Very Light Press fit in the shrouds bore to allow secure chucking and rigidity of each end. also drill and tap at least one if not both ends of these plugs so you can employ a slap hammer (draw hammer) to remove them.
As concentricity is the goal a live bearing steady rest is likely the best setup. You can plug the end and chuck it in your, bored to exact size, soft jaws and making sure you have the plug pushed in deep enough to allow room for I.D thread tooling, you could go with that faster, easier setup and forego the steady rest but you have to be "dang" certain you Do Not turn on that lathe at high rotational speed or it will whip that tubing around harder than Roy Rodgers on Trigger, inside the chuck and spindle, bending the tubing beyond saving.
Better most likely to snag a new shroud as fit and concentricity of the threads is very important. It would be Great if a after market shop would also machine replacement bushings to replace the soft plastic ones used mounted in approx. the center of the bbl length as well.
Turn their O.D.s about .010 to .012 under the shroud bore dia. and cut appropriate sized O-ring groves for rings that with put .002 to .003 squeeze per side when pushed into the bore of the shroud. Enough give while adding support and keeping things straight and concentric.
If air flow is a factor concentric and evenly spaced holes running through lengthwise should take care of it. The dynamics of air movement in the shroud/stripper, moderator" is beyond me so more knowledgeable than me can figure that out. The Groove dimensions in the "in shroud
moderator and the supplied O-rings are a perfect fit and I know that Moderator is still available online. I've seen it recently and I'm guessing it wouldn't be too hard to get the specs on them.
While I'm sure addressing these weaknesses in the design, the build of the Avenger, effect accuracy and consistency the peculiar shifting of POI seems too common and routine to not have roots in the regulation and performance of the air pressure propelling the round what ever the type, size or weight but basic straightness and concentricity really should be taken care of first. Eliminating excess vibration I think is also
a step in the right direction.
retiring from the soapbox now (sorry, I've really got to get out more often)
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Jerry,
I appreciate your input about centering and locking these shrouds in place and that is the direction I am proceeding in. You seem to have more info than I do so let me ask your opinion of what I should do. I planned to order an aluminum shroud mount from AE Swede that mounts the shroud to the breech with one screw but then ad two more securing screws for stability. You mention the possibility of buying a ‘threaded’ aluminum shroud mount and replacing the shroud with a double ended threaded after market shroud. I haven't found this offered and maybe you can steer me in the right direction.
Thanks,
Tom
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Jerry,
I appreciate your input about centering and locking these shrouds in place and that is the direction I am proceeding in. You seem to have more info than I do so let me ask your opinion of what I should do. I planned to order an aluminum shroud mount from AE Swede that mounts the shroud to the breech with one screw but then ad two more securing screws for stability. You mention the possibility of buying a ‘threaded’ aluminum shroud mount and replacing the shroud with a double ended threaded after market shroud. I haven't found this offered and maybe you can steer me in the right direction.
Thanks,
Tom
Sure Tom, A.E.Swede makes and stocks them. OK now I have 2 Avengers both are older manufactured ones as they both have the single round head screw that secures the shroud to the mounting bushing. These are what I bought and installed. The .22 cal has one that's a bit sloppy fitting so I used heavy duty Alum. foil and shimmed it for a tighter fit which worked out OK. Perhaps still .0015 to .001 clearance but that still "close enough for the girls we go out with"
OK now as I I've been led to believe the newer Avengers have I.D. threads identical to those at the other end so apparently the shroud now screws on to these threads on the mounting bushing and the bushing slides down over the barrel and is locked in place flush against the face of the receiver block with a set screw/ screws?. OK, fine I can picture how that would work.
While snooping around looking for an old style alum mounting bushing I spotted a picture on their site what sure enough looks like a new style alum. mtg. bushing. A threaded one. Here it is, link; https://aeswede.com/collections/see-catalog-menu-for-all-on-my-currents-items/products/airventuri-avenger-rear-shroud-mount-cnc-7075-high-strength-aluminum
That's great and sooner or later I'll be looking to go with the newer threaded bushings myself but me, you, or anybody with an older Avenger will have to get a new shroud that is threaded on both ends of the bore or have the ability to cut the threads in one end themselves or have it done by someone else. The manufacturer is set up for this and likely buying a new shroud might be the wisest choice.
The rest of my previous babble concerned replacing the soft rubber barrel spacer/support with ones that would not only help keep the barrel inline and concentric but also deaden barrel vibration also and increase accuracy.
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Tom and Jerry, I did order the threaded bushing from AE Swede as my shroud is threaded. The plastic one has a small alinement pin that lines up on the receiver, ther is about a 1/32" gap between the bushing and the receiver. This along with the single set screw may add more variables. When I get the new bushing I will do some more test. I also need to check the shroud tubing to see if it is a consistent ID all the way along it. I will keep you posted as the results of testing.
Thanks again for all of the support.
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So shooting my 25cal Avenger today its confirmed that the shroud and mount is the problem. A E Swede only offers the threaded version of the shroud mount and doesn't answer my email from his eBay site, his website has no way to contact other than to order. I think the best way forward is to replace the shroud with a newer threaded one and upgrade to the A E Swede threaded aluminum mount but hey…. Air Venturi website doesn’t offer parts for sale and I don’t find any other website that offers factory parts for sale either. Since its not a warranty issue just how can you ‘buy’ factory replacement parts? This should be a simple straight forward process but is turning into a Catch 22 situation. What..
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It is a good idea to sort pellets by weight. I’ve picked up from my own measurements that generally pellets will have 3 to 5 weight groups in a tin varying by tenths of a grain. Slugs typically may have 2 weight groups varying by hundredths of a grain. Pellets head and skirt sizes from the same tin don’t vary much and slug diameters don’t vary hardly at all. I’m not very good at shooting yet, but I did find that pellets of the same weight made much closer groups. I also ran across advice to wash pellets in dishwashing detergent, dry them, and then coat with a bullet lube wax compound. I haven’t quantified washing and lubing yet for significance on spread or velocity.
I’ve ordered a bullpup avenger! Can’t wait to try out my first pcp. I’ve been shooting a Gamo swarm maxxim gen 2 .22 cal.
Best wishes,
Dow
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Tom, it is difficult to find parts for the avenger. Look at "Bison air guns", they show the unthreaded bushing, shows to be out of stock now but, you may check with them and see when you may get one. I have been disappointed in the air venturia as they said that parts would be available, so far, not so. Hope this helps. My next pcp will need parts available when I purchase it.
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Tom, I just went to "Bison air guns" and they show the "avenger rear shroud boss" in stock. Hope this helps.
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Thanks, just ordered it.
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Thanks, just ordered it.
I was looking around to Tom If I couldn't find one I was going to spec one of mine out so there would be a drawing and dimensions
that could be wacked out by somebody with the resources and desire.
Another thing that struck my mind is that the picture on the Bison site showed the bushing slid on the barrel reversed from the way
it mounts. The larger dia. shoulder should mount flush against the face of the receiver and the smaller dia. fits into the shroud as does the o-ring.
If the tapped hole for the mounting set screw isn't drilled and tapped through the opposite side and you can drill and then tap it all the way past the opposite side - do it. Use the existing thread to guide the tap. De-burr and get a second set screw(make sure the seat against the barrel with the allen socket end completely below the outside of the mounting boss so it doesn't interfere with the shroud when you slide it on. Tighten slowly trying to keep even torque on each side. Don't bear down too hard. You don't want to scar up the O.D. of the barrel
Check for fit before finally fitting. if it's too loose cut some from aluminum foil. Heavy duty is a bit thicker should you need it. You need to leave a gap where the small button head screw matches the matching tapped hole in the side of the boss. Cleaning and drying boss and barrel and using a small drop of super glue under the bottom of each end of the shim can make things go a lot smoother. Aluminum foil is cheap and a razor blade scrapes off gluing mistakes easily. (if there's a .001 - .002 clearance - don't sweat it.
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Jerry, thanks for the tips. I will keep these in mind when I install the one from ae swede, haven't received it yet. I think it has a set screw on both sides.
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The Bison product aluminum replacement shroud attachment works fine and I fired it today. However the mounting screw hole to attach the shroud was drilled too far forward to allow the shroud to be pulled over the O ring by 1/4”. Easy fix as I will just drill another hole in the shroud to allow proper fitment closer to the breech. Good product otherwise. A step in the right direction.
Tom
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Tom thanks for the update. I am glad you were able to correct the issue. I receive mine from ae swede but, haven't been able to test it as we have been having 25 - 30 mph winds with gust above 40, as soon as we have a break I will be testing the change.
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Todays testing took me backwards just a little but I had to satisfy myself that the ammo isn’t the flyer problem. So I retested some that were less accurate and they still were. Returning to what this 25cal Avenger likes best, 25.39gr. and 30.86gr. in both H&N and JSB, it shot well at 80yds but after four nearly touching shots number five always went somewhere else. Next step will be removing the bbl and lapping and polishing it as the bores on these, and many pcp rifles, are pretty sloppy and truth be known shoot better than they should. I’m convinced that while top quality commercial pellets are pretty darn good they have a limit and are susceptible to the slightest variance, especially noticeable beyond 40yds.
So I just ordered a batch of slugs from H&N and Neilson Specialty Ammo in .249 and various weights. After I finish with the bore lapping and polish I will have a lot of testing to do and results will follow. Let’s hear how you are doing with the flyer problem.
Tom
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Tom, I installed the new rear barrel bushing. All went well with the installation, had a break in the wind this morning and took a few shots at 25 and 35 yards. I was able to put 5 shots in each group, measured 3/8", had to stop at this point as the high wind had returned. This is an improvement as before the groups were more like strings. The next break in the wind I will go to the range and stretch it out to 50 and 100 yards. The flyers become apparent at 100. Will be interesting to see if polishing the barrel helps, if so, I may give that a try. Thanks for the update.
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Went to the range this morning, shot well at 35 yards, 1 ragged hole, less than 3/8". At 50 yards group opened up to 11/4". I think my tune is to low. Regulator was set at 1500 and hs 2 in. Reset Regulator to 2100 hs still at 2 in, will see how this works next time I have range time.
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Like a bulldog I won’t let go of this flyer problem until I at least achieve average rimfire accuracy. Not only with my 25cal Avenger but with others I am working with and today it was my Cayden 22cal. Same problem at 75yds, four of five shot well and then one has a mind of it’s own. Only when I switched to slugs was there an improvement by 1/2” of grouping, and while the groups could be better there were no flyers. Avenger 25cal slug testing to come soon after my order of slugs arrive. So far my impressions are that slugs are more forgiving than pellets beyond 50yds just due to their nature and ballistic coefficient. Pellet flaws become apparent at this range and their performance just gets worse the farther you shoot. I have shot some enviable 85yd groups with 25cal pellets but they aren't repeatable. The imported bbls. on these lower priced pcp rifles do not match the quality usually found in decent rimfire rifles and I am now equipped to lap and polish these to get the most out of them and I think the answer is in the bore.
Tom
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Tom I think that for the performance you are looking for you might do yourself a world of good to settle in, set up a crony and start adjusting the hammer spring (in Both directions) incrementally by 1/8 turns. Tuning for best results can be a matter as small as that simple 1/8th turn
either up or down and it can make a BIG difference in consistency and accuracy. You can adjust the hammer spring tension up or down without gassing off the rifle. Make your adjustment After shooting and before re-cocking the action. Write down your settings and results including cal. make, model, and weight.
Going into slugs you want to kick up velocities into the high 800's to mid 900's. They will function below that yes, but you won't get full capability. Also their flight might not fully stabilize at moderate distances but self correct father down range.
And be careful! Air rifle slugs generally have much, much higher sectional density and higher B.C. and you have to be cautious and aware that slug will travel much farther and with more energy than a Diablo Pellet, through the air or bouncing off the ground or a object. A bit more caution than usual is called for.
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Tom it seems to me that there is an instability in pellets as they get further out. I am going to order slugs from avs and get a chronograph and follow Spins lead. PD season starts here in about a month and would like to use the avenger.
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Whoever had the reg set at 1500……yes that is much too low on a 25 cal. Mine is 2100-2200 and I think on the absolute lower end of the useable range. Mine is super accurate out to 50 and I know they are capable but I think 75 and 100 consistently is much to expect from it.
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Mine is at 2300 and does a great job at 50 for 6 8 shot mags from 4300.
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With long range accuracy being my goal with the 25cal Avenger my testing has led me to setting the reg @3000psi and I fill to 4000psi and get 4 mags per fill. I learned to back off the hammer spring by 1 3/4 turns after recording hammer bounce on the db meter and that corrected it. This setting drives a 21gr pellet @946fps through my chronograph and the heavier ones a little slower. While I plan on losing some velocity with slugs what I give up in speed should be worth it past 50yds with better BC, less velocity fall off at long distance compared to lighter pellets, and better wind bucking ability.
It looks to me that it all comes back to the bore for fine consistent accuracy. I haven’t received my order for slugs yet but will probably play around with pellets this afternoon. I’ll report anything that looks promising.
Tom
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Well this was interesting at 75yds.. I tested two pellets, H&N 27.47gr, and JSB 25.39gr. The H&N which had shot well previously at 50yds only gave acceptable hunting accuracy at 75yds and nothing to brag about. By the time I got to the JSB’s the reg pressure had dropped to 2700psi (reg creep) and these shot more accurately.
But here’s the strange part, the first group of JSB’s strung out horizontally only, and the second group strung out vertically only. One group measured 1.560”H, and the next measured 0.825”V. But both groups only measured, get this; .014” and .075 but in the opposite direction of each other. Huh?
I believe in cause and effect so it seems I'm still looking for the cause. Before anymore testing with reg pressure I plan to ‘properly’ lap the bbl on this and a Cayden rifle I am also working with and then do a comparison with pellets and slugs. The goal has always been consistent long range accuracy from 75yds and beyond.
In the meantime let’s hear what works for you.
Tom
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Tom, these are very interesting results. I hand pump at this point, so only fill to 33-3400 psi. I have noticed at times that it seems my accuracy is better at lower pressure, 26-2800 psi. I will have to pay closer attention to this as I test in the future. I have had these vertical and horizontal strings as you described from time to time. What type of rod are you going to use to polish your bore. I have some jb polishing compound but, unsure what type of rod to used. Will be interesting to see changes after you polish. I wonder if the head size on the pellets is to small to stabilize the pellet for longer range. In Steven's ytub where he is testing the avenger 25 with his avs slugs, he found that .254 worked better. I have tried to measure jsb 25.39 pellets and was getting .2495 - .250. Any thoughts.
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Do yourself a favor and buy a compressor, hand pumping takes all the fun out of it. For about $360 on Amazon I think you can still buy a fully self contained ac/dc model that can also work from your truck battery in the field. I love mine. Also for lapping the bore Amazon sells 3M polishing paper and one pack comes with 6 different grits. Cut appropriate size strips to glue to a dowel or cleaning rod with rubber cement. They are color coded by grit and I would be cautious about using the coarser grits. The JB by itself is not up to the job.
Many others seem to prefer their regulator backed off but my goal is accuracy at longer ranges so Im not willing to give up the velocity and will keep it set high.
It takes about 3 or 4 minutes to charge from 3000psi to 4000psi that I fill to and at full power I get more than 4 mags from a fill.
Im still taking advice on slug diameter and YouTube videos recommend the smaller diameter but testing will tell, I ordered .249 I think.
Tom
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Following
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Tom, I did a test on pellet head size. I measured the remaining pellets in the tin. The majority were .2470 - .2475 and .2480 - .2485, also had 7 that were. 2445 - .2465 and a group of 16 that was .2490 - .2495. I first shot a 3 shot group with each heads size.
.2490 - .2465 had a flyer shot the remaining
4 shots. Had 2 groups about a 1/2
apart.
.2470 - .2475 had a flyer as well out of it's 3 shot
group.
.2480 - .2485 grouped well so I shot 2 more for a
5 shot group that measured
Tried to post a pic of the target but, couldn't get it to attach.
1/4" CC.
.2490 - .2495 grouped well also, did a 5 shot
group of 5/16" CC.
Could be an indicator I am seeing flyers at 100 yards. Will try a test at 100 yards with the better groups when I can.
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Tim,
Like you I am unable to ad a simple picture attachment to a post and have mentioned to the GTA staff that the forum is due for some modernization. They seem content with what they have so I guess there will be no pics.
Good work with the pellet diameter sizing for your testing, I have yet to do that. I shot some more this evening and my results just keep getting worse but at 75yds moa accuracy shouldn’t be asking too much. But flyers and just plain wandering of groups continue with the same H&N 27gr hollow points that last year would shoot 1/2” groups at 50 yds. My range is great for watching the projectile fly as the sunlight illuminates it well and from the bench with my 6X32X44mm Meuler target scope I can see it’s entire flight and it’s pretty ugly. Skirt wobble and yaw in the air predicts that it will go off point of aim, but about every other shot flies true and hits where I aimed.
I received my order of slugs from Nielson Specialty Ammo today and only shot two clips of the 33grs and while wobble and yaw didn’t happen the group wasn’t that great either so I put it away for today. Great quality product and I bought some for three different calibers. My next focus will be the bore lapping I had mentioned but first I think I will try backing the reg off to 23 or 24000psi as others have reported success by doing this. Not loosing velocity is important and I will monitor what changes with a chronograph.
Tom
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Tom, thanks for the update. I will try the .2480 - .2485 and .2490 - .2495 at 50 and 75 yards the next chance I get when this wind lays again. I did order NSA slugs in .249 and .250. Currently the tune is set at 1700 reg and hs in 7/8 turn, close range pest control. JimD has his set to 2100 psi, i think. I will up mine to 21-2200 psi and reset the hs. Ordering one of the cheap China chronographs to have a base line. Will order one of the air compressors you were talking about. I hate to dump the air as it takes about 250 hand pumps to bring it back up. Will keep you posted.
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Tim,
Here is a link to a YouTube video about different Avenger 25cal tunes for different purposes. Very informative and I plan to use them as a base line. The Chinese chrony works and is good to have. I have several but this one is so quick and easy to use that I use it often. The compressor is a ‘must have’, you’ll wonder how you ever put up with hand pumping and will shoot much more now.
Tom
youtube.com/watch?v=Y50QJzAUqm4&feature=share
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Tom, viewed the ytube link, most interesting. I moved the reg to 2300 psi. I received my NAS slugs and did some testing. At low velocity under 800 fps . NAS 26.8 .249 @ 786 fps and NAS 34.9 .250 @ 686 fps. 3 shots of each slug.
5 of the six made a group of 5/16 x 1/4, as I increase the HS the groups increased to 1-1/2 to 2". The closer to 900 fps I got the larger the group. Turned the HS down to 2 in and shot a 5 shot group. 4 of the 5 made a hole a little larger than the slug. Decided to sort the slugs by size.
NSA 34.9 .250 45.45%
.2495 31.81 %
.2485 22.72%
This was a sample of 44 slugs. Plan on going to the range tomorrow and test these out by size @ 50 yards, if that goes well, will try 100 yards.
I am confused at this point as I thought the sweet spot would be 850 to 900+ fps. So far it seems to be under 800. Any insight would be appreciated, will post tomorrow's results.
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Whoever had the reg set at 1500……yes that is much too low on a 25 cal. Mine is 2100-2200 and I think on the absolute lower end of the useable range. Mine is super accurate out to 50 and I know they are capable but I think 75 and 100 consistently is much to expect from it.
It was me and I stated at the outset that that was on my .22 cal. I do however have a .25 Avenger rifle as well.
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Spin, I agree with you that 1500 is to low for 75 to 100 yards and am becoming of the same opinion, that it may be to much to consistently expect. I do tune down to 1700 for short range pesting out to 35 yards. It is fun to keep trying though.
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Tim,
I did some slug testing in my 25cal Avenger this evening and here are the results at 50yds; H&N 34gr slugs @762fps shot a 5shot .995”group. NSA 38.5gr. Slugs @667fps shot a 5shot .859”group. Of note was that the H&N group was 2 1/2” left of my point of aim while the heavier NSA slugs were a little lower but remained vertically correct to my previous scope setting for 28gr pellets. Good to know for field use.
My hammer spring was turned out 1 1/4” for these tests. While I plan to do most future slug testing at nearly full factory power with the hammer spring in nearly all the way we will see what happens. While testing the muzzle velocity I mentioned above both slugs fully penetrated a 2X6 fir wood block at close range. I suspect the hammer spring adjustment on my Avenger may have a problem noted by others with a restricted travel of only 3 1/2 turns out but I will fool with that in the future as the goal here is power and long range with accuracy, and I don’t much care about the lower end for now.
Your mic specs of pellet sizes is interesting and I have done some of my own.[size=78%] [/size]
[/size]
[/size][size=78%]Contrary to posts by others commercial pellets seem to have larger diameter skirts than heads, and while there may be reasons for this it cant be conducive to accuracy in a non choked fine rifled bore. Like you I also have 22cal rifles and tonight measuring the waist against the head diameter in 22 cal I find the waists measure on average about .010 larger. The greatest example being in the Sig 16.6gr @ .016 oversize. This testing was done in my Cayden .22 rifle and the results were that the nearly pure soft lead Sig Dagger pellets at 50yds outshot both H&N and JSB”s of harder alloys. I blame it on the extreme choke in the Cayden rifle bbl., Go figure?[/size]
Tom
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Tom,
Thanks for the update. I am still trying to get a consistent group at a 100 yards. I am not sure this is feasible. My avenger has 6 full turns on the hammer spring. I have tested up to 3-1/4 turns with NSA 34.9 slugs at 797 fps. Currently the regulator is set @ 2300 psi, but it also has 400 psi creep, so I am reluctant to raise the reg higher than 2500. I plan to continue increasing the hammer spring in increment up to six full turns and see what I get with NSA slugs. Will try to test at 50 yards later this week and post a update.
At 3-1/4 hammer spring turns in the 25.4 pellets are at 930 fps.
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Tim,
The 400psi creep you mention seems excessive, so I would suggest that for testing purposes for now that you delay your shot between shot time to overcome that being a factor for bench target spread. I still believe that a consistent 100yd moa is achievable with the 25cal Avenger but I’m not close to that yet and I’m stuck at 75yd testing so far.
A lifetime of shooting powder burners has taught me that high pressure is not necessarily the enemy of accuracy when combined with the correct bbl. and projectile, so I will continue testing from the top down, 3000lbs psi is nothing that should interfere with maximum accuracy. But peak pressure timing and continued pressure and drop off until exit does make a difference.
I have worse accuracy problems with more expensive pcp rifles and I am getting better results with the 25cal Avenger at 75yds. than with the others. Much testing and mods has convinced me that the issue is with the less than perfect bores and projectiles of all these pcp rifles, especially with the choked ones. I have removed the bbls of others and lapped and polished them with a great improvement (but they still foul quickly) but not yet on the Avenger. Next week the bbl comes off to see if I can first chemically remove the lead fouling before lapping off all the high spots. Then polish whats left to the best it can be and we will see what the Avenger bbl is capable of. The bottom line will always be that there is no substitute for a perfect bore. I believe this rifle will shoot moa at 100yds but I'm just not there yet.
Tom
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Tom,
Thanks for the update. I am going to test to see how long it takes for the 400 psi creep to occur, up to 2000 psi reg setting it has 200 psi creep. I am going to test groups at 35 yards with different hammer spring settings, up to 6 full turns in. Will see what group sizes I get with pellets and slugs.
I did order some of the polishing paper you suggested. What are you using to lap the barrel before polishing.
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Tom,
Thanks for the update. I am still trying to get a consistent group at a 100 yards. I am not sure this is feasible. My avenger has 6 full turns on the hammer spring. I have tested up to 3-1/4 turns with NSA 34.9 slugs at 797 fps. Currently the regulator is set @ 2300 psi, but it also has 400 psi creep, so I am reluctant to raise the reg higher than 2500. I plan to continue increasing the hammer spring in increment up to six full turns and see what I get with NSA slugs. Will try to test at 50 yards later this week and post a update.
At 3-1/4 hammer spring turns in the 25.4 pellets are at 930 fps.
OK Bucko's Remember when we discussed possible methods to dampen out harmonics out? Remember when I brought out making cylindrical plastic or rubber bushings using o-rings on the O.D.'s spaced out on the barrel length so as to aid in holding the barrel centered in the shroud and dampening (or eliminating it) Well I guess somebody was either of like mind or was listening to the discussion because it's out on the market and even has the holes drilled through the width of the bushing/spacers to allow movement of air within the shroud. I also mentioned that.
Apparently it gets the job done and it does it well. Cost's $28.00 with free delivery. I am going to put an order in tonight. Here's info and a video. ( I'd put a hold on other aspects of setting up for long range shooting till wee determine how these Bad Dogs work. I have a very good feeling about this. link; https://www.youtube.com/watch?v=q_aNCJEx510 (https://www.youtube.com/watch?v=q_aNCJEx510)
and link; https://www.ebay.com/itm/175292578021?ViewItem=&item=175292578021 (https://www.ebay.com/itm/175292578021?ViewItem=&item=175292578021)
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I agree, the principle is sound. As evidence two aftermarket bbl bands (3D printed) on other rifles I have broke during use showing me that force is being retained at the bbl contact point. I also had ordered the shroud/bbl centering rings offered for the Avenger from eBay but have yet to receive them.
Casual shooting of the 25cal Avenger this evening at 75yds with JSB Diablo 25.39gr pellets was decent however with a 5shot group into 1.09” but 3shots in one raged hole reminds me that this gun has potential.
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Tom and Jerry,
This sounds like a good solution to Jerry's earlier discussion. I like the idea of these bands being spread across the barrel instead of one point. I also ordered a set, it said the last one. Hopefully will be here in a few days. I continue to look for a way out of this rabbit hole, not sure there is a way out. I feel the rifle has the potential as I have shot 5 shot groups with 3 of the shots making a 3/4" group with 2 flies making a 2" group. I appreciate the input and insight from both of you. Will post an update when I am able to test again, maybe tomorrow.
Thanks again Tim
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Tim,
You mentioned that you have ordered polishing paper to smooth your bore and have some questions. Using these papers with oil is a very good way to remove high spots and does help noticeably. Reason being is that commercial factory bores are very flawed and at least this process will remove some of the high spots, and while improving accuracy will also prolong lead fouling. Any dowel or cleaning rod you can attach these papers to will do the job. When you are satisfied that you have removed the high spots with the coarser paper you can go to the finer papers to smooth it finer, then finish with metal polish. This helps greatly but has no affect whatsoever on the oversize groove diameter flaws in the bore.
True lapping of a bore is very different from what you hear discussed in these forums and is usually reserved for fine target bbls, and that process includes the grooves as well as the lands. It is a very laborious process that usually requires a fine target bore to be successful with very little bore run out to start with. Keeping it simple the process requires molten lead alloy to be poured into the bore and after hardening removed. From that casting a lapping slug can be made that will fit both the lands and the grooves, and when passed back and forth with various compounds will truly polish both the lands and grooves of a target or damaged bore to near perfection. I don’t think Avenger bbls are ready for this. FYI.
Tom
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Tom,
Thanks for the update. I am still trying to get a consistent group at a 100 yards. I am not sure this is feasible. My avenger has 6 full turns on the hammer spring. I have tested up to 3-1/4 turns with NSA 34.9 slugs at 797 fps. Currently the regulator is set @ 2300 psi, but it also has 400 psi creep, so I am reluctant to raise the reg higher than 2500. I plan to continue increasing the hammer spring in increment up to six full turns and see what I get with NSA slugs. Will try to test at 50 yards later this week and post a update.
At 3-1/4 hammer spring turns in the 25.4 pellets are at 930 fps.
OK Bucko's Remember when we discussed possible methods to dampen out harmonics out? Remember when I brought out making cylindrical plastic or rubber bushings using o-rings on the O.D.'s spaced out on the barrel length so as to aid in holding the barrel centered in the shroud and dampening (or eliminating it) Well I guess somebody was either of like mind or was listening to the discussion because it's out on the market and even has the holes drilled through the width of the bushing/spacers to allow movement of air within the shroud. I also mentioned that.
Apparently it gets the job done and it does it well. Cost's $28.00 with free delivery. I am going to put an order in tonight. Here's info and a video. ( I'd put a hold on other aspects of setting up for long range shooting till wee determine how these Bad Dogs work. I have a very good feeling about this. link; https://www.youtube.com/watch?v=q_aNCJEx510 (https://www.youtube.com/watch?v=q_aNCJEx510)
and link; https://www.ebay.com/itm/175292578021?ViewItem=&item=175292578021 (https://www.ebay.com/itm/175292578021?ViewItem=&item=175292578021)
i thought about this too the avenger barrel is 11mm OD very thin, you could fit a 12x14mm cf tube and .5mm orings would do more for rigidity probably
for $28 you could even get 2 cf tubes, one 12*14 and one 14*20 making it HELLA stiff
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Tom,
Thanks for the explanation on the polishing. Will give it a try when I get a break in pest control. Did some test across the chronograph today at 5-3/4 turns in on the hammer spring running 970 fps with jsb 25.39. Tried nsa slugs with this hs setting, 3 inch group. Will have have turn hs back down. Will keep you posted.
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I received the barrel dampening/barrel, shroud centering kit. Wow! That was fast. I'd install them but I'm waiting on a pellet bumper
and play a bit with heat shrink tubing. It's likely that my .22 Avenger is due for a shroud/barrel and internal moderator cleaning. I think I'm going to try using denture cleaning tablets & water on the moderator. Might as well get it all done at the same time.
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Jerry, please keep us updated on how the barrel dampening goes. I have ordered mine and should be here next week. It will be a couple of weeks before I will able to install mine. Have you polished your barrel bore.
Thanks Tim
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I’m looking forward to receiving the internal bbl/shroud centering rings, and I also think that with the holes drilled in them they should help in sound reduction. For baffle cleaning If you have a vibrating cartridge case cleaner then just ad a capful of paint thinner to the media for cleaning your moderator baffles. I presently use aftermarket internal shroud baffles with an external moderator, as well as a hole drilled in the shroud at the muzzle end that I have covered with several layers of dense foam. My 25cal Avenger is my quietest pcp.
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Jerry, please keep us updated on how the barrel dampening goes. I have ordered mine and should be here next week. It will be a couple of weeks before I will able to install mine. Have you polished your barrel bore.
Thanks Tim
I gave it a light polishing using only a brass cleaning rod, brass cleaning tip, and cleaning patch material dressed with a red jeweler's rouge. Straight push, pull in and out of the barrel and rotating the position clockwise 45 degree's then advancing it 22 1/2 more and again going through the same process. I repeated this a half a dozen times. Also polished on a small radial chamfer although it's really too small
to protect the edge of the bore from getting dinged inward and swaging metal outward deforming the bores edge so I going to revisit that little upgrade.
One thing I am concerned with is the idea of using tape around the barrel to keep the dampening discs in position. Oil! the use of it for lubing the barrel to assist in positioning and keeping them in position on the barrel. Oil is going to degrade the adhesive on the tape likely
softening and turning it into ineffectual slime. I'm still muddling alternatives or an easy fix to that. A wire wound say 3 timed around the barrel and a tight double twist around each other tightly. That may do the trick and oil would not be a concern. Oil Should Be Silicone Based!
if you lube the shroud's bore. Lastly the instructions tell you should the deadening baffles bores are too tight to use a fine rasp to enlarge them for a snug , sliding fit. I'd say buy a hardwood dowel around the size of a pencil and cut off a 4 in. piece. Use a fine bladed coping saw oe fine hacksaw and slot one end to allow you to slide in a doubled over a strip of say 120 grit emery paper. Stick it through, wind it around your wooden arbor, grit side out and chuck it up in a variable speed hand drill. You DO NOT want to use an air grinder or moto tool as they have too high an rpm. You want to go pretty slow, checking your fit often and doing your best to keep things straight and squared. Myself
I have a small bench top drill press and V blocks, grinding vices, but in the end I will likely end up holding the baffle and working it in and out and around in a circular motion. as long as the emery paper isn't too tight in the bore and you keep the rpm's reasonably slow it should be OK. Take your time! Anyway That's my plan.
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Jerry,
Thanks for the update, I wonder if plastic ties on each side of the baffel would hold it in place or would it create a vibration issue.
Thanks again.
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I don't think so. Cut then to the same length so mass and weight are the same. If anything I think they would reduce vibrations along the lines of the silencers on a bowstring. As long as they stay in place (and several wraps and the end twist all compact and tight) they should do the trick. Let me tell you, you want to pull that shroud off and clean both it's interior and the barrel and the discs lets say every 6 mo.s or so if you do a lot of shooting. Oil, dirt and particularly lead dust can create a gummy adhesive coating on everything inside that shroud. Getting my internal
moderator OUT of the tube was a major league PIA. My internal moderator fit's tightly in the bore of the shroud using 2 just about perfectly fitting o-rings just like these anti-vibration baffles. I very highly recommend using Ballistol for cleaning before tearing down the setup on the barrels. As long as the discs stay in position I'd just , spray, brush and wipe off. Lightly oil the cleaned bore of the shroud and slide it back into position then screw it back securely.
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While I'm intrigued by the use of kinetic sand as a acoustic deadening medium I have some pertinent (at least I think so) questions on
the practicality of it's use. Kinetic Sand is in basic terms, sand mixed with silicone oil. They packed the hollow butt stock with it and packed the
void area inside the barrel shroud. Alright so would that not make air stripping much more important? Will flipping be more of a problem?
Watching the reaction of the encapsulated kinetic sand sample to repeated impact really threw me and seemed opposite to what I was told while researching it. Compaction? and in the extreme no less. The video I watched narrator claimed the side of the encapsulated sample
with repeated impacts became rock hard? Would have to be removed with a grinder? I'm a bit put off by such a prospect and how much energy
would it take to make a significant difference in the sand surrounding the barrel? If the silicone oil gets displaced by hard or thickening sand
how would the remaining liquid affect performance? How even would the distribution of the hard solids sand and the now extra oil/sand mixture be? Questions, questions! I hope we get to see how things go with this setup as time and steady use continue. A gun prepared with sand packed in the forearm stock, butt and shroud is likely to be religated to bench shooting. But there a gun is likely to see a great deal of shooting. I look forward to seeing it
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Jerry,
Thanks for the insight of cleaning of the shroud. I think the rabbit hole is getting deeper. These are very interesting concepts. A little more understanding as we move along. I appreciate your perspective as some of these things I haven't thought of.
Thanks again.
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I received my order for the bbl shroud inserts for my 25cal Avenger today and they are just what I wanted and look good. First let me recommend that you don’t over think this process! Any solid materials like a sand pack will defeat the reason for having a shroud, and unlike with firearms we are only dealing with 3000psi. I often use electrical tape around the bbl exterior for reasons other than anchoring these shroud rings and so long as there is no oil residue on the surface it stays put.
It will be at least a week before I get time to install these and at that time I will also remove the bbl for a proper polishing. I will post the results.
Tonight I tested the Cayden 22 pcp I have been working on that really needed help, and at 75yds it finally put 5 shots into one ragged hole. Success feels great and I expect the same from the Avenger at longer ranges in the future.
Tom
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Tom, thanks for the update, I also received my bbl/shroud inserts. It will be a week or so before I will be able to install them, can't break my avenger down at this time as I have had a increase in a pesting issue, once resolved I will work on it. Will be interested in any results from you efforts.
Thanks again.
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Tim,
I used 5 different grits of polishing paper hoping to take off the high spots in the bore and spent hours on it, then thoroughly cleaned and then polished with Semi-Chrome metal polish for a final bright finish. Inside my shroud is now a very unusual array of aftermarket parts. Starting with a 1/8” hole drilled in the shroud at the breach end it’s followed with four wads cut from a ‘Mr Clean’ pad to buffer escaping sound under pressure, then three of the aftermarket shroud harmonic centering discs, then the factory dual O ring shroud centering piece, followed by the last aftermarket centering ring. The muzzle tip has an aftermarket air striper with an O ring to anchor the muzzle to the shroud. It’s all held in place with black electrical tape to anchor it. Then mine is followed with interior baffles and an exterior suppressor. After all of these attempts to reduce harmonics and tensioning the bbl in place with the shroud it’s clear that the only remaining slop now comes from the contact point between the exterior bbl shroud retainer and the shroud itself. So While a copper shim would be preferable I made shims from paper to center the shroud/shroud retainer in a solid place. Couldn’t be better.
I ran out of daylight and the scope required huge adjustments and I wasn’t able to properly test my results on paper, but first impressions were good and I was able to hit pistol cartridge cases at 75yds. 1 1/2 turns ‘out’ on the hammer spring at 2900psi reg setting with JSB 15.89gr.
We will see,
Tom
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Tom, Thanks for the update. It sounds like you are making progress. I am looking forward to installing the shroud rings and polishing the bbl. Will be interested in your testing and if the flyer issue has improved. I have a pesting issue to deal with before mine can worked on. What did you use to ream the inside of the bbl shroud rings. I am thinking a wooden dowel and sand paper. I received 5 shroud rings, and I think you only mentioned that you install 4. Wondering if you only received 4 or left 1 out for some reason.
Thanks Tim
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Tom, Thanks for the update. It sounds like you are making progress. I am looking forward to installing the shroud rings and polishing the bbl. Will be interested in your testing and if the flyer issue has improved. I have a pesting issue to deal with before mine can worked on. What did you use to ream the inside of the bbl shroud rings. I am thinking a wooden dowel and sand paper. I received 5 shroud rings, and I think you only mentioned that you install 4. Wondering if you only received 4 or left 1 out for some reason.
Thanks Tim
I only received 4 rings with my order. I believe that was the specified number. Tom how did the gun sound? Was there a noticeable difference?
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My gun is already very quiet and I was afraid adding those centering rings might interfere with that but they didn’t change anything. Best I remember I received 4 rings and I placed 3 before the factory centering piece, then one more after that ending with my air stripper. That followed with baffles and then the moderator like it was before. So far I find no change in accuracy and Im hard pressed to blame inaccuracies on the shroud. I will say that my non shrouded Cayden 22 is now producing consistent moa at 75yds.
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Thanks for the update. I received 5, 4 tan and 1 gray. Will install all 5 when I get the chance. Those alone with the factory original, should change something,I hope. Will post results when installed.
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nuts!
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Tom and Jerry
Installed all 5 bbl bushings and only had time for a quick test at 23 yards. Had 2 5 shot groups that were 1/4" ctc. Will go to the range at first chance and see how it performs at longer ranges.
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When you guys are making these modifications how and what are you using for a shooting rest? How are you dialing in the crosshairs? Lead Sled or equivalent, Tripod, Sand Bags, Gun Vice? Are you zeroing the gun on target manually, mechanically?
If you have the "Biting Money" or access to high end gear it would be great. If not I'd sand bag the ever lov'in snot out of the gun on a dead solid bench. The more you remove the human element in extreme benchrest and have comparative ( before and after performance) the better. Same methods, same day, weather, ammo, the whole megillah. Them play with laying a few sandbags against and across the shroud when shooting.
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Jerry at home I can shoot up to 35 yards. I shoot off of my router table with locking wheels, bipod on rifle and sand bag under rear of stock. I lightly rest check on stock and light finger on trigger. At the range shoot off of a steel bench concrete in the ground, rifle same as at home. I have tried lead slead with pb with poor results.
I was able to test some more this morning at home at 35 yards. Continue to have the same results, issue 3 shots in nearly same hole then next open up to 3/8 to 1/2. If weather holds will try for the range and see what I get at 50 and 75 yards. If I don't see any improvement there then polish the bbl. Will keep you posted.
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Another thing to look into if using the mag. is it damaging some of the pellets when cycling.
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Another thing to look into if using the mag. is it damaging some of the pellets when cycling.
I was just about to type the same thing.
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Thanks for the insight. I have only used the single shot tray as it is one less variable.
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Sorry if I missed something but I think the first thing to do on the barrel is to polish the crown using a brass screw and prefereably some JB paste. You could also use Flitz or another metal polish but it will take longer. Should be simple 5-10 minute job and may solve issue with very little downside risk.
I polished the bore on my P35 in 25 caliber but I did not see any significant effect. Doesn't mean you won't. I'd push a pellet first to see if it has tight and loose spots or another reason it might need polished. If it feels smooth I probably would not polish it. But if you go slow and use nothing more agressive than JBs it should not hurt.
The lead, there the pellet transitions to the rifling also needs to be smooth enough it does not damage the pellets. Sandpaper on a dowel can smooth it. I did this too on my P35 but again, it did not seem to change anything.
To be confident it is the gun and not the shooter, it is a good idea to have a gun that doesn't have these fliers. I know a lot of my larger groups are just me. But a nice light crisp trigger really helps. I had to do a lot of adjusting on my Avenger trigger before I was happy with it. It's better than my bullpup triggers now, however. To give an example, I shot a couple groups with my P35-22 today. I was checking to see if I messed up when I bought 5.51 instead of 5.52 pellets. I shot at 25 yards. My first group was about 3/8 but the first shot was to the left a little, the direction of my trigger pull (I shoot from the left shoulder). I think I pulled it a little. Next two were touching. Second group was about 3/16. I've shot better with the 5.52s but I've also shot worse. The P35 does not have as crisp a trigger as my Avenger. It's under 1 lb but has some creep. Not sure if the 5.52s shoot better or not but my conclusion is the 5.51s will be OK.
I did a thread on this but if you haven't adjusted your eyepiece so that your head movement doesn't shift your point of aim, you need to do that. It can easily cost your the amount of your fliers.
My Avenger 25 has only the stock spacer in the shroud, holes at the back of the shroud, and an aftermarket "moderator" in the shroud. I get 1/4 or smaller groups out of it at 25 yards regularly. When I do not, I am pretty sure it is me. I modified the shroud to make it quieter. It is about 85 db now 1 ft ahead of the muzzle and 1 yard to the side. I'm not saying other things may not help your rifle, only that mine has not needed these things.
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Jim thanks for the post. I am going to test at 50 to 100 yards. If still having flyer issues will have to pull the bbl, crown as you suggested, clean bbl and run a pellet through it to see if there are any tight spots, if so polish. I have worked on the trigger as you described in one of your previous post, still to heavy, will have to revisit it.
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One streak of lead in your rifling can cause a flier. If the flier removes it then the next shot is on but could possibly leave a new lead streak and cause another flier. So, even though I only brushed over all the chatter in this topic, you need to see just how rough your barrel is. I think someone mentioned that the bores on these guns are rough. You can spend every dime you have on trinkets that claim to make the gun a Daystate beater, but if your bore likes to collect lead, you’re chasing your tail.
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One streak of lead in your rifling can cause a flier. If the flier removes it then the next shot is on but could possibly leave a new lead streak and cause another flier. So, even though I only brushed over all the chatter in this topic, you need to see just how rough your barrel is. I think someone mentioned that the bores on these guns are rough. You can spend every dime you have on trinkets that claim to make the gun a Daystate beater, but if your bore likes to collect lead, you’re chasing your tail.
It would appear so yet decades of shooting by myriad serious experienced shooters shared anecdotal results seem to contradict it. At least to a certain extent. That side of the fence says a somewhat dirty barrel edges out the freshly scrubbed, antiseptically clean bore. I'm still sitting on the fence myself. I find the clean, smooth bore to be the intuitive top performer but even setting years of tried and true results aside
there are flaws in the "Grab the polishing rod and abrasive and start grinding away. For example you can scratch, abrade, and polish some of the dips and high spots in the minor bore dia. you aren't doing much about the bottom of the grooves.
Next, Is it a good idea to grind and polish out a choked muzzle? Generally they are there purposely as they tend to improve performance with pellets.
And the results of extensive sanding with a long flexible shaft and a flapper type of arrangement will Not Give You a truly round inner bore. Gun drills and boring bars and I'D' grinders cut their own path and polishing sticks? - Not so much, not at all. You Can do it with specially made brass expanding laps but to do that all alone manually? That would get old fast and take a lot of man hours. Truth be told and
shiny, reflective surfaces both withstanding, if really subjected to truly precise measurement you see that there is still tight areas, low spots, over polished areas. In the machine trades making a part acceptable with file and emery was often called tongue in cheek as "bull$hitting it in."
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If you push 2 or 3 pellets through from breech to muzzle and can feel obvious tight and loose regions, a poured lap (and a lot of effort) is the right prescription.
However for most modern barrels, the bore will be sufficiently uniform but with a rough surface...in which case a compressible implement (jag+patch or mop or felt pellets) loaded with a light abrasive will go a long way to mitigate rapid lead accumulation.
As I mentioned earlier in the thread, the bore of my .22 Avenger was one of the roughest I’ve ever seen. I can shoot it now much longer before needing to clean it.
Meanwhile, any regimen that might be described as “grinding” is almost surely a bad idea.
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. In the machine trades making a part acceptable with file and emery was often called tongue in cheek as "bull$hitting it in."
We used to call those guys “Dotco Machinists”, and yes, there are still a lot of them out there.
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The term “grind” should never be used about anything barrel related. All barrels collect lead. A barrel that has fliers should be inspected for a spot that is grabbing a lot of lead. You can try to fix a questionable barrel or just replace it. My P15 had the dreaded flier syndrome. Take away the fliers and it was very accurate. It was the leade. It was cut just a little too deep. When I seated each pellet a little deeper with a L hex wrench, the fliers went away. So did the barrel. Had to build a new one. I know that the current hype surrounding airguns is brainwashing guys into believing 100 yards is a walk in the park and everyone’s gun is a MOA 100yrd powder burner equal. The reality is 100 yards is no joke with an airgun. With the slow lock time, giant hammer sliding down a tube to strike a valve pin, so many things start to rear their ugly head at 100. Personally I would shoot the gun at 50,60,70,80,90 and 100. See at what range the fliers put you outside of what you consider acceptable accuracy for a $300 gun. Flier diagnostics can be very frustrating. Especially when they are at normal realistic pellet ranges. You are operating at the extreme edge of pellet range with any hope of consistency at 100. So if you want to be a 100 yard guy maybe give the 33gr pellets a try or commit to going broke and possibly breaking a cheap gun by chasing the slug dragon.
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"I know that the current hype surrounding airguns is brainwashing guys into believing 100 yards is a walk in the park and everyone’s gun is a MOA 100yrd powder burner equal. The reality is 100 yards is no joke with an airgun. With the slow lock time, giant hammer sliding down a tube to strike a valve pin, so many things start to rear their ugly head at 100. Personally I would shoot the gun at 50,60,70,80,90 and 100. See at what range the fliers put you outside of what you consider acceptable accuracy for a $300 gun. Flier diagnostics can be very frustrating. Especially when they are at normal realistic pellet ranges. You are operating at the extreme edge of pellet range with any hope of consistency at 100. So if you want to be a 100 yard guy maybe give the 33gr pellets a try or commit to going broke and possibly breaking a cheap gun by chasing the slug dragon. "
Yep! I agree though it can be fun and a real learning experience. 100 yard MOA is no easy win for gun or shooter let alone consistent repetitive sub MOA.
Now as to slamming the Avenger! "Fi on Thee foul Varlet" Curb your tongue Knave! ;D
Really the Avenger is fast becoming if not already there, as an iconic gun and has and continues to, boost air arms and their popularity.
Despite hitting the market with a price tag just under $300.00 it was eye opening accurate and had features not seen in air rifles until you dropped well upwards of a Grand. And that's no small deal.
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Oh I’m not slamming an Avenger. They are what they are. Probably a good gun with a decent lifespan if you keep the tunes conservative. When you want to push heavy stuff or stuff with a lot of drag fast, it requires higher pressures. Higher pressures require heavier spring tensions that work on sears and linkage. The whole gun can become harmonically angry. Some guns are built to take it. Some regs are designed to handle you constantly fiddling with them. I don’t own one but just from a price point and country of origin standpoint, I would keep things conservative. Then focus on refinements.
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My Avenger needed a longer sear adjustment screw before I could get the pull weight down. I don't remember the size right now but I'm sure I have posted it here before. I got what I needed at the local Home Depot. That was the big change. I then messed with the other screws and eliminated the first stage. So now I have a nice crisp under 1 lb single stage trigger pull.
My bullpups have to have a first stage but I lightened it a lot. It doesn't really bother me now. I can only eliminate it by eliminating the ability for the safety to work. I also got the pull under 1 lb, usually. There is a fair bit of variability and a little creep sometimes. They are OK but they are not as good as my Avenger or Prod. Even though the trigger pull is a bit worse, I like my bullpups more than my Avenger due to their more compact size.
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Hi Guys, I took a slug .2520 marked with shapie, loaded into breach, locked up, pushed back out with wooden dowel. Looked at the land groves with close up photo. Multiple striation running the length of the lands. Took another slug and flattered out a little to .2540. Repeated the same procedure, thinking it might see the grove marks. Concerned that no grove marks appear and pellets and slugs aren't sealing off. Will try to repeat with larger dia and see I can hit the groves. From the looks of the lands, polishing is going to be required.
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Hi Guys, I took a slug .2520 marked with shapie, loaded into breach, locked up, pushed back out with wooden dowel. Looked at the land groves with close up photo. Multiple striation running the length of the lands. Took another slug and flattered out a little to .2540. Repeated the same procedure, thinking it might see the grove marks. Concerned that no grove marks appear and pellets and slugs aren't sealing off. Will try to repeat with larger dia and see I can hit the groves. From the looks of the lands, polishing is going to be required.
Tim the slugs might be an entirely different matter but, I don't think pushing a pellet through the bore by hand using a rod. Water tank recover is likely the best method of recovery without distortion of the projectile. Pellet skirts will seal quite well when they get what your rod isn't giving them. One wicked powerful blast of H.P. air up the rear which does a pretty good job of flaring out the skirt and keeping a modicum of air pressure working forward and outward against the I.D's walls.
Slugs may be another kettle of fish but some rifles deliver power and outstanding accuracy with pretty minimal engagement with the lands. The original FX Smooth Twist for example that made ideally pretty light contact with those barrel's radial shaped lands.
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Meanwhile, any regimen that might be described as “grinding” is almost surely a bad idea.
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Not really - https://www.merriam-webster.com/dictionary/grind. (https://www.merriam-webster.com/dictionary/grind.)
Way back in prehistoric times when I was an apprentice we had a discussion about what actual class of machining operation "Grinding"
really is. The answer, the overwhelming time, is "Cutting" The abrasive grit in carbide silicate and aluminum oxide, diamond, borazon, zirconia
etc are in fact very hard, sharp edged grains held in a bonding material. Like a bit in a lathe or mill cutter the remove material in very small "chips". They eventually dull and the wheel's grit is sharpened by dressing the wheel. This is the act of exposing new sharp underlying grains
or removing workpiece material from building up around the porous area around the impacted grit. This is called pinning. Working with a sharp wheel is necessary. There are times when a broken in abrasive is used but this is only for a very fine final polish. You may only be removing a few Millionths of an inch. For what we are doing when you are ready for that last polishing fold that very fine emery with grit sides facing each other and rub the two sides against each other making sure you get the entire abrasive surfaces so as not to leave large sharp grains intact that will scratch and scar the work surface. Blow and wipe the Emery grit off before you use it.
As for polishing the bore with soft givable material like a bore mop try doing it with diamond lapping paste. It is very fast cutting ad delivers a really great surface finish. You usually buy it in a syringe as it is a paste. It goes a longggg wayyy. You can buy it from "Grainger's"
P.S. if you want to put a true Surgical edge on a blade dress a strop with this stuff.
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Air venturia avenger 25 JSB 25.39, will group 3 shots in 1" or less at a 100 yards, but consistently has 2 flyers out of 5 shots. I am trying to figure out what is causing the flyers. I have tried 2 different scopes, 3 different pellets, the same results. Wondering if the regulator could be the issue. Regulator is set at 2100 psi, fill to 3300 psi. All pellets out of the same tin. Any insight would be appreciated.
Are the fliers all ending up in the same area, like they are grouping together? Or are they random?
100 yards gives alot of time in flight to be affected by wind and even pellet deformation. Most guys shoot slugs that distance to counter those issues. Have you tried shooting closer to see how it groups. I would try 30 yards, then 50, to see if it repeats itself.
This is one of the best discussions on accuracy and tuning I've found so far. Well worth the time and effort to watch and listen to IMO. link; https://www.youtube.com/watch?v=xzDjjfYvYXc (https://www.youtube.com/watch?v=xzDjjfYvYXc)
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In the common parlance of gunsmithing and among machinists I know, the term grinding represents the rapid removal of material with a coarse abrasive. At the very least, something distinguishable from typical bore treatments or repairs, and most definitely outside the realm of what Pelletjunkie and I have been describing.
So while the textbook definition may cover a sufficiently broad range from lava rocks down to 0.1 micron polishing compound, speaking on the forums of grinding a bore will elicit a pucker response from most of the readership so I will refrain from referring to it that way.
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Thanks for the replies. Will look at pellet water catch of the pellet. Will watch video on accuracy when I can get 2-1/2 hour block of time , sounds very interesting.
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Thanks for the replies. Will look at pellet water catch of the pellet. Will watch video on accuracy when I can get 2-1/2 hour block of time , sounds very interesting.
I watch a lot of YT videos. Normally at 1.5 or 2X speed, just click on the setting button for playback speed.
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Thanks, I'll look at the play back speed.
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Tim & Jerry,
I devoted today to testing the Avenger 25cal for accuracy and flyers at 75yds, both slugs and pellets. While the goal is 100yds I’m still stuck at 75 as even after my mods it’s not improving. Slugs tested were H&N 30gr and 34gr, and Neilson Specialty 36gr and all miked between .250/.251. It hated the 34grs and the other two were similar holding to about 1 1/2” at best but with flyers. Same setting shot JSB 15.89gr pellets better, about an inch but still with a flyer.
So I changed the reg setting and hammer spring to the ‘Pro Setting’ at 2400psi and hammer spring in only one turn. Everything got worse and the poi changed by 3”in all directions. I tried many hammer spring settings at this pressure setting and all that changed was the poi. I didn’t use the chrony as with these results it just doesn’t matter.
I’ll keep testing but the best results I have had so far was the factory setting of the reg at 2900+psi and the hammer spring ‘out’ 3/4 of a turn. My best groups to date were ragged holes at 50yds with both JSB and H&N 15.89gr pellets. I have shot a similar target at 75yds with the JSB’s but the flyer always appears.
I know you are testing also and just wanted to share my results.
Tom
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Just to keep it factual it seems after measuring target results that I told you wrong from first impressions. It turns out the the 34gr H&N slugs shot the best 8 shot group at 75yds with 1.35” with a 1.95” flyer. The best the other two did was 2.290” plus one at 3.650” for the H&N 30gr, and 1.6” with two flyers to 3.8” for the Nielson Specialty 36gr slugs. Still, pretty awful.
Tom
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Thanks Tom for the update. I will testing at 50 and 75 yards as soon as I am able to get to the range. Will post results, right now with the 4th and work commitments looks like it will be next week sometime.
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Tom, was able to get to the range today and do some testing to see if the bbl bushings made any improvement. Tested at 50 yards, still having the same issue, 3 shots touching and 2 flies, one one each side of the 3, the group 11/16". Also tried slugs again, no improvement there. Will pull the bbl and polish and see if that helps the group. I am planning on trying some pesting tomorrow to see if it will be effective out to 50 - 60 yards. Will keep you posted.
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id bet 9 times out of ten if all the orings in a new gun arnt checked one or more is nicked, and also its common to have a set screw 'inside' the tp orings on a barrel that can leak .. throw in a smidge of oil and its a recipe for wildly varying pressure .. its a procress with a new gun really, especially low to mid cost id say, but really no experience with higher end stuff .. other things that usually need attention are around the hammer get it smooth snd clean and the barrel itself needs thr throat deburred and possibly the choke end polished out a bit ...
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Different gun but I had some interesting results in my 22 caliber P35 that might be useful. I've only had it about a month now so I am still figuring it out. I have less than 1000 shots through it. It really likes H&N Barracuda Match pellets, 21.14 grain. At the stock regulator setting it is pushing them out at about 835 fps. That gives me reasonable trajectory but 18 grain JSBs were about 875 fps but their 33 yard accuracy was worse than the H&N so I got some 18 grain H&Ns. This gun doesn't seem to care if they are .551 or .552 head diameter although it shoots them to a little different point of impact.
Anyway, groups with the H&N 18s ranged from 3/16 to 13/16 inch. Only one group was over 1/2 inch. Most groups were at 25 yards but some were at 33 yards. I normally have been attributing groups like that 13/16th one to me and that may be correct. But I've been shooting my P35s exclusively for the last month or two and my groups with the pellets they really like do not vary this much. I have a couple with the 22 that look like they are no larger than a bullet diameter. Most are probably under 1/4 inch at 25 yards. It seems to shoot nice little groups with the Match H&Ns but an occasional flier with the 18s.
Is it possible some of the "fliers" are just an indication our gun doesn't like a particular ammunition very well?
Seems like there are lots of potential causes of fliers including:
1) Damaged pellet (or slug) - including from a magazine that damages them
2) Shooter error
3) Odd wind gust
4) Poorly adjusted Occular with varying eye placement
5) Damaged or poorly machined crown
6) Dirty barrel
7) Damaged/poorly machined lead damaging pellets
8) Pellets our gun doesn't like very much
9) Clipping in shroud or suppressor (usually has a very non subtle impact)
10) Loose action or scope mounting bolts
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There have been many people trying to remove the fliers.
We started a 3D Airgun Works printing group on facebook to address those things and others with our Avengers.
Many people have found like Jason said, polishing the barrels helps, but not everyone has those skills.
Tightening and Loctite every screw you can get to will go a long way as well.
You can buy a 11mm x 13mm x 500mm Carbon fiber sleeve from Amazon for about $15 that will help stiffen the avenger barrel, we have designed tested and printed TPU spacers that hold the barrel or carbon fiber sleeve tight into the shroud with good results.
The spacers are also ventilated to allow the air from the muzzle to use the entire shroud to reduce the sound level.
We also have designed moderators that use a centering system like the Donny adapter, but also have internal and external suppression, but only extend 50mm past the shroud, test by many people have found the design to be on the same level off sound suppression as the Donny Tanto and adapter, but at a fraction of the price, and a lot shorter.
What many people have found is after these modifications there are still some fliers, but a lot less, personally on my Avengers (rifle and bullpup) when I had fliers after these mods, they were my fault.
I had to add a bubble level to realize I was not concentrating and slightly and canting the rifle.
With the bullpup because of the scope height over the barrel, it does not take very much of an angle from vertical to move the pellet 2 inches at 100 yards.
After that realization, what fliers I have are now damaged pellets,
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There have been many people trying to remove the fliers.
We started a 3D Airgun Works printing group on facebook to address those things and others with our Avengers.
Many people have found like Jason said, polishing the barrels helps, but not everyone has those skills.
Tightening and Loctite every screw you can get to will go a long way as well.
You can buy a 11mm x 13mm x 500mm Carbon fiber sleeve from Amazon for about $15 that will help stiffen the avenger barrel, we have designed tested and printed TPU spacers that hold the barrel or carbon fiber sleeve tight into the shroud with good results.
The spacers are also ventilated to allow the air from the muzzle to use the entire shroud to reduce the sound level.
We also have designed moderators that use a centering system like the Donny adapter, but also have internal and external suppression, but only extend 50mm past the shroud, test by many people have found the design to be on the same level off sound suppression as the Donny Tanto and adapter, but at a fraction of the price, and a lot shorter.
What many people have found is after these modifications there are still some fliers, but a lot less, personally on my Avengers (rifle and bullpup) when I had fliers after these mods, they were my fault.
I had to add a bubble level to realize I was not concentrating and slightly and canting the rifle.
With the bullpup because of the scope height over the barrel, it does not take very much of an angle from vertical to move the pellet 2 inches at 100 yards.
After that realization, what fliers I have are now damaged pellets,
Excellent post. I don't own an Avenger, but I'm sure most of this can/will carry over to other platforms as well. Thanks for posting!
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Yes it does, the Umarex origin, and the Nova Vista uses the same parts.
The marauder responded well to the same mods.
None of these are permanent, but they are cheap and work well.
The Stl files are free on the 3D airgun works Facebook page, and the 3D airgun works discord page.
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I have bought the moderator that Ian refers to and it works very well without interfering with accuracy. I have others also but I have settled on this one due to overall rifle length, weight, and effectiveness. I also use the bbl/shroud centering rings and he is correct, the holes in them permit the shroud to help with sound moderation.
Flyers still remain a problem with 3 low to mid priced pcp rifles I am testing in 177, 22, and an Avenger in 25ca. One thing they all have in common is a 75yd limit for good bench rest accuracy. Beyond that I am always disappointed. At 50yds or less holes are usually touching. I am starting to think that I am expecting something that these rifles just aren’t capable of at long range. I sometimes shoot at 3/4” lengths of blackboard chalk poked into a hole in card board at 75yds and always hit at least one out of three or better. Without optics I can’t see that far so maybe these rifles are under respected as they are.
Still I’ll keep trying.
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Duplicate post, sorry
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Tom you can shoot MOA groups all day long at 100 yrds Without having all five shots touch. And Bubba that is Very accurate shooting.
You're being unrealistic partner and under appreciative of the performance you have already achieved from a $300.00 gun. What you are looking for would be more suited to expectations from a custom Thomas build gun or the equivalent. We both know the cash investment
chasing that same dream going that route.
You are already getting performance well above fair expectation considering the price, features, accuracy and power delivered.
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With the right tune, and concentrating, and right pellets, any of the avengers are a sub MOA gun.
With .22&.25 one inch at 100 yds I fps a regular event.
For a $400 gun. Bullpup and wood stock. That’s an amazing feat.
Add the sleeve and stabilizers, and some time polishing the barrel.
These rifles can go toe to toe with the big boys.
On paper the “big guys” will have smaller groups.
But on steel, it’s a hit or miss.
For a $400 gun I will stand there and applaud them all day long..
Ian
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Tom, where did you get the moderator. I would like to try one. I also am going to have to rework the trigger. Made the trigger mods that Jim D had talked about some time ago but, it has become heaver with more travel. I still am going to pull the bbl and polish as you have described. Seems as though some flyers are something we will have to live with.
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Tim,
The silencer came from Buck-Rail airguns.com Its not on his main page but search ‘Avenger’ and you will find it for $24.
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Thanks Tom, I will look at ordering one. Worked on the trigger today, winds are high this afternoon will test it tomorrow and see if there is any improvement.
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Air venturia avenger 25 JSB 25.39, will group 3 shots in 1" or less at a 100 yards, but consistently has 2 flyers out of 5 shots. I am trying to figure out what is causing the flyers. I have tried 2 different scopes, 3 different pellets, the same results. Wondering if the regulator could be the issue. Regulator is set at 2100 psi, fill to 3300 psi. All pellets out of the same tin. Any insight would be appreciated.
Are the fliers all ending up in the same area, like they are grouping together? Or are they random?
100 yards gives alot of time in flight to be affected by wind and even pellet deformation. Most guys shoot slugs that distance to counter those issues. Have you tried shooting closer to see how it groups. I would try 30 yards, then 50, to see if it repeats itself.
This is one of the best discussions on accuracy and tuning I've found so far. Well worth the time and effort to watch and listen to IMO. link; https://www.youtube.com/watch?v=xzDjjfYvYXc (https://www.youtube.com/watch?v=xzDjjfYvYXc)
Thanks for posting the video. It's now in my Favorites! Especially since I just got a new to me FX Wildcat MK I.
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Tim,
The silencer came from Buck-Rail airguns.com Its not on his main page but search ‘Avenger’ and you will find it for $24.
I have a very recently purchased Moderator from Buck Rail. It extends 4" past the front end of the shroud and threads into the female threads
in the shroud. You can have it if you like. I've replaced it with one that simply has a approx. 1/8" lip which butts up against the front of the shroud. It has 4 rows of baffles, doesn't extend the length of the rifle at all, easily screws on and off and performs better. In fact it performs perhaps a bit better than the other mono core I had on the gun (and still do on my other Avenger) and goes on, and comes off much easier.
I've already ordered a second one for the other Avenger from E-Bay. Over time I've tried 3 different mono core moderators and this one gets top marks from me.
https://www.ebay.com/itm/125134087158?var=426189370310 (https://www.ebay.com/itm/125134087158?var=426189370310)
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Jerry, Thanks for the information on the moderator. I have the Donny FL SUMO and adapter, but, it extends the bbl about 7". Looks like a sniper weapon with the can on the front. Like the idea of not extending the muzzle. Did test the trigger mod. Improved group with fx 25.4.
35 yards group 4 shots 3/16" 5 shot opened group to 3/8"
50 yards 7/16", at 75 yards 6 shot group 2-13/16".
I shot a second group at 75 yards with jsb 25.39 and that grouped at 13/16". Can't get the scope to clear at 75 yards. May have to replace for targets past 50 yards.
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Looks like moderators are important to others also so let me post what is the quietest one of all on my 25cal Avenger. First my shroud has a 1/8” hole drilled at the breech end with 4 Mr. Clean fitted wads covering it, followed with the aftermarket vented shroud centering rings and the muzzle is capped with my aftermarket stripper. Then baffles to fill the shroud to the shroud end finished with the Donnyfl thread adapter. As it is threaded 1/2X20 and the most effective moderator I used is threaded 1/2”X28” you will need to buy another adapter as used on AR-15’s to make it fit. This will increase the length of your rifle by another 1” but if sound reduction is your major goal try this. For $3.84 the Chinese high quality anodized aluminum ‘fuel filter’ can be drilled out to fit your caliber, and this combo @ 78decibles has proven best. Still, for all around practical use I have settled on the Buck-Rail suppressor. Terry is great to work with.
FYI
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Use your own judgment, but if you have any powder burners, I would steer clear of anything on my airgun that is threaded 1/2x28.
And those Chinese metal things are on the radar of the 3 letter and a badge people..
There is a term they use called “intent”…..
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Good point, but the problem is the other way around. I can’t advise others but I have ATF tax stamps for the powder burners and as far as the air powered rifles are concerned a fuel filter might as well be a hair curler. Still this continues to be a concern to pay attention to. There is a fine line to follow to stay legal.
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This is in no way legal advice, just my opinion, and my level of common sense.
Since you have a stamp for each removable powder burner thingy that is threaded 1/2x28.
Why would someone want to have an unregistered metal 1/2x28 thingy in their possession?
I doubt they would take the owners word that “oh, that one is for the airguns only…..”
There is a reason that 1/2x20 has become the airgun standard threading.
People that have ordered the metal “filter” have received letters requesting they be surrendered, and a few have claimed to have been visited.
Since it was ordered online, by a credit/debit card, and delivered to an address through the mail, there is a trail to follow.
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My take?
Somehow we've taken an informative thread about flyers in a .25 cal airgun, which is well within the scope and intent of this forum, and turned into a discussion on silencers and PB guns.
It's my understanding that from the very beginning both of these topics were discouraged from being discussed on our forum so as not to attract unwanted attention to our little airgun community.
Has that changed?
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I apologize for that, I realize it has gone farther than it should have.
The Avenger is a new gun, and many new shooters have come into the airgun community recently.
I wanted to clarify something that was suggested that should not have been.
I will shorten it to say “I don’t think it’s a good idea to attach anything to the end of an airgun that is not the factory threading for that airgun…..”
Again, I apologize.
Ian
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LOL... you're fine Ian.
Good info is good info.
Along those lines, some of our newer members may not be fully aware of our forum rules and a reminder now and then is probably a good thing... ;)
There are underlying reasons behind some of our rules and understanding some of them may help.
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Well a lot of questions many of us have and raised involving the topic of this thread have found both cause and resolution.
While these answers however came about while directed at FX guns rather than the Avenger. Tom and Timmy will be particularly interested.
I know I was! Well anyway dig around on Youtube for Dubber's new video dealing with the new Power Box, and the "Barrel Tensioner"
I say again, the "Barrel Tensioner". It's a somewhat long vid but well worth it. The solution to bumping and banging a floating barrel and losing
POI comes to light. Harmonics and tuning them fades greatly in importance. View partners and much will be revealed.
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Jerry thanks for the heads up on the video. I will try to find it and give it a look. I add the Mr clean pads and drilled holes for the exhaust of the pressure. This really helped the SUMO but, I am having inconsistent groups. First 5 shot group is 1/4" C to C, 2nd group opens up to 1", at 35 yards. I am thinking it may be something to do with the bbl/shroud bushing. Will remove the bushings to see what change it makes.
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I plan to watch the new bbl. tensioning video from Matt Dubber tonight. I have watched and respect all of his videos. I have ideas about how to properly do this with shrouded rifles but I won’t comment until after I see what he has to show. Thanks Jerry, and thanks for centering this important topic as intended, it should help us all with flyers.
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OK, It's a kind of PIA to find so I dug up the video I was talking about so here it is
link; https://www.youtube.com/watch?v=RBGNA4Tn6SE (https://www.youtube.com/watch?v=RBGNA4Tn6SE)
there is also one short one that centers on the FX Dreamline and a very simple yet effective tensioner and deadener buy swapping out the barrel shroud and cutting the right sized 3mm wall Carbon fiber tubing and two simple spacers (thick washers) and utilizing the Dony Fl can
to take up slack and apply tension. With an extra 100mm extra length with my .25 Dreamline this is a welcome idea when the inevitable happens and I convert to a tactical chasse and convert to a bottle. Here's the link to that video (pretty short)
link; https://www.youtube.com/watch?v=n4nu-77SZg0&t=1s (https://www.youtube.com/watch?v=n4nu-77SZg0&t=1s)
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After watching the videos the principle of bbl tensioning is what I always thought it was. Tension is the proper step to take. You can make the bbl as centered and rigid in the shroud as you can but if it isn’t anchored from the muzzle to the receiver under tension it’s not going to overcome flex, vibration, or probably harmonics.
Let me be long winded for a minute and go way back to 1968 for comparison when I was shooting long range pistols, it applies to pcp rifles now. Bbl. to frame tension was understood back then and it was the company ‘Dan Wesson’ that built a commercial 357mag target revolver with a tensioned shroud that slid over the bbl. up against the frame with a threaded nut at the tip of the muzzle. When proper torque was applied to the nut at the muzzle the bbl. Was anchored and to some degree ‘stretched’ from the frame and harmonics and bbl. “Whip” was eliminated. Accuracy was greatly improved compared to Colt and S&W target revolvers of the day. While 500yds is way out of range for a 357 pistol some impressive hits were made in artillery style with that revolver at that distance that equaled the bigger caliber hand guns and some rifles. Just sayin..
Here is what I think when it comes to applying this principle to pcp rifles. It works and is the proper next step for greater accuracy. But, a problem I see that needs to be overcome in the future is the soft materials used in the construction of these rifles like aluminum alloy receivers and aluminum or carbon fiber shrouds that have a lot of ‘give’ compared to their steel bbls. But as that’s what we now have to work with I still think it’s an improvement and the right step to take.
The best accuracy I ever got from my 25cal Avenger was when I taped the muzzle with electrical tape and forced my Donnyfl muzzle extender against it under pressure.
It didn’t last long as everything was flexible but it showed that I was on the right track.
An optimal pcp bench rifle should have a steel receiver, and whether tapered or not at least a 3/4” OD bbl. With a heavy tensioned steel shroud. The bbl MUST or at least should be anchored with fine threads and fitted tightly to the receiver. But there’s no reason that a lesser version in a lighter sporting rifle couldn’t be made.
We live in good times when it comes to these pcp rifles.
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This may not be a cure, but more of a work around.
https://youtu.be/YaKC36ByKvQ
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" An optimal pcp bench rifle should have a steel receiver, and whether tapered or not at least a 3/4” OD bbl. With a heavy tensioned steel shroud. The bbl MUST or at least should be anchored with fine threads and fitted tightly to the receiver. But there’s no reason that a lesser version in a lighter sporting rifle couldn’t be made."
Yes and optimally a heavy bench rifle will deliver the best (and awesome) results. At 70 now I've been a air rifle devote' from about 10 on and
the last 6 years have really been a epic improvement in air arms. For me getting a Sheridan was huge.
Ok, Some extra benefits was a big improvement in stabilizing POI. I'm clumsy and have a real inborn talent for whacking the barrels on my Avengers. In the Field, if there was one lone 10 yr old popple in a 1/2 acre meadow and i had to cross it? Yes, I'd manage to smack my gun's muzzle into that tree.
So I'd guess it wouldn't take too much to set up a tensioner utilizing the OEM shroud/s. The newer Avengers with the fine threads at both ends of the barrel shroud seem to have an advantage over the original design.
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Tom & Jerryy, I viewed the Dubber video about the tensioning. It was very interesting and informative. My avenger shroud is threaded at both ends. I also have the Donny FL a70 adapter, extends over the bbl.I am wondering if the carbon fiber sleeve that Ian was referring to would stiffen the bbl. I have the swede aluminum rear bbl stabilizer. The carbon fiber sleeve fit against the aluminum rear bbl stabilizer, screw shroud on rear bbl stabilizer. Cut the carbon fiber sleeve so when the Donny FL adapter is tighten down it would put pressure on the carbon fiber sleeve, which should put tension on the shroud. Wondering if I am missing something. The original bbl bushing wouldn't work as the the 13mm od carbon fiber sleeve. Any insight would be appreciated.
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See, that was what i was hinting at when I brought up the double threaded ends on the shrouds. A thrust washer would be a good idea rather than forcing a thin metal edge into the receiver wall. Perhaps even padding the ends with some rubber or silicone washer. It would protect and give a bit of leeway when tightening and that fine pitch thread is going to produce more mechanical advantage than you think or need. Easy does it when tightening.
Right now I'm just spit balling and haven't come up with anything that I'd act on. The Avenger and the FX are 2 different guns and 2 different setups. Three actually because of the 2 different attachments at the rear of the shroud on the old and newer Avenger. BTW using a Q-tip to apply a smidge of silicone grease on those fine pitch threads might be a good idea particularly since it may be mating with threaded plastic.
I've got a cardio procedure today so I'm a bit distracted and "She Who Must Be Obeyed" is on me like a bad habit to get moving.
To be continued!
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Jerryy, sorry you are having to deal with a cardio procedure. We seem to have these interruptions as we move a long. I appreciate your insight and thoughts. I was thinking of using a shroud centering bushings one at the rear and front of the carbon fiber sleeve. I like the idea of a softer washer to give the cushioning you referred to. Ordered the carbon fiber sleeve today. In the interim I will be looking for some washer. I also am thinking about using a o ring between the front shroud centering bushing and the end of the Donny FL adapter, hope would be the bbl would center in the adapter. Hope you are feeling better soon and feel free to give any thoughts are ideas you have.
Thanks again Tim
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Thanks for the kind words Tim. The fiber optic camera showed no serious damage or scarring to the lower heart chambers so that was great and that's one on the good side.
So i just took a squint at my Avenger. It looks like there's already a tensioner built in. One way or another the barrel shroud is secured to the face of the receiver. Both of mine by a Alum. aftermarket barrel bushing that centers the barrel and secures it to the receiver. Newer models are secured to the receiver by threads cut into the shroud itself. Perhaps a bit more advantageous but either will work. Here it is, Ready? Tighten the threaded end bushing. That's it, you might need to add a silicone washer/spacer so there is enough take up that when screwed down tightly the end of the barrel will be butted against the shoulder of the mono core suppressor or a DonyFl adapter.
Lubing mating surfaces with silicone grease should help keep the adapter, end cap. or monocore from torqueing the barrel end out of center.
A metal end cap for the shroud machined square, centered and square would be better than the OEM plastic. Fabricating a thin flat, smooth washer (metal) inside the endcap. Basically We don't need to by anything but perhaps a lone washer (if you chose) and a couple more mounting screws to better lock the end of the barrel shroud in place on the receiver mounting bushing (older model Avengers) . I do have enough crush on my .25 cal gun that I could tighten down on the barrel pretty well. It made a difference. You can feel that shroud stiffen up
and tell that it and the barrel inside are more rigid. The barrel, receiver connection aren't flopping back and forth like Roy Rodgers on Trigger. Another thing, I believe prior measures we were playing with like the centering/deadening
barrel rings should only be a benefit. I'll know more tomorrow. I was thinking about converting a weaver ring base into a removable anchor point for threaded tensioning rods but then the mists parted and I saw all that's needed is pretty much already there. I'm going to find out soon one way or another.
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We seem to all be on the same page as for the need to stabilize the bbl within the shroud. As these pcp rifles all have pencil thin bbls it seems very important.
Two different principles seem to be involved here, pressure or tension, and I don’t care which one works so long as it anchors the bbl. The later Avenger rifles like Tim’s have the threaded plastic reciever block at the muzzle end and that end of the shroud snugs up to it with threads. A problem would be first that its plastic and second only secured by grub screws but that is what we have to work with for now. But for now not trying to make it perfect it’s a decent starting place to try applying ‘pressure’ along the bbl from muzzle to receiver.
Pressure:
1) must be constant so no soft or flexible components could be used as I see it.
2) the Donnyfl extender can be modified and used with spacers and/or metal washers to push against the muzzle tip to cause ‘pressure’ against the whole length of the bbl.
3) this would only be effective up to the shroud receiver block at the breech end as the bbl still is only anchored in a sloppy fitted receiver hole by grub screws. But it still might work.
Tension:
1) this is what I think may work best and will require the muzzle end of the bbl to be machined and threaded to accept a proper shroud extender that is also threaded and a cap that is unthreaded to the shroud. Now when the shroud cap is torqued down it will draw ‘tension’ the full length of the bbl and the shroud.
2) unfortunately this still leaves the slop in the bbl mounted within the receiver as well as the slop where the shroud screws on to its receiving block. Grub screws really aren’t up to the job.
3) if this setup shows promise a threaded bbl to the receiver should be needed. Also the shroud should need to attach directly to the receiver and not to a slide on mounting block.
Boy am I with you regarding the Sheridan! I bought mine new around 1963 and the factory has rebuilt it twice, it still works great. Prior to that I wore out a Crosman M-160 22cal and would like to buy another just to have.
I hear you Jerry about the cardio procedure, and I wish you well. Sometimes our other half's efforts are a needed push. I have been through the hoops and am very disappointed with the ‘one size fits all’ care you get when you become a senior, the next time the medical profession sees me again will be feet first. Best wishes.
Tom
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Tom and Jerryy, l think that the tension method would be best as Tom describe but, without the steel receiver I don't see that will work.
My Donny FL a70 adapter slides over the bbl and doesn't have a step to apply force against the bbl, same with my monocore. I used the original baffel that came with the avenger. It has a 1/2" space between it and the bbl. I made a spacer of brass tube to fill the gap and added a plastic washer to each end, tighten down as tight as I could by hand. Did a 5 shot groug.at 23 yards group was 5/8". Removed spacer and washers and shot another 5 shot group of 5/16", same pellets and distance. Please give me any thoughts.
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Tom and Jerryy, l think that the tension method would be best as Tom describe but, without the steel receiver I don't see that will work.
My Donny FL a70 adapter slides over the bbl and doesn't have a step to apply force against the bbl, same with my monocore. I used the original baffel that came with the avenger. It has a 1/2" space between it and the bbl. I made a spacer of brass tube to fill the gap and added a plastic washer to each end, tighten down as tight as I could by hand. Did a 5 shot groug.at 23 yards group was 5/8". Removed spacer and washers and shot another 5 shot group of 5/16", same pellets and distance. Please give me any thoughts.
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Tom and Jerryy, l think that the tension method would be best as Tom describe but, without the steel receiver I don't see that will work.
My Donny FL a70 adapter slides over the bbl and doesn't have a step to apply force against the bbl, same with my monocore. I used the original baffel that came with the avenger. It has a 1/2" space between it and the bbl. I made a spacer of brass tube to fill the gap and added a plastic washer to each end, tighten down as tight as I could by hand. Did a 5 shot groug.at 23 yards group was 5/8". Removed spacer and washers and shot another 5 shot group of 5/16", same pellets and distance. Please give me any thoughts.
Perhaps too much pressure and the barrel shifted position a wee bit. Too much pressure might induce a tiny bit of bowing by the barrel too. The lack of a solid, accurately machined metal face on the Avenger receiver's face is going to be a real problem. Utilizing the machined,
straight and parallel scope rails might be of use but it will jazz up alignment and bolt probe depth so offhand that's a dead end.
A good friend of mine has been shooting since he stood waist high and precision and extreme distance bench rest is his specialty.
He and his wife also have been very dedicated air rifle shooters. Some here may know him as Pbike257. His hot setup for extreme accuracy at long distance was positioning o=rings at even distance along the barrel of one of his MKII Impacts and E-epoxying in the opposite ends so they are imbedded in the barrel shroud at both ends and in proper position. I think he may of mentioned doing the same thing to a .30 cal
also.
Tensioning may not require a solid metal face in the Avenger. We are not pushing against the receiver's face. We are pulling against the threads that I assume are cut square, centered and parallel. The receiver face does not come into play. As long as the threads at both ends
are accurately cute in alignment then it's a matter of figuring a way to use the threads on the front end of the shroud to "draw" the shroud away from the receiver and establishing tension. And this ever working long term would depend a lot on the threads being strong enough and holding up.
Nope I don't see "tensioning" working on the Avenger. Now pushing back on the front end of the barrel? Yes, the old style receiver/shroud barrel mounting bushing supplies a flat, hopefully sufficiently square face. the applied force is pushing into the metal flange which is butted against the receiver. If the barrel is centered in the shroud along it's entire length and the muzzle end remains centered in the Dony adapter that baby should do the job. But the receiver end of the shroud Should Not Be fixed in place on the mounting bushing!
It has to be able to slide over the mounting bushing, Double threaded shrouds would first need to be screwed in at the receiver end tight enough by hand putting pressure on the barrel mounting bushing. Then utilizing the front threads turn in the shroud end cap, mono core moderator if it screws into the shroud. Might need a thin washer to give a little more squeeze to the arrangement but a firm tightening and you should have it. Remember firm but not turn it in till the threads start stripping then give it another half turn. Firm not crazy tight.
turning in the receiver end threads of the shroud sets up the squeeze initially and tightening the muzzle cap, Dony adapter, or outside can type moderator, continues to apply force through the barrel and clear into the receiver.
Best I could come up with so far but using set screws to lock shroud in tightened position when using threads on the shroud itself is PIA due
to the rotation of the tube when tightening and loosening using the threaded ends. You just can't slot the holes lengthwise. NUTS!
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Jerryy, thanks for the information. I agree that pressure is the right approach on the avenger. Currently the original bbl bushing the screws into bore end of the shroud has a 1/2" space between it and the bbl. The brass spacer and 2 rubber washers were aligned with a wooden dowel and held in place only by pressure of the original bbl bushing. MY concern is if any tension is released these parts will shift and create an issue. The Donny FL slides over the bbl and is smooth on the inside, I can't see away for it to put pressure on the bbl. Same issue with the monocore. If there was some band too attach to the bbl so as the Donny FL could put pressure on it, that might accomplish the goal. It seems like FX did something similar to the bbl clamp on their tensioning system.
I have ordered the fiber carbon sleeve that will slide over the bbl. I hope to cut it to the proper length so that the Donny FL adapter or the monocore will put pressure on the carbon fiber sleeve by screwing the adapter down as you described. My hope is it will put pressure on the shroud and stabilize the bbl.
Thanks Tim
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Jerryy, thanks for the information. I agree that pressure is the right approach on the avenger. Currently the original bbl bushing the screws into bore end of the shroud has a 1/2" space between it and the bbl. The brass spacer and 2 rubber washers were aligned with a wooden dowel and held in place only by pressure of the original bbl bushing. MY concern is if any tension is released these parts will shift and create an issue. The Donny FL slides over the bbl and is smooth on the inside, I can't see away for it to put pressure on the bbl. Same issue with the monocore. If there was some band too attach to the bbl so as the Donny FL could put pressure on it, that might accomplish the goal. It seems like FX did something similar to the bbl clamp on their tensioning system.
I have ordered the fiber carbon sleeve that will slide over the bbl. I hope to cut it to the proper length so that the Donny FL adapter or the monocore will put pressure on the carbon fiber sleeve by screwing the adapter down as you described. My hope is it will put pressure on the shroud and stabilize the bbl.
Thanks Tim
Don't mention it Tim. I'm enjoying the brainstorming, honestly and there are some pretty sharp minds here to engage with.
I re-read my last post and saw that I got tangled up. I apologize. I'm a lousy typist and at times the mind is working (for better or for worse)
faster than then my traitorous little piddies perform. The end result sometimes look like it was written during a 3 day drunk. I'm grateful
to you, Tom and the other people following this thread for your patience and courtesy.
Employing spacers and thrust washers might be helped to stay in position by machining very shallow counter bores. I'd consider even
cutting in slight shallow angles in the inside corners right to or even slightly deeper than the bottom face of the pocket. This could help self align the mating parts. The fit of parts like the Mono core or Dony adapter that slide over the barrel itself kind of concerns me. Also the concentricity of the barrel deadening and centering bushings as well. Doing final fitting with a rat tail file on plastic and keepind it round and centered that way could be a craps shoot. Me being without much in the way of machine tools, would opt for a whip stick.(round metal rod
with a sawed slot cut lengthwise in one end to hold emery strip folded over evenly and rolled partially around each side of the slot. These should not be so long that the ends overlap themselves. It is basically a flapper wheel. Centrifugal force pushes the ends of the emery strips
against the sides as it is moved in back and forth inside the center hole of the bushings. It will bell mouth the bore near the openings but the sides should remain centered. Fine grit emery will likely not be aggressive in stock removal so it shouldn't be very hard to sneak up on a nice
sized fit.
One other thing I noticed when I first checked out my first Avenger was that the Soft plastic center bushing that is OEM and designed by Venturi is not completely concentric. At least mine was not. I took the barrel and set up a pair of matching precision V blocks and a surface gage and indicator. The OD on both ends that are grooved for O-rings and fit snugly in the bore of the shroud were concentric spot on! the OD of the part between the O-rings was not and extended well past the outer diameter of the O-rings so one side of this bushing was being compressed and pushing against the inside wall of the shroud while the other side was not. I shaved these high areas down before I re-reassembled the gun. Also make sure the set screw in the side of this bushing isn't making contact with the inside of the shroud.
That was my gun and others may not have that problem but I thought I'd bring it up.
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I'm amazed with the inventiveness discussed in this thread. I'm skeptical about a tensioned barrel for the Avenger because I don't think the receiver can secure the barrel well enough. I also think the need for a tensioned barrel is much less on an Avenger than it is on a FX because the barrel diameter of the FX is much smaller. Their rifling is pressed in from the outside necessitating a really thin barrel. But if you look at just about any shooting competition you will find FX rifles so they obviously shoot great.
I'd love to see a simpler potential "solution". I'd like to have a barrel support that would fit snugly over the barrel with a groove for an O-ring to fit snugly in the shroud. My P-35s have an aluminum piece that screws into the end of the barrel with the O-ring for the shroud. But it seems simpler to not try and attach this, threading the barrel would not be easy, that firmly. The goal would be to ensure concentricity and to reduce the magnitude of barrel vibrations. A plastic printed piece should be accurate enough, probably with a barrel hole drilled to final size. It could also be secured by an O-ring or two, however.
Tensioning the barrel makes a thinner barrel act more like a thicker barrel from a vibration standpoint. I think an Avenger barrel is thick enough it doesn't really need to be tensioned but I think it is poorly supported. A grub screw at the receiver and a poor fitting plastic disk in the shroud is not a great system of support. I think even a better designed plastic support piece would be a potentially significant improvement.
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I'm just grateful I don't have the accuracy issues seen in this thread with my .25 Avengers. It's one of the most accurate guns I own.
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It already exists. It's discussed earlier on in this thread. Thick coin like baffles that are radially grooved on the outside for O-rings and
have a center hole to fit snugly on the barrel. You get a set of 4. There is a video on installation.
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Yes it does, the Umarex origin, and the Nova Vista uses the same parts.
The marauder responded well to the same mods.
None of these are permanent, but they are cheap and work well.
The Stl files are free on the 3D airgun works Facebook page, and the 3D airgun works discord page.
The Seneca Aspen uses the same (and very accurate) barrels though it's a bit shorter in length than the Avenger, Shroud OD/ID is also the same
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I'm amazed with the inventiveness discussed in this thread. I'm skeptical about a tensioned barrel for the Avenger because I don't think the receiver can secure the barrel well enough. I also think the need for a tensioned barrel is much less on an Avenger than it is on a FX because the barrel diameter of the FX is much smaller. Their rifling is pressed in from the outside necessitating a really thin barrel. But if you look at just about any shooting competition you will find FX rifles so they obviously shoot great.
I'd love to see a simpler potential "solution". I'd like to have a barrel support that would fit snugly over the barrel with a groove for an O-ring to fit snugly in the shroud. My P-35s have an aluminum piece that screws into the end of the barrel with the O-ring for the shroud. But it seems simpler to not try and attach this, threading the barrel would not be easy, that firmly. The goal would be to ensure concentricity and to reduce the magnitude of barrel vibrations. A plastic printed piece should be accurate enough, probably with a barrel hole drilled to final size. It could also be secured by an O-ring or two, however.
Tensioning the barrel makes a thinner barrel act more like a thicker barrel from a vibration standpoint. I think an Avenger barrel is thick enough it doesn't really need to be tensioned but I think it is poorly supported. A grub screw at the receiver and a poor fitting plastic disk in the shroud is not a great system of support. I think even a better designed plastic support piece would be a potentially significant improvement.
I agree Jim, I originally thought more along the lines of a say 2" bushing with 2 O-rings, one at each end and would use 2 to three on the barrel. This mono core suppressor fits the ID of the shroud perfectly. the outer grooves would need to be extended through one end and the groves deepened under the O-rings. If simply machined with a straight bore clear through and perhaps relieved a bit for some of the lenght in it's center (just to make machining easier) and a ID O-ring at each end to insure a tight fit on the outside of the barrel we'd be styling baby! Of course it could be made 1" to 1/1/4" shorter. Here's a link to the Mono Core suppressor just to give us all an idea of what I'm talking about. Centering the barrel, Stiffening it, and Harmonics deadening? What do you think?
Link; https://www.ebay.com/itm/333889982140 (https://www.ebay.com/itm/333889982140)
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@JimD
Not quite sure what length or where in the barrel you want the support...at the rear? Full length? At the front?
The rear is doable, I made a better rear bushing, with oring groove, printed plastic with imbedded nuts so all the screws are biting into metal threads, not plastic. Even my cheap printer can print to the 0.1mm or better, so drilling the center out does not seem necessary.
Could be modified to fit anywhere in the shroud, but I can't print much longer than 10" at a time. At the front too far would interfere with LDC fit, so I'm only using the stock barrel-shroud centering thing up there. It seems to fit very well on mine -- that oring feels just tight enough when sliding the shroud over it.
Also too much "stuff" in the shroud may lessen the noise dampening it provides, especially if so solid that air cannot pass back towards the receiver end...
EDIT -- whoops I missed a few messages before posting this, but the spacers Spin describes would be very simple to design and print. Could be held to barrel with grub screws , or not... --ENDEDIT
Here's pix of the rear bushing I put on my 22 Avenger:
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This discussion seems very correct, and I have to think that FX bbls are on the right tract and ahead of the rest, but just not quite there yet. My CZ M-527 American rifle in cal 221 Fireball has a bbl that is also cold hammer forged and began with a 1” blank and then tapers to .570” at the muzzle. The only point I wish to make is that with the correct tools and dies any bbl of any size can be cold hammer forged. I wouldn’t even mention it if not for the superior accuracy of this rifle out of the box no matter what the load. Cut and button rifling in lower priced rifles seem to have flaws and runout but have acceptable accuracy for the price point, but I still can’t find a reason to make them pencil thin.
It won’t be me but I expect that some sharp individual will produce a heavier steel tapered bbl threaded to a steel receiver and follow the advances made with the powder burners.
Please don’t miss understand what I am saying about the accuracy of the 25cal Avenger. Of the several rifles that I shot at 75yds today nothing outshot this rifle. It’s hard to argue with hitting 9mm pistol cases at that range. But so long as flyers remain there is room for improvement.
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@JimD
Not quite sure what length or where in the barrel you want the support...at the rear? Full length? At the front?
The rear is doable, I made a better rear bushing, with oring groove, printed plastic with imbedded nuts so all the screws are biting into metal threads, not plastic. Even my cheap printer can print to the 0.1mm or better, so drilling the center out does not seem necessary.
Could be modified to fit anywhere in the shroud, but I can't print much longer than 10" at a time. At the front too far would interfere with LDC fit, so I'm only using the stock barrel-shroud centering thing up there. It seems to fit very well on mine -- that oring feels just tight enough when sliding the shroud over it.
Also too much "stuff" in the shroud may lessen the noise dampening it provides, especially if so solid that air cannot pass back towards the receiver end...
EDIT -- whoops I missed a few messages before posting this, but the spacers Spin describes would be very simple to design and print. Could be held to barrel with grub screws , or not... --ENDEDIT
Here's pix of the rear bushing I put on my 22 Avenger:
At first glance that looks good. A bit shorter than I think would be ideal but just the same a big improvement, But - You need slots
or evenly spaced thru holes through the faces and backs to allow air to move inside the shroud. All the same the venting holes are simple and from there they look like they will get it done alright.
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I'm pretty sure that cold hammer forging is not what FX is doing. Cold hammer forging is placing what is in essence a die inside the bore and then pushing (really hard) on the outside of the barrel so it comforms to the die. I don't think FX puts anything on the inside, they push on the outside. The result of the FX process is a very smooth interior that is about as smooth as the tube they started with but it's rifled. Unless it is polished afterwards, the result of more conventional rifling is not super smooth.
Where the spacer to help support the barrel would have to be determined through testing. A small diameter tube would probably be necessary to keep the spacers that go out to shroud positioned along the barrel length. I'd start with one at the mid point (along with an in shroud moderator I already use and like a lot). But two at 1/3 the length might be better and unequal spacing might also help more. O-rings to contact both the barrel and shroud would be my first choice. I think more physical support for the barrel is potentially significant but I would expect accuracy to be affected more by dampening vibration in the barrel. The O-rings seem like they would be better to dampen vibrations as well as ensure there is fairly uniform contact.
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O-rings would not necessarily be better for dampening vibration. Operating a engine lathe with a 20 ft bed and a 4 ft plus diameter over the ways capacity, almost always machining cylindrical work, vibration and harmonics were a constant problem. Wrapping the OD with live rubber hose did next to nothing. When doing OD machining on such jobs shoveling around 150 to maybe 200 lbs of chips (metal shavings) Into the bore was reasonably effective. Internal boring? Duct taping 25 lb bags of lead shot to the outside of the workpiece was the most used technique. The amount of duct tape that got used on the really big work was really impressive as was the number of bags of shot.
. De-Vibrator boring bars most often employed a bored blind hole that was almost but not quite filled with slightly loose fitting hardened steel washers. Sometimes steel shot was used. On much smaller, shorter work pieces solid carbide boring bars were the ticket though Very expensive. Old timers often took a ballpeen hammer, held it by the very end of the handle and rested the flat contact surface of the hammerhead on the top of the rotating stock that was being turned or bored which usually quelled the harmonics and stopped the workpiece from "singing" and heading off that turning into very serious chatter. Soft bumpers, pads and rings Even wrapping the majority of the cylinder with quite thick rubber sheet and securing it along it's length with heavy gage soft wire and twisting it's ends to tighten it was not at all very effective. Go figure!
The hard weighty materials tended to bleed of the kinetic energy that harmonics gathered and amplified.
That said I still think plastic baffles will serve and O-rings as well but they should be relatively small dia. and lean towards the harder side of the durometer scale as long as they will compress enough that the baffle can be installed and removed without too much effort.
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I'm pretty sure that cold hammer forging is not what FX is doing. Cold hammer forging is placing what is in essence a die inside the bore and then pushing (really hard) on the outside of the barrel so it comforms to the die. I don't think FX puts anything on the inside, they push on the outside. The result of the FX process is a very smooth interior that is about as smooth as the tube they started with but it's rifled. Unless it is polished afterwards, the result of more conventional rifling is not super smooth.
Where the spacer to help support the barrel would have to be determined through testing. A small diameter tube would probably be necessary to keep the spacers that go out to shroud positioned along the barrel length. I'd start with one at the mid point (along with an in shroud moderator I already use and like a lot). But two at 1/3 the length might be better and unequal spacing might also help more. O-rings to contact both the barrel and shroud would be my first choice. I think more physical support for the barrel is potentially significant but I would expect accuracy to be affected more by dampening vibration in the barrel. The O-rings seem like they would be better to dampen vibrations as well as ensure there is fairly uniform contact.
Jim D I'm sorry to have missed stating that while the dimensions and design of the rear barrel mount bushing are quite good
and I'm sure it will work perfectly well centering the barrel and shroud and the clamping arrangement is also excellent I believe that a all metal bushing would be a better choice. Here's why, "hinging"! That juncture where the barrel, shroud and receiver connect is a flex point.
I agree with the guys that brought that to the front earlier in the discussion. All metal as expressed before would be best. Plastic as it was made may still work well, in fact I firmly believe it's a significant improvement over OEM but metal would address compression and stretching which may result in poor rigidity and result in POI shift. This is a decided weakness in the Avengers design also been brought up by more observant people than myself. I really like the extended length of that rear mounting bushing.
I think Tommygun came to that conclusion and I believe he's right.
I hope you don't get PO'd at me, at some point I'd love to buy my way into getting a set of those stiffening baffles from you. ::)
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@Spin
I'm not sure if your above reply was about my redesigned plastic rear bushing -- I think it was. I agree it would be better in metal. I am not a machinist guy, but a 3D printer guy, so I go with what I know. This bushing, in combination with an LDC that centers the muzzle, and a muzzle-end shroud-to-reservoir clamp, has vastly improved my Avenger's problem with POI changes, and somewhat improved groups. I am following this thread with interest, although I don't seem to have unexplained fliers like I used to, I am interested in further reducing group sizes (at 100 yards primarily.)
I suppose it depend how one defines "flier." 4 in an inch, and a 5th that opens it up to 2 inches...flier or just a bum pellet? So much can happen at that distance. I used to routinely get fliers with this gun with CPHPs. I recently did a 20 shot string (at 25 yards) and not a single (indentifiable) flier.
Enjoying this thread and the ideas here, and real world analogies -- what may or may not work well.
Barrel movement / harmonics is on my mind. The effects of thicker barrels, sleeves, bushings, well-placed weights, barrel tensioning or compression all have potential. Expansion of shroud / reservoirs / barrel bands due to pressure and or temperature changes and affect on POI.
I am debating what to try next. Bushings, with or without orings, between barrel and shroud are simple to design and print. I doubt there is much sag to correct, it is already supported at rear, middle-ish and front. I'm not sure just filling the space will help much -- filling it with mass might...
Has anyone used metal or CF that snugly, completely fills the void between barrel and shroud? Did it help?
I'd love to keep the noise reduction of the shroud but lose the bands needed to keep it and the barrel from being floppy. I have ideas on that but not fully formed. The Avenger is low cost, the cast? receiver parts not ideal for adding much stress.
I'm up for printing anything that might help. Shipping costs more than the plastic if anyone has ideas they want to try.
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Hi Bob!
Well there are a couple of videos out where Kinetic Sand was used to fill the space between the outside of the barrel and the inside of the shroud with a well sealing plug in the rear to contain the sand. Then was tamped periodically while filling to "harden"the sand and then the shroud was plugged again leaving several inches un filled at the muzzle end. A clamp style barrel band was installed close to the muzzle and over the unfilled portion of the shroud. No air could flow through the shroud but the results were pretty impressive.
link; https://www.youtube.com/watch?v=JQNRJ5K2_XI (https://www.youtube.com/watch?v=JQNRJ5K2_XI)
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That would not be difficult to reproduce -- the kinetic sand packed into the shroud -- anyone could do it. Did he in a previous video test those pellets with his setup, without the sand? He got great results, just wonder how much of that is due to the sand packing. Also, as is frequently the case, one 4-shot group with each pellet type really isn't enough to prove anything, but it sure looks promising.
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That would not be difficult to reproduce -- the kinetic sand packed into the shroud -- anyone could do it. Did he in a previous video test those pellets with his setup, without the sand? He got great results, just wonder how much of that is due to the sand packing. Also, as is frequently the case, one 4-shot group with each pellet type really isn't enough to prove anything, but it sure looks promising.
I can't say if he did but you can put in a query on YouTube for "Sam Houston's air rifle videos" Remember this may be fine for bench shooting
but it might prove a smidge heavy, especially in the muzzle. Then barrel removal for cleaning is going to be a PIA and you have a gun with a lot of abrasive stuffed inside it. There is a bit of mystery here as to how things are going to go in regards to thermal cycling both performance wise and the plugs containing the grit(and the silica dust from sand can be mighty small)inside the shroud.
I am an avid target shooter but also a serious hunter so my ancient carcass has to hump around and shooting opportunities are frequently offhand. This modification would not suit everyone hence the search for other alternatives. Don't worry we're getting there and it won't be long before one of use get's the Golden Ring. Has making a baffles that has a chamber hollowed out inside it and filled and sealed with kinetic sand inside it? Weights certainly can improve barrel performance. That's well known and Kinetic sand has a unique effect when exposed to impact and vibration.
OK, That's enough thinking for this year. My brain's aching and there's smoke leaking out from my ears.
BTW several references have been made about PB guns and their barrels. For a long time "Bull Barrels" Large, heavy barrels with little or no taper tamed wild harmonics and produced superb results for bench and varmint shooters.
P.S. A gun with a sand deadened barrel arrangement will need a air stripper on it's muzzle.
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I don't own an Avenger but this is what I would do if I did.
Attach a clamp similar to the FX using a tube clamp with a raised lip at the Rx end.
Thread the end of the barrel and make a threaded cap that will tension the barrel.
Use a smaller diameter thick CF barrel shroud that will allow a through bolt for a barrel band.
Most of the parts will have to be custom made but nothing earth shattering.