GTA
Airguns by Make and Model => Diana Airguns => Topic started by: David110 on August 15, 2020, 10:11:51 PM
-
Baracuda 21.14 grains and 5.50 head size, fits smoothly not loose but not tight at all.
H&N FTT 14.66 grains, 5.53, the head "clicks" in to fit then goes in smoothly not crazy tight but tight.
The shooting distance is 14 yards, handheld, sitting, 5 shots each.
I aimed only at the top target for both pellets, as you can see the barracudas shot about 4 to 5 inches low.
I don't have a chrono to check the digits but I made sure the seals are airtight with some caveman tests (half cocking, blocking the air chamber hole with my finger, waiting a few seconds and then feeling the negative/positive pressure cocking/decocking).
Also blowing in the barrel to do a breach seal test. everything is very airtight.
If I compensate those 5 inches my open sights get too loose.
What could be the problem? I was hoping that my magnum would love these heavy grain pellets.
Cheers.
-
Going from ftt to cudas is roughly a30% increase in weight. I would give jsb 16 & 18 gr a chance. 21 gr is a lot to ask of a springer even a powerhouse like the 350. Those ntec guns are nice I hope you will continue to update this post as you shoot more
-
A 5" drop from gravity in only 15 yards with a magnum? I don't think physics would allow this unless something is majorly wrong with the power plant of the rifle.
Unfortunately, JSB is non-existent where I live, I would have to look for inferior brands of pellets like Gamo or BSA to match what the gun can handle.
The gun feels amazing unscoped, I know a scope would allow me to go lower further with the proper droop mount. But I don't believe it had a droop, especially considering this is with iron sights.
Any other ideas?
-
H&N FTT is what I shoot in my 340 N-tec.
You want the pellet to "click-in" and have a snug feel when loading....
-Y
-
Yeah, I was describing the feel of pellet size 5.50 Baracuda vs 5.53 FTT in relation to my particular barrel in case it has something to do with the pellet throw? The barracudas weren't loose at all either.
-
I think it is safe to safe that the 5.50 Barracuda is not the right pellet. ;)
-Y
-
David110,
Its not gravity causing the heavy pellets to drop so much more at such a short range. It may be vibration harmonics, with the muzzle pointing down further when the heavy pellets emerge. You can test that theory by attaching taping something with about the weight of a can of pellets tightly to the barrel just behind the front sight. That may make the problem worse, which case you move the can back two inches and try again.
There are thread on this forum about muzzle weights. Hector Median could probably give you much better advice than to "try something". He has made muzzle weight that are screw adjustable for Diana Air rifles.
Before you do anything else, check to see if any of the stock screws are loose. That is the most likely cause for point of impact problems. How that might affect a heavy VS a light pellet I am not sure, except that it affects corrupted harmonics with extra motion of action in stock.
Is the pellet seating fully in the breech cone? Load a few of the "low" type pellets, but open the breech again before shooting them. Is there any evidence of the skirt making contact with the breech around the transfer port hole? Addressing that is a separate matter. It also raises a few more options n terms of possible ways to affect point of impact - including preventing the breech from fully closing, so the barrel points down.
-
subscriber,
Exactly what I thought re. gravity. It's the spit pattern of the muzzle. I was going to test it tomorrow and hold the rifle gangster style on the side 😂 to see if the pellets still go down or if they go to the right.
When it was scoped I removed the front globe sight, the gun never amazed me with the scope, as soon as I put the open sight back I noticed it puts pellets inside the same hole more often and the group is tighter. I thought it was either the weight of the gun became easier to hold, or the weight of the front sight calmed down the nozzle.
I'll try the weight test you suggested.
And yes, pellets are seated all the way in and I make sure everything is tight after each shooting session, so that's not a problem.
-
I was going to test it tomorrow and hold the rifle gangster style on the side 😂 to see if the pellets still go down or if they go to the right.
Brilliant. Why didn't I think of that :)
-
Confirmed. The side hold made the pellet fly to the right.
Next, I'll test the cudas with a different head size, I think the shop has the match in 5.52 or 3.
I hope that works because I really don't want to add anything to the gun like a muzzle weight.
-
That simple test is telling, David.
Tuned muzzle mass harmonic devices are not that complicated. I remember posts on this forum by Hector Medina specifically for Diana (RWS) models, and am still looking: Meanwhile I found pertinent info on spring airgun harmonics: https://www.ctcustomairguns.com/hectors-airgun-blog/truly-taming-the-harmonics-in-spring-piston-airguns (https://www.ctcustomairguns.com/hectors-airgun-blog/truly-taming-the-harmonics-in-spring-piston-airguns)
A lot more discussion at the links below.
Springer barrel vibration:
https://youtu.be/FaW_Hs0B79c (https://youtu.be/FaW_Hs0B79c)
https://www.gatewaytoairguns.org/GTA/index.php?topic=134643.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=134643.0)
(http://i378.photobucket.com/albums/oo221/rsterne/177%20PCP%20HFT/MuzzleWeights.jpg)
https://www.gatewaytoairguns.org/GTA/index.php?topic=111946.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=111946.0)
https://www.gatewaytoairguns.org/GTA/index.php?topic=12693.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=12693.0)
https://www.gatewaytoairguns.org/GTA/index.php?topic=12693.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=12693.0)
https://www.gatewaytoairguns.org/GTA/index.php?topic=121751.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=121751.0)
https://www.pyramydair.com/blog/2008/10/a-harmonic-tuning-muzzlebrake/ (https://www.pyramydair.com/blog/2008/10/a-harmonic-tuning-muzzlebrake/)
Scroll down: https://airgunwarriors.com/community/postid/34428/ (https://airgunwarriors.com/community/postid/34428/)
(https://airgunwarriors.com/wp-content/uploads/wpforo/attachments/2311/14874-Vortek-Accuracy-Tamer-001.JPG)
-
What about sleeving the barrel with a carbon fiber tube, does this help? I'm trying to think of available/easy fixes first. The weights probably can't be shipped here without a firearms license.
-
What about sleeving the barrel with a carbon fiber tube, does this help?
Absolutely. Anything you do to alter the vibration can make it better. However, it can also make it worse. Generally, the stiffer the barrel the higher it resonant frequency, and the smaller the vibrational amplitude.
Some of the thread links above include carbon fiber sleeving, although a search specifically for that will show tensioned sleeve barrels - the holy grail. Will find some and post links to that...
-
A barrel weight is easier to apply and easier to remove;
but here is plenty of carbon fiber barrel sleeve info and discussion:
https://www.gatewaytoairguns.org/GTA/index.php?topic=80600.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=80600.0)
https://www.gatewaytoairguns.org/GTA/index.php?topic=71756.msg683790#msg683790 (https://www.gatewaytoairguns.org/GTA/index.php?topic=71756.msg683790#msg683790)
https://www.gatewaytoairguns.org/GTA/index.php?topic=83403.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=83403.0)
https://www.gatewaytoairguns.org/GTA/index.php?topic=154337.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=154337.0)
https://www.gatewaytoairguns.org/GTA/index.php?topic=174653.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=174653.0)
https://www.gatewaytoairguns.org/GTA/index.php?topic=68666.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=68666.0)
https://www.google.com/search?q=site%3Awww.gatewaytoairguns.org+carbon+fiber+sleeving&tbm=isch&ved=2ahUKEwi_xJv83qHrAhWrAzQIHZy8DkYQ2-cCegQIABAA&oq=site%3Awww.gatewaytoairguns.org+carbon+fiber+sleeving&gs_lcp=CgNpbWcQA1CRYVivkAFg2ZUBaABwAHgBgAG6AYgB6QySAQQyMC4xmAEAoAEBqgELZ3dzLXdpei1pbWfAAQE&sclient=img&ei=SDU6X7-AFKuH0PEPnPm6sAQ&bih=533&biw=1117&rlz=1C1NDCM_enUS793US793 (https://www.google.com/search?q=site%3Awww.gatewaytoairguns.org+carbon+fiber+sleeving&tbm=isch&ved=2ahUKEwi_xJv83qHrAhWrAzQIHZy8DkYQ2-cCegQIABAA&oq=site%3Awww.gatewaytoairguns.org+carbon+fiber+sleeving&gs_lcp=CgNpbWcQA1CRYVivkAFg2ZUBaABwAHgBgAG6AYgB6QySAQQyMC4xmAEAoAEBqgELZ3dzLXdpei1pbWfAAQE&sclient=img&ei=SDU6X7-AFKuH0PEPnPm6sAQ&bih=533&biw=1117&rlz=1C1NDCM_enUS793US793)
-
Thanks, subscriber, this is a wealth of info and a lot to play with. I'll update as I figure it out.
-
Baracuda 21.14 grains and 5.50 head size, fits smoothly not loose but not tight at all.
H&N FTT 14.66 grains, 5.53, the head "clicks" in to fit then goes in smoothly not crazy tight but tight.
The shooting distance is 14 yards, handheld, sitting, 5 shots each.
I aimed only at the top target for both pellets, as you can see the barracudas shot about 4 to 5 inches low.
I don't have a chrono to check the digits but I made sure the seals are airtight with some caveman tests (half cocking, blocking the air chamber hole with my finger, waiting a few seconds and then feeling the negative/positive pressure cocking/decocking).
Also blowing in the barrel to do a breach seal test. everything is very airtight.
If I compensate those 5 inches my open sights get too loose.
What could be the problem? I was hoping that my magnum would love these heavy grain pellets.
Cheers.
Kia Ora!
David, DIANA barrels are usually on the large end for 0.177" but "tight" on the 0.22".
I would try a number of pellets, while JSB's are reilable, some guns do prefer Crosman, RWS's, and SOME H&N, in a "Night hunter" I am preparing (complete with night-vision optics), I am not having ANY luck with Baracudas, but the JSB's in lead and tin are one-holers, and the Crow Magnum's out to about 30 yards are good enough for hunting raccoon sized critters (about the size of your Possum).
¿Have you tried loading a Baracuda, then closing the barrel and then opening the breech again? That shot pattern seems to indicate skirt deformation upon closing the breech, as well as a breech that does not fully closes.
Besides, it really all depends WHAT you want to do with the gun, the task defines the projectile.
The 350 NTec has enough energy to make the real expanding pellets expand (Predators, CrowMags, Super H Points). Crosman HP's are not truly expanding pellets, but because of HOW they are made, they are usually more accurate than the domed heads. And, after all, a 0.22" hole is still an 0.22" hole.
Since the muzzle weight is, essentially, a hollow tube (in the case of the 350, it needs a bit of a design change), I don't see why it should be stopped at Customs. BUT a well made HT does need a completely cylindrical barrel and I am not sure yours is.
AFAIK piston airguns are not regulated in NZ, so accessories shouldn't be either. But the law may have changed since I was there in 2014.
Do the closing without firing test and let us know what happens.
HM
-
A suggestion before you start making barrel weights, sleeves, harmonic stabilizers etc.
Wrap a length of solder around the end of the barrel to see what the impact on group size and position is. Tape it in place with painter's tape. Shoot a couple groups, move it back a couple mm or so retake and try again. Shoot a couple groups. continue until you see something or not.
That way you won't get much invested until you know what's really going on.
I have seen a picture of a national champion rifle shooter in the mid 1930s whose barrel was wrapped end to end with solder. He couldn't get a heavy barrel rifle so worked out his own !!! He was a long-deceased member of my gun club.
I did some pellet tests a few years ago at 17yds in .177 and was surprised how much the groups moved around on the target depending on weight. As you noted gravity shouldn't have that much impact at such a short range. I found that the very heaviest pellets weren't tolerated by my rifle and gave much lower velocities that I anticipated. As others have said, 21gr is pretty heavy for a springer - even a magnum like the 350.
-
Thanks for all that great info and suggestions guys.
Hector, what I want to achieve is long-range shots which is why I'm excited about the heavy grains. I'd prefer to tweak the gun to be more pellet friendly if I can rather than have to order specific pellets online. I live in the rural deep south.
What do you think about sleeving the barrel with a 2mm thick carbon fiber tube? 20mm OD X 16mm ID.
The pellet goes in deep enough, I don't think it touches the chamber end at all when closed.
I try to push them as far as I can to avoid deformation
Here is the after picture.
Can you send me the link to the muzzle weight you recommend?
-
Here is the before pic just for reference.
-
For comparison, this is the H&N FTT in 5.53, again the barracuda is 5.50. I think this shows the mark from the breech closing and this one shoots exactly where I put it. The 5.50 fits like butter (doesn't fall in but also not tight AT ALL) and the 5.53 FTT clicks in at first then goes in smoothly.
-
I tapped 3 pellets with a nail up the skirt hole to widen the head size a little for a tighter fit.
Still, all landed 5" below :( so it's not the snugness of the fit. Definitely barrel harmonics.
Would've been nice if the randomness of the throw was too high not too low.
-
Here is the test with some makeshift weights I taped on. It straightened the shot half of the distance. Interesting!
-
David,
What you are seeing makes me wonder how tight ball detent locks the breech on your 350. I am contemplating the idea that the barrel is able to pivot downward slightly during the firing cycle, due to the ball detent not being as positive as it should be:
It is clear from the bright witness marks that your breech closes all the way, metal to metal. The question is if it stays there during the firing cycle...
If you pull the barrel down slowly, is there obvious movement at the breech before the detent "pops"? While lubricating the ball might seem like the wrong thing to do, it may also remove friction in its channel, that just might be preventing the ball from travelling all the way out for the most ridgid lockup possible.
If you slam the breech shut a little too hard, it may be bouncing slightly open then staying that way because of ball friction in its channel. Yes, a sticky detent should also be present when shooting lighter pellets. However, the timing of the breech block bounce and the angle of the barrel at pellet exit may be different.
Should you lube the ball with oil or grease, be careful to keep that away from the breech seal area, as air heated by compression will tend to ignite any oil exposed to the hot air stream - further confusing the issue and possibly causing other trouble.
Experiment with closing the breech more softly. Just hard enough to hear s light metal to metal sound.
If you are the second owner of this rifle; also try closing the breech slightly more firmly. This, while maintaining upward pressure on the barrel slightly longer than would seem required to close the breech.
-
Here is the test with some makeshift weights I taped on. It straightened the shot half of the distance. Interesting!
That is a signal!
-
The closing mechanism is very defined and tight like a swiss knife, it always stops at the exact point.
When it's cocked and broken, the barrel part is nice and tight, doesn't swing down with gravity when it's cocked.
-
That is good to know, David
This suggests the barrel is flexing over half a degree, based on the scale construction image captured below. Perhaps that is not unusual for such a potent springer.
All dimensions in inches and degrees. 504 " = 14 yards
-
Excellent, thanks for that.
I'll go ahead and order the tube and start with the easiest possible and most good looking ;D fix.
-
To avoid disappointment, call it an experiment. You could end up with it shooting 5" high :)
For CF tube to reduce barrel flex, the tube would need to be bonded to the barrel. That seems aggressive to me. A tight slip fit might make a smaller, but possibly useful difference. You will only know if you try it.
-
To avoid disappointment, call it an experiment. You could end up with it shooting 5" high :)
For CF tube to reduce barrel flex, the tube would need to be bonded to the barrel. That seems aggressive to me. A tight slip fit might make a smaller, but possibly useful difference. You will only know if you try it.
Oh, I wish it would go 5" high, then I can tighten the sight instead of cranking it open.
I just finished shooting with different weights/metal objects attached, nothing changed, still closer than without weights and I did take them off to recheck and yes the shots went further down without any weights.
I will definitely try it without epoxy first, what about red Loctite is it permanent?
If the tube brought the shots a little up like the weights ill be happy.
-
Some of the carbon fiber tube thread links I posted above discuss pros and cons of different adhesives.
Loctite has thread lockers, gap fillers and adhesives. I am not an expert, so some research is indicated. Generally, some Locite products are considered more permanents, and require higher temperatures to release.
https://www.henkel-adhesives.com/nz/en/insights/all-insights/blog/difference-between-threadlockers.html (https://www.henkel-adhesives.com/nz/en/insights/all-insights/blog/difference-between-threadlockers.html)
https://www.henkel-adhesives.com/us/en/products/industrial-adhesives/retaining-compounds.html (https://www.henkel-adhesives.com/us/en/products/industrial-adhesives/retaining-compounds.html)
Solvents, such as acetone will often dissolve Locitite. That said, the "wetted" front where the solvent could contact the adhesive between barrel and sleeve is tiny. So, you might need to submerge the whole barrel in a closed tank, for rather a long time.
So; because a CF tube will have such a large bond area to the barrel, I would consider the CF tube permanent. Unless you don't mind scorching the tube with a torch. You could then probably clean off the residue with acetone. I could be wrong about this
If you contact the people who made the CF tubing tensioned barrel airguns in the above threads, I am sure they can give you advice, including about reversing the application. If you feel odd about asking them via private message, then start a thread on the topic; or post it to this thread. Either way, I have no problem asking people for input via PM, on threads that are not my own. I accept that some will decline...
-
I think if the muzzle weight you attached is more securely and rigidly fastened, it might have more effect. Something more like two hose clamps, than a slightly loose Sellotape wrap.
-
Before you go the the barrel tube route, try adding a muzzle weight/break to the barrel. That in and of itself should help.
Something like this:
https://www.airrifleheadquarters.com/page/page/1205004.htm (https://www.airrifleheadquarters.com/page/page/1205004.htm) ;)
-Y
-
(https://www.airrifleheadquarters.com/i//mods34532.jpg)
The aluminum barrel weights Yogi suggested above are elegant, but rather limited for varying the weight, or moving weight around to change the barrel harmonics. Also, you may have to file on the barrel to get them on:
Rather than filing on the barrel to remove the raised metal where the front sight mount is swagged into the barrel, how about the split collars below? You can use more than one in a stack, if one is not enough. There are also longer versions of these clamps.
The clamps are easily moved, or removed. There is no grubscrew mark left on the barrel, should you move or remove the "weight":
Select the barrel diameter from the menu on the left: https://www.mcmaster.com/bushings/shaft-collars-and-couplings/two-piece-shaft-collars/system-of-measurement~metric/ (https://www.mcmaster.com/bushings/shaft-collars-and-couplings/two-piece-shaft-collars/system-of-measurement~metric/)
Assuming a 16 mm barrel diameter (?) https://www.mcmaster.com/6063K17/ (https://www.mcmaster.com/6063K17/)
(https://www.mcmaster.com/mvA/Contents/gfx/ImageCache/606/6063K17p1-d03c-digitall@2x_637018026611702064.png?ver=ImageNotFound)
https://www.mcmaster.com/9746T2/ (https://www.mcmaster.com/9746T2/)
(https://www.mcmaster.com/mvA/Contents/gfx/ImageCache/974/9746t1c1-1562074343-p9@2x_636976531455316382.png?ver=ImageNotFound)
You can get them cheaper from amazon: https://www.amazon.com/s?k=Clamping+Two-Piece+Shaft+Collar&ref=nb_sb_noss_2 (https://www.amazon.com/s?k=Clamping+Two-Piece+Shaft+Collar&ref=nb_sb_noss_2)
Which is the best source in NZ is for you to figure out.
-
I like the idea of sleeving the barrel to make the barrel thicker to aid in the cocking grip. I ordered a 20mm OD/16mm ID. Do you think I should get split collars in a diameter that will fit over the sleeve, or put sleeving to the side and try the weights alone first?
-
You may need to get two sizes of collars. One with a 20 mm ID. The other for a 16 mm ID.
Of course you could wind a short section of tape tightly around the barrel and just attach the 20 mm ID collar without the sleeve.
Trying different combinations of weight; weight and sleeve; and sleeve only should provide useful info.
My prediction is that until you bond the sleeve to the barrel, that the weight will provide the strongest signal. Moving the weight an inch up or down from the muzzle should make a noticeable difference on target. If it seems to make no difference, move it half an inch back. You will find several vibration "nodes" where the effect comes and goes.
-
Thanks for all that great info and suggestions guys.
Hector, what I want to achieve is long-range shots which is why I'm excited about the heavy grains. I'd prefer to tweak the gun to be more pellet friendly if I can rather than have to order specific pellets online. I live in the rural deep south.
What do you think about sleeving the barrel with a 2mm thick carbon fiber tube? 20mm OD X 16mm ID.
The pellet goes in deep enough, I don't think it touches the chamber end at all when closed.
I try to push them as far as I can to avoid deformation
Here is the after picture.
Can you send me the link to the muzzle weight you recommend?
David;
The farthest south we reached was Queenstown, from there we flew back. You can read a little about our experiences in Aotearoa here:
https://www.ctcustomairguns.com/hectors-airgun-blog/veronika-and-hector-down-under (https://www.ctcustomairguns.com/hectors-airgun-blog/veronika-and-hector-down-under)
We had a lot of fun and will always remember fondly the Kiwis (the people, not the birds). ;-)
IF you are interested in long range shots, then the use of Iron sights seems somewhat conflicting, unless you are planning in the future to use some sort of "Ladder" / Tang sight, like the Credmoors of old.
(https://imagizer.imageshack.com/v2/800x600q90/923/XbsMoG.jpg)
I have, and they are a ton of fun. IF that was the case, then the low shooting of your gun is really no problem, the bad accuracy is.
From your pictures, I would suggest you get some 5.52 and 5.53 head size Baracuda Match. Whoever is importing the H&N line should be able to get you a tin of each. And try those.The improvement of the shot consistency between the "nail tapped" and the "untapped" pellets tell me that you have a "largeish" bore and the 5.50 headed Baracudas are not achieving their full potential.
One thing about wrapping things around barrels is that they need to fit TIGHT. Otherwise, you are introducing one more degree of freedom into the system and that will create REALLY CHAOTIC vibrations.
Every single barrel I have CF sleeved has been permanently glued, tensioned barrels are not as interesting in airguns as they are in PB's because the reduction of the bore through the extremely high tensions used is not conducive to accuracy in airguns and we used choked barrels. So, I would not suggest you think of tensioned barrels.
CF sleeving is not complicated, but it does work better when there is NO SPACE between sleeve and barrel. You can use Loc Tite 680 to attach one thing to the other, though I use JB weld when the CF sleeve leaves little space to be filled, OR even casting resin (what is used to make fiberglass) when the space desired is large.
(https://imagizer.imageshack.com/v2/800x600q90/922/vbhgty.jpg)
(https://imagizer.imageshack.com/v2/800x600q90/924/XheKvv.jpg)
In GENERAL, for springers, I prefer to use the CF sleeve to create a Reflex device:
(https://imagizer.imageshack.com/v2/800x600q90/922/3YA8yo.jpg)
The same device offers harmonics tuning capabilities.
You do not need a lot of weight. Just 30 grams moved mm by mm will show in a target at 20 meters.
I would use Peter's suggestion of the split collars, and see where that takes you, again, mm by mm; plus different pellets.
Last thing you need to know is that ALL breakbarrels are sensitive to the way the bedding is achieved, and the bedding is, in part, dictated by the torque in the screws.
So, get a torque wrench and tighten the two forend screws to about 20 in-lbs.
Then tighten the rear stock screw to 30 in-lbs and "unscrew" that screw by half turns, you should readily see a change in the grouping till you reach the best point possible (DO NOT pay attention to the POI), then retighten and undo by 1/4 turns, then retighten and undo by 1/8 of a turn till you are satisfied that you found the optimum for your rifle.
Once you have done that, then worry about the POI.
;-)
Kia Ora Haere Ra!
HM
-
I like the idea of sleeving the barrel to make the barrel thicker to aid in the cocking grip. I ordered a 20mm OD/16mm ID. Do you think I should get split collars in a diameter that will fit over the sleeve, or put sleeving to the side and try the weights alone first?
David 110,
My understanding is that the weave of the carbon fiber tube is extremely important to effect the barrel harmonics. If the weave is not right you might make it worse. ;)
-Y
-
Hector,
Beautiful photos, it looks like you had an amazing time here and a successful competition. Isn't it a beautiful country, I feel like I live inside a calendar 😂 It's funny that I came from the flattest spot, Chicago. This is my 3rd year living here in Dunedin, not far from Queenstown.
All the toys look amazing but I had another look and no gun-related accessories can be brought into New Zealand without police permission and/or a gun license.
While I'm waiting for the CF tube and the clamps Peter suggested, I decided to make sure everything is working and clean from the inside out. I took out the piston seal very slowly and carefully so as not to damage it as the gun has yet to be deburred and I wanted to get the seal out in it's factory condition. It does seem to have a small nick on it.
(https://imagizer.imageshack.com/v2/xq90/922/oMLuBm.jpg)
(https://imagizer.imageshack.com/v2/xq90/922/Libwhn.jpg)
(https://imagizer.imageshack.com/v2/xq90/924/zMCla9.jpg)
(https://imagizer.imageshack.com/v2/xq90/923/t43EHf.jpg)
I know it won't cause the drop issue we've been discussing, but will this have any effect on the timing of the pellet leaving the barrel with a heavy grain?
-
That seal appears "shaved" at the lip. If it had been split, I think it would have much greater potential for leaking. That said, any obvious damage to a new piston seal seems unnecessary and disappointing.
It is possible that the seal is leaking enough air that the piston crashes into the front of the compression cylinder harder than usual, on firing. This crash could have more effect with heavier pellets because they take longer to leave the barrel.
That could mean that you are seeing more barrel vibration and a slight loss of velocity due to the seal leakage. With heavy pellets, those factors might very well account for the point of impact shift you were seeing. I think it plausible that your original trouble will go away after you replace the seal...
-
Yeah, I'll definitely be changing the seal and testing it with this same tin of barracudas before anything else, just to know.
-
We seem to continually forget the pressures that are reached inside a piston/compression chamber arrangement.
People! we're creating peak microsecond pressures in excess of 4,000 PSI's. Even across a millisecond time average, pressures exceed 800 PSI.
That nick in the lip gets flattened out completely during those times.
Parachute seals seal the LEAST under LOW pressures, that is why the "Blow with all your lungs into the barrel" test is so telling, it is the worst possible condition for the seals to do their job.
Yes it is disappointing to see a rifle assembled hastily and without the care WE put into our airguns, but production workers are what they are and as long as the rifle meets the specs, it leaves the plant.
In this particular instance, we want the rifle to perform with a pellet that is not quite within the "normal" realm for spring-piston guns. So, it's not like this should have popped during registration firing (power level documentation for legal purposes), as in that case, the most efficient pellet for the powerplant is used so as to keep to legal limits.
By all means, de-burr and polish the slots, it never hurts, but more important than that, get a strip of measuring tape, anneal one end and create a lip, then you can insert it between piston and mechanisms tube and cover the slots while you are pushing everything in.
Once the seal is past the last round hole where the cocking arm engages with the piston, you can remove the strip and finish the assembly. This will protect the seal as it is going in.
Lastly, you CAN "regulate" the barrel so that it shoots to where you want it to shoot. IF you are really set into what you are doing, that is the best option. BUT, I will insist: YOU NEED TO TRY DIFFERENT HEAD SIZES. You need to find accuracy before you want to attain precision.
I can almost grasp your liking of NZ. As a "flatlander" the Southern Alps must be simply amazing. Hope your stay will be happy and healthy and that you find a bright future there.
You'll never stop being a "Chicago boy", but that does not mean you cannot become a proud New Zealander as well.
NZ is a country that reminds me strongly of the USA in the 60's. And there is nothing wrong with that.
;-)
Keep well and shoot straight!
HM
-
Thanks Hector for pronouncing that seal OK.
That said, you know that I can't resist a good argument:
While that seal may conform to the cylinder just fine at 4000 PSI; when the piston is half-way through its stroke, the pressure is around 15 PSI (maybe a little more due to adiabatic heating). If the seal might leak at "low pressure", how much air volume might leak by the seal, before the air pressure reaches a few hundred PSI?
I think an easy way to answer the above would be by shooting benchmark pellets. If they they reach velocities, with FPE that is within 5% of nominal of those with a "virgin" seal, then my argument is purely theoretical. Else, it may be part of the problem seen with heavy pellets. Even a stronger indicator, would be to compare FPE with heavy pellets; when using a virgin seal compared to this particular damaged one.
-
David, I think you are complicating things. By now, I would forget about harmonics, and restart from the very basics.
No matter where are the POI, at 15 yards, you need much better groups.
Adjust the trigger to be light, find the holding and resting to achieve much tighter groups. To think about long distance demands that you are being excelent at short distance.
At 15 yards, with the HN FTT 5.53, the groups should be ok. Or, you may try the JSB, 15.89 and 18.1 gr. If you can't achieve very good groups, the barrel is not the culprit. Considering holding, resting and squeezing the trigger, the shooter is doing something wrong.
Just to let you know, for my D 350, the HN FTT 5.53 is the more consistent one. Trying heavier pellets, the Baracuda 5.53 was too tight; the 5.51 fitted ok, but I couldn't have good groups. The JSB 18.1 5.52 is being much better.
If you have access to a chrony, to check the consistency of fps is very important.
-
David, I've been reading this thread & it seems possible that while harmonics may be at play, it may also be shot timing( position of barrel @ time pellet leaves the barrel.The heavier ' Cuda, taking longer to " pop the leade, in relation recoil cycle.
For a good long range pellet( as others have said, try a JSB/ AADF 15.9 grain. Try these out to 30 - 35 yards. At that point , yardage - wise you can seperate the wheat / chaff for a "distance" pellet. Also , pay no heed to head size labeling( rarely accurate) go by a die & batch #
Happy shooting.
See if you can get a JSB sample pack from Gunworks Ltd. NZ.
-
Hector, I ordered a new seal, but after reading your comment I decided to give this seal a chance while I wait for the new one to arrive.
I also went and got a tin of barracuda match which has a bigger head size (5.51) fits nice and tight, same results ( 5-4" below aim point).
I did deburr everything and used your sliding method of reinstalling the seal. It even cocks smoother now.
Next, I'll try the CF sleeving with JB Weld, then the last resort will be the split collars.
Christopher, thanks for the Gunworks suggestion, I'll try that.
-
Thanks Hector for pronouncing that seal OK.
That said, you know that I can't resist a good argument:
While that seal may conform to the cylinder just fine at 4000 PSI; when the piston is half-way through its stroke, the pressure is around 15 PSI (maybe a little more due to adiabatic heating). If the seal might leak at "low pressure", how much air volume might leak by the seal, before the air pressure reaches a few hundred PSI?
I think an easy way to answer the above would be by shooting benchmark pellets. If they they reach velocities, with FPE that is within 5% of nominal of those with a "virgin" seal, then my argument is purely theoretical. Else, it may be part of the problem seen with heavy pellets. Even a stronger indicator, would be to compare FPE with heavy pellets; when using a virgin seal compared to this particular damaged one.
Peter;
What you suggest is more or less what is done in the "Fire for register" process.
A gun needs to yield specced power or it does not leave the plant. A seriously cut seal will NOT yield specced power.
Even a trained person can rarely exceed 15 PSI's on lung power alone (more like 10 or 11 PSI's), so, AGAIN, blowing into the barrel with all your lung power is the WORST test you can inflict on a parachute seal. If it seals with your lungs, it will seal within the first 1/4" of piston travel.
I agree with Marcos, and have been insisting that David takes care of the group size first.
I cannot agree with Chouchin because, as heavier pellets DO leave the barrel at a different point in the recoil cycle, they do leave the barrel when the muzzle is pointing "more upwards" than a iighter pellet, and at 14-15 yards, this is one of the typical quandaries. At longer ranges, yes, things get reversed. Unless David's bench technique is different from the rest of us and he lodges the heel of the stock in the crook of the shoulder, I cannot see a reason why the recoil would make the barrel point "more downwards" than under normal circumstances.
Though, in airguns, everything is possible . . .
Keep well and shoot straight!
HM
-
Hector,
What I usually do to check the seal is half cocking while blocking the air chamber port and feeling the pressure release. It does feel well sealed with that test.
Remembering that the original problem was the barracudas specifically shooting 5 whopping inches low. Also remembering my test of holding the gun horizontally "gangster style", the pellets in that test shot 5" to the right (shooting right-handed).
1, it's not the weight or power plant lacking, since it did not go down with gravity in the gangster test.
2, it's not shooter error. I'm shooting handheld standing or sitting (half kneeling) so groups will naturally be looser. Yes, I'm not the best shooter but you can see similar-sized grouping with all pellets whether 5" low like the barracudas or on aim like the rest. Perhaps I'll get a chair and table out to show you all cleaner grouping 😂
-
Hector,
What I usually do to check the seal is half cocking while blocking the air chamber port and feeling the pressure release. It does feel well sealed with that test.
Remembering that the original problem was the barracudas specifically shooting 5 whopping inches low. Also remembering my test of holding the gun horizontally "gangster style", the pellets in that test shot 5" to the right (shooting right-handed).
1, it's not the weight or power plant lacking, since it did not go down with gravity in the gangster test.
2, it's not shooter error. I'm shooting handheld standing or sitting (half kneeling) so groups will naturally be looser. Yes, I'm not the best shooter but you can see similar-sized grouping with all pellets whether 5" low like the barracudas or on aim like the rest. Perhaps I'll get a chair and table out to show you all cleaner grouping 😂
Now that you have explained further, I THINK I understand now.
I like the way you think, quite "unorthodoxically", LOL!
Given your "Gangsta" test, I would look into the breech seal again and make sure that I don't have a shim under the ORing.
The logic is that a bigger gap between barrel and breech face might give the high pressure spike a chance to "open" the breech a little.
The more time it can do so, the more difference there will be between a faster exiting pellet and a slower exiting pellet.
That "opening" would mean a downwards pointing barrel when held in the normal position and a right hand pointing barrel when held in the "gangsta" position.
It is also a possibility, in the world of airguns that take +45# of peak cocking force, that the barrel got bent downwards, and while the effect is not that noticeable with FTT's or JSB's in the medium weight range, it IS noticeable in the Baracudas.
One of the things that few people notice is that in 0.177" and 0.20" the difference between the FTT and the Baracudas is MUCH smaller than in the case of the 0.22"; for example: in the 0.177" the difference between 8.64 and 10.6 is less than 25%, but between 14.6 and 21.1, it is almost 50%.
When discussing with JSB their lineup, many years ago (2009), the decision was to create a 14.3 gr. 0.22" to allow those users of Premiers to have an alternative, and then the next step up was the 18 grs. offering as the "heavy" pellet. Now you have the Monsters and the Beasts, but those are definitely PCP territory. Same could be said for the 0.22" Baracudas.
Another thing to note is that, as far as long range shooting, the best pellets for that are the 16 grs. JSB's (Exacts Jumbo). They are in the sweet spot between power/velocity & stability.
Gunworks seems to have them at the best price, though AirRifle Co also seems to have them.
GunCity seems to stock only the RS's (too light for long range), and the Predators.
https://www.gunworks.co.nz/shop/item/22cal-air-rifle-pellets-jsb (https://www.gunworks.co.nz/shop/item/22cal-air-rifle-pellets-jsb)
The OTHER thing that might be affecting the POI in such a hard kicking airgun is your trigger hand hold. If you place your hand high on the pistol grip and with a tight hold, it COULD make the gun shoot low with slower pellets.
Try using the benchrest trigger pinch and see what happens.
Normally, for accuracy's sake, all airgunners learn to have a very loose holds. In 90% of the cases, this works. Not always. But it is worth testing.
In the end, David, if your gun is yielding comparable groups between quality pellets (and that is something that was not evident from the first set of pictures), then you can easily "regulate" the barrel to shoot where you want it.
Barrels are "regulated" at the factory with some reasonably standard pellet, and the Baracudas in the 0.22" cal. are not one of these.
Thanks for the additional information!
HM
-
Hector,
It's been raining here for days so I haven't had much opportunity for shooting. I checked all the things you mentioned and didn't find any shims or any evidence of problems with the barrel. It's still only the barracudas shooting south.
I'm now just waiting for the sleeve to arrive to see if that helps the barrel harmonics. I'm worried that the 16mm ID tube won't go past the front sight dovetail, which is 16.30mm at some points. If I do manage to get it on, will sleeving the barrel have a negative effect on the other kinds of pellets? I can't think of any way to test before making it a permanent change.
I read a long time ago somewhere that some magnums don't like a completely loose artillery hold. I tried your advice and let the gun float on my palm and the results were amazing. Still, barracudas shoot way south. Two people tried and the barracudas still shoot south. Should I just give up on the barracudas, get the 18gr JSB and move on with my life? 😂 It just guts me that it's a powerful magnum and didn't like the heavy pellets. It could be an H&N brand thing like you said.
The bottom is a 9 shot group using cheap gamo pro magnum penetration 15.42gr and a very loose hold.
(https://imageshack.com/i/pnJ3FPq5j)
-
Hector,
It's been raining here for days so I haven't had much opportunity for shooting. I checked all the things you mentioned and didn't find any shims or any evidence of problems with the barrel. It's still only the barracudas shooting south.
I'm now just waiting for the sleeve to arrive to see if that helps the barrel harmonics. I'm worried that the 16mm ID tube won't go past the front sight dovetail, which is 16.30mm at some points. If I do manage to get it on, will sleeving the barrel have a negative effect on the other kinds of pellets? I can't think of any way to test before making it a permanent change.
I read a long time ago somewhere that some magnums don't like a completely loose artillery hold. I tried your advice and let the gun float on my palm and the results were amazing. Still, barracudas shoot way south. Two people tried and the barracudas still shoot south. Should I just give up on the barracudas, get the 18gr JSB and move on with my life? 😂 It just guts me that it's a powerful magnum and didn't like the heavy pellets. It could be an H&N brand thing like you said.
The bottom is a 9 shot group using cheap gamo pro magnum penetration 15.42gr and a very loose hold.
(https://imageshack.com/i/pnJ3FPq5j)
Yes, it DOES RAIN n Aotearoa! LOL.
As you have seen the loose hold does improve the groups, now if you really want to make your gun shoot to POA, then regulate the barrel! It's not a PB that holds tens of thousands of PSI away from your face. Just regulate the barrel and shoot whatever pellet you want that shoots well.
Really, there is nothing magic about an airgun barrel's orientation.
Good luck and keep us posted!
HM
-
When you say "regulate the barrel" do you mean the sleeving and weights?
-
When you say "regulate the barrel" do you mean the sleeving and weights?
Nope!
I mean "bending" the barrel in an extremely controlled manner at the proper place to obtain the most stable POI at the right spot where you want it because, IIUC, all this comes from the usage of the iron sights that have a limited travel. ¿no?
Though you COULD try a simple "riser plate" underneath the OEM iron sights . . . ;-)
¿no?
HM
-
Ya those holds are a funny thing. My new spring D350 didnt like fingers wrapped around the stock. But didn't like an open palm either. At a loss, I did the open palm again but applied my thumb and index finger only. Magic ! And repeatable. Go figure.
-
What about shortening the front sight post? That removable front sight element seems like a cheap part to risk, and very little effort to shorten; or replace.
You only need to lower the front post by 1 mm to get those heavy pellets to target center at 14 yards. You could take off 1.5 to 2 mm to re-enable rear sight travel.
You might also consider a lower front sight base that fits the barrel dovetail. Perhaps one from Weighrauch.
A spacer plate on the rear sight would achieve the same thing, but is more work to make than a shorter front sight. Depending on the rear sight screw lengths, you might be able to just put in 1 mm thick washers. 2 mm longer screws should not be too hard to find. Then use 2 mm thick washers or two 1 mm washers...
-
If you see my second post on the 1st page I posted a picture of the whole rifle, you can see the iron sight sitting on a bunch of washers. It does help but cosmetically it looks and feels like a bandaid. I ordered longer hex 10.9 grade steel screws to get a deeper bite and I'm trying to find an appropriate aluminium plate as suggested.
Shaving the front sight post will mess with the half-circle view and will need more than half of the needle to be trimmed. I had thought of that but decided against it for this reason.
CF sleeve and weights are still on the menu, just waiting for them to arrive from China. I'm interested to see what effect they have.
-
David,
So, is the low grouping even with the washers installed; or was that an early experiment?
The barrel weight and sleeve will probably shift the group. They may also make groups tighter or wider. Mass damper tuning is usually used to tighten groups, rather than primarily to shift the central point of impact.
Anyway, trying a few option can only provide more information.
Bending the barrel sounds horrific, but there are a few threads on this forum about how to do it. The amount of bending would be about 1 mm down between front and rear sights. This assumes they are 19 inches apart, based on the 19.5" barrel length spec here: https://www.pyramydair.com/product/diana-350-n-tec-magnum-premium-air-rifle?m=4171 (https://www.pyramydair.com/product/diana-350-n-tec-magnum-premium-air-rifle?m=4171)
If the distance between front and rear sighting planes is actually 18.75", then the degree of shift or bend will be proportionally less.
Barrel bending would focus the bend near the breechblock, because it will shift the front sight the most there. Also, it is a natural point for the barrel to yield, due to the stiffness of the breech block. Of course, this depends on the technique used. The threads below show a few variations.
Posts about barrel bending - a bunch of selected links below the quoted post:
My new-2-me vintage Beeman C1 is shooting low....5" low at 10M with no hold-over.
It has a new Kruger 3-9X32 AO scope, I thought maybe it was defective so I swapped it with a Beeman 4x32 that has been fine on other rifles. Same deal.
Soooo, I swapped back the Kruger and put a .003 shim sandwiched with another layer of friction tape in the bottom of the rear ring. Now 4" and out of adjustment.
Standing back, looking at the barrel, I thought it had the dreaded Barrel Droop.
I took a straight edge and laid it on the barrel, turned it over and flipped it end for end... Yep, barrel is bent. :(
(In the pic I have a ruler to show the distance, but I used a true straight edge.)
Problem is, the bend is close to the pivot block, about 1-3/4" away.
If it were the whole length of the barrel I would just support each end on wood blocks and smack it with my deadblow BFH in the middle.
But being this close to the pivot block I will need to make a support and press some how. I know barrels can get bent "up" here from pulling the trigger when open and slamming shut, but mine droops down. I suspect from years (decades) of breaking it open. The barrel length on this C1 carbine is only 10-3/8" but it has a very FIRM lock-up, so you really have to palm smack it to breaking open.
Also, the cocking linkage is pinned to the block, not screwed or bolted so while I can remove the stock, I would like to do it with the action assembled.
- What have you used in such a case?
- How do you know how far to go?
- I assume baby steps, test firing each time but am worried about stressing the steel barrel making it weaker to bend again, or am I being paranoid?
- I am sure there will be some spring back so thinking it would need to go "over-center" in the jig?
I have an assortment of work benches, wood blocks, vices, C-clamps, Beam clamps even a Pipe clamp, so anything home made I can probably fab up.
I have "searched" the topic and nced did something like I am thinking except mine would need to be off set, not centered. (thanks Ed)https://www.gatewaytoairguns.org/GTA/index.php?topic=68011.msg155778015#msg155778015 (https://www.gatewaytoairguns.org/GTA/index.php?topic=68011.msg155778015#msg155778015)
If you made it this far, thanks for your consideration and let me hear your methods other than "putting it in the fork of a tree and pulling". :o
LOL!
I've been bending my HW airgun barrels for years so the poi is within 1" or so at 30 yards after optically centering the scopes and fine adjustments are done with the turrets. Here is the construction lumber, steel eye bolt, Delrin shoe, flat washer and nut contraption I've been using for a few years now...........
(https://i.imgur.com/rsK0loXl.jpg)(https://i.imgur.com/nppgPMCl.jpg)(https://i.imgur.com/hCUutJRl.jpg)(https://i.imgur.com/9M6gXwNl.jpg)(https://i.imgur.com/mfVQ9Q4l.jpg)(https://i.imgur.com/a3A9W5al.jpg)
I always place the end of the "barrel tweaker" against the barrel pivot block so no bending force is transferred to the pressed in barrel/pivot block joint. Also, if the barrel is bent too far it's easy to bend the barrel in the opposite direction since the "pressure point" is always at the same place along the length of the barrel. Here is the bending sequence I used with the new HW95 barrel I bought on sale from that Canadian retailer when they stopped selling hW parts a few years ago.........
(https://i.imgur.com/yXJd6eCl.jpg)
There are times when it's a bit more tedious to "put the poi where wanted" but with patience it has always worked. Matter of fact, a bend in an airgun barrel that moves the poi 4" at only 18 yards can't be seen with the naked eye!
Barrel bending threads:
https://www.gatewaytoairguns.org/GTA/index.php?topic=49873.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=49873.0)
https://www.gatewaytoairguns.org/GTA/index.php?topic=168557.msg155892495#msg155892495 (https://www.gatewaytoairguns.org/GTA/index.php?topic=168557.msg155892495#msg155892495)
https://www.gatewaytoairguns.org/GTA/index.php?topic=95539.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=95539.0)
https://www.gatewaytoairguns.org/GTA/index.php?topic=156328.msg155728487#msg155728487 (https://www.gatewaytoairguns.org/GTA/index.php?topic=156328.msg155728487#msg155728487)
https://www.gatewaytoairguns.org/GTA/index.php?topic=170803.msg155942963#msg155942963 (https://www.gatewaytoairguns.org/GTA/index.php?topic=170803.msg155942963#msg155942963)
-
I bent it today but was too late to fully test it.
The elevation is tightened all the way down with the normal 15ish grain pellets, 'cudas are still 5" below so it will need about 12 clicks to compensate.
I'll shoot more tomorrow and post the results.
-
Jolly good, Dave
It would be interesting to see a picture of the barrel out of your bending fixture. Thanks
-
Jolly good, Dave
It would be interesting to see a picture of the barrel out of your bending fixture. Thanks
Doesn't really look bent 8)
-
Thanks David,
Not looking bent is exactly what you want. It needs to be subtle; not obvious. And besides, the adjustment you want is just slightly more than one millimetre...
-
As the Brits would say:
"Jolly god show, old man!"
;-)
HM
-
Top left is 10 shots of FTT, then I sighted to the barracudas with the other targets. The 10 shots bottom left are the final results. All @ 13-14 yards.
What's bizarre is the difference between the two kinds of pellets is 26 clicks (!) of elevation on the iron sight. That shot below the top right target was the first shot after switching from FTT to barracudas, landed like 4-5" below.
I wonder if a stiffer barrel (sleeved) could minimize this gap. Now normal grain pellets shoot straight with elevation tight all the way down, so any more barrel bending will make most pellets useless in this gun.
Wanted to thank you all, especially Hector and Peter, for the wealth of info, help, and encouragement.
-
It works!
Are you going to post your sleeve / weight results to this thread, David?
-
It works!
Are you going to post your sleeve / weight results to this thread, David?
You know I won't let this settle until I've tried everything 😂
The sleeve and weights seem like they'll take a while to arrive from China but I will come here to update once they arrive.
I measured the flares of the front dovetail and they are 16.3mm, the internal diameter of the sleeve I bought is 16mm. I've never dealt with carbon fiber so I don't know how much give it has, I wonder if I'll be able to tap it past the dovetail or if the .3mm won't be a problem or if I won't be able to use it at all.
I want to try the 18gr JSB's as well and see if they'll act like the normal grain pellets without a dramatic drop, or if they'll land halfway between the normal and the barracuda. If they land halfway, I'll bend it more and make this gun 18+gr since it's a magnum.
-
It is highly likely that the CF tube will go over the small front site dovetail with light tapping. It does depend on the wall thickness and weave of the CF. However, the total increase in circumference at the dovetail is not very large, nor is it very long.
Be careful about not breathing in CF dust from the tube end cuts, or getting it in your eyes. Before and after, a light wipe down with paper towel should take care of most loose bits.
-
David,
On top of what Peter says, do understand that loose things create inaccuracy.
If you get shotgun patterns from the loose tube do not be disheartened. SOMETIMES just making sure that the tube fits real snugly at the REAR and at the FRONT is enough for a test. If you see a dramatic change, you can then decide to make the whole thing permanent.
Keep well, shoot straight and keep us posted!
HM
-
It is highly likely that the CF tube will go over the small front site dovetail with light tapping. It does depend on the wall thickness and weave of the CF. However, the total increase in circumference at the dovetail is not very large, nor is it very long.
Be careful about not breathing in CF dust from the tube end cuts, or getting it in your eyes. Before and after, a light wipe down with paper towel should take care of most loose bits.
I'll be using a dremel, wearing a mask and eye protection, and I'll choose a very windy day to work outside. It's a 2mm thick tube 20x16 https://www.aliexpress.com/item/32800195932.html?spm=a2g0s.9042311.0.0.21a74c4djM93o3 (https://www.aliexpress.com/item/32800195932.html?spm=a2g0s.9042311.0.0.21a74c4djM93o3)
Hector, I'm all in on the sleeve. As long as there isn't a chance it will mess up precision when it's secured tightly (?), I'm willing to JB Weld it completely from the first installation.
-
First of all, I would certainly try the JSB 18.1.
FYI, with my scoped D 350, I zero with the HN FTT 14.6 at 20m, and the JSB 18.1, besides grouping well, hits pratically at the same POI. Don't ask me why, just a mystery I can live with.
.............
Btw, a chrony is always a must to act as a probe to the inside parts health.
For instance .. https://www.gatewaytoairguns.org/GTA/index.php?topic=151661.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=151661.0)
Hector already said it, and so well.. an airgunner without a chrony is like a doctor without the stetoscope.
..............
Speaking of doctors, it seems to me you are deciding to put a prosthesis without testing enough the patient.
-
First of all, I would certainly try the JSB 18.1.
FYI, with my scoped D 350, I zero with the HN FTT 14.6 at 20m, and the JSB 18.1, besides grouping well, hits pratically at the same POI. Don't ask me why, just a mystery I can live with.
.............
Btw, a chrony is always a must to act as a probe to the inside parts health.
For instance .. https://www.gatewaytoairguns.org/GTA/index.php?topic=151661.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=151661.0)
Hector already said it, and so well.. an airgunner without a chrony is like a doctor without the stetoscope.
..............
Speaking of doctors, it seems to me you are deciding to put a prosthesis without testing enough the patient.
Yea, he is amputating sprained ankle. I bet it shoots worse, much worse... ??? :-\
-Y
-
First of all, I would certainly try the JSB 18.1.
FYI, with my scoped D 350, I zero with the HN FTT 14.6 at 20m, and the JSB 18.1, besides grouping well, hits pratically at the same POI. Don't ask me why, just a mystery I can live with.
Have you tried your 350 with the barracudas after sighting with the FTT's?
-
Carbon fiber is very brittle, like glass it has nearly zero elasticity. I would expect it to split going over the sleeve
what you are talking about is a permanent fix, can not be undone and not even sure of the out come. think hard before you take that step
For a long range gun the most important consideration is accuracy, that would mean that at your 14 yard range you should be shooting one hole raged groups with your open sights.
second is a flat trajectory, the heavy pellets will have a rainbow trajectory and range estimation will be extremely critical,
Worry about POI after you get the accuracy dialed in.
I have the referenced chronograph and it works well for comparing different pellets and consistency of velocity at under $30.00 it is cheep. You will know if your gun is with in spec
At this point I would recommend working on accuracy, and finding a pellet and hold that your gun likes,
Last you did not say what long range was, but I think most would consider it to be out side of 50 yds.
Dennis
-
Hector, I'm all in on the sleeve. As long as there isn't a chance it will mess up precision when it's secured tightly (?), I'm willing to JB Weld it completely from the first installation.
No need for a first-permanent "installation".
Get some Teflon tape, the one that is used in plumbing. Then wrap some turns at the rear and some turns at the front.
Make sure you get a REALLY SNUG fit "screwing" the CF tube into the barrel.
DO check that the OD of the CF does NOT PREVENT A FULL COCKING STROKE!
If it does, then the "rear" of the sleeve should be where the CF needs to stop to allow you to cock the gun.
ONCE you have done this test, if it does not provide a dramatic change, then gluing the CF will not create it.
I repeat, the tape is to allow BOTH front and rear of CF tube to be fully supported and not wobble. FIT HAS TO BE TIGHT!.
HTH, keep us posted!
HM
-
A long answer to a simple question..
David, a major landmark from my learning curve with the D 350 is to be so careful about not jumping to conclusions. The thing is to pursue consistency of the whole team - shooter, rifle, aiming device and ammo. The results come from an interaction of the players, and each one may be a cause to inconsistency.
When inconsistency occurs, you have to go step by step, carefully analyzing each player. In my case, the shooter is always the first suspect. Once checking the stock screws.., only when I am convinced about doing well my part, as a next step, I will check the rifle with a chrony, the aiming device, ..
Btw, when shooting open sights, the rear sight of my D 350 has a horizontal play. So, before each shot I have to remember to push it to the side with my thumb.
All that said, I tried the Baracuda Match in 2017. I had some good groups, but, the consistency didn't last, and I gave up. Considering the other possible causes, I can’t have a ‘definitive’ conclusion about them not behaving good with this rifle. They were just not working at the time and I stopped using them.
At that time, at 20m, and no matter group sizes, the POIs of Baracuda Match were all about "3" inches lower than the FTT.
…………………………
I will insist. No matter if higher or lower are your groups, you are not having good ones. You have to find the right way to hold, rest and squeeze the trigger (adjusted to be light), and practice to be repeatable about each detail. At “14” yards, and to start the shooter challenge, you have to be able to achieve 1” groups, and consistently. Believe me, doing this you will learn a lot about your skills and your rifle.
Sincerely! Do not modify the barrel until you are more experienced with the rifle and pellets. It will just confuse your thinking about the basics.
-
No need for a first-permanent "installation".
Get some Teflon tape, the one that is used in plumbing. Then wrap some turns at the rear and some turns at the front.
Make sure you get a REALLY SNUG fit "screwing" the CF tube into the barrel.
DO check that the OD of the CF does NOT PREVENT A FULL COCKING STROKE!
If it does, then the "rear" of the sleeve should be where the CF needs to stop to allow you to cock the gun.
ONCE you have done this test, if it does not provide a dramatic change, then gluing the CF will not create it.
I repeat, the tape is to allow BOTH front and rear of CF tube to be fully supported and not wobble. FIT HAS TO BE TIGHT!.
HTH, keep us posted!
HM
The teflon tape is a BRILLIANT idea, I'll do that and keep you posted.
-
Did you consider the idea that I suggested as an experiment?
Wrap solder wire around about three inches of the barrel muzzle end and tape it in place to see if the harmonic stabilizer effect will help. Move it around on the barrel as shoot groups with different settings. Cheap and done in an afternoon! With.no damage to the rifle
Also as has been suggested several times, try different weight pellets. When I was testing pellets, I found one particular pellet of good reputation, that gave me a 7" 5 shot group at 20yds while the best groups were less that 0.4" under the same conditions.
Do the easy and cheap things first before any permanent or potentially damaging things first!
-
https://hardairmagazine.com/reviews/diana-panther-350-n-tec-air-rifle-test-review-22-cal/
this review of the 350 N-Tec 22 cal from several years ago. Best information is the table of pellets tested.
If you can find or have a ballistics program you might be able to determine whether the excessive drop is reasonable???
Dave
-
David,
It sounds like David110 is going to do what he is going to do. Does not matter what you tell him. :o
-Y
-
Did you consider the idea that I suggested as an experiment?
Wrap solder wire around about three inches of the barrel muzzle end and tape it in place to see if the harmonic stabilizer effect will help. Move it around on the barrel as shoot groups with different settings. Cheap and done in an afternoon! With.no damage to the rifle
Also as has been suggested several times, try different weight pellets. When I was testing pellets, I found one particular pellet of good reputation, that gave me a 7" 5 shot group at 20yds while the best groups were less that 0.4" under the same conditions.
Do the easy and cheap things first before any permanent or potentially damaging things first!
Sorry for the delayed reply, the new seal came in the mail so I've been changing and testing that.
If you see in my earlier post I did try taping some weights on to test as you suggested. It did cut down the distance of the drop a bit. I'm also waiting on pipe clamps as suggested by Peter, for a tighter fit. The soldering wire I have won't be enough to try your exact method but I'm looking forward to testing the pipe clamps in various places on the barrel. I don't think anything will bring the Barracudas up to normal grain pellets though. I'm not sure if you're following the whole thread but when I turn the rifle 90 degrees like a pistol the barracudas still land the same distance but to the right.
I also tried tightening the barrel hinge to stiffen it but that didn't change anything.
I have high hopes for the CF sleeve and the barrel weights that they'll fix the barrel with the barracudas. In the end, as everyone says, they simply may not be the pellets for my gun. I just enjoy solving problems ;D
-
Sorry about being repetitive. I must have missed that post. The result of the harmonic stabilizer should be to reduce group size rather than drop.
-
Sorry about being repetitive. I must have missed that post. The result of the harmonic stabilizer should be to reduce group size rather than drop.
You appear to have missed the underlined statement already made, also :)
-
All sleeved ;D Waiting for the JB weld to dry.
I did both of my guns, hoping to calm the barrel flip/kick on the hw95.
I'll update after testing soon.
-
You are teasing us, David :)
Results...
-
You are teasing us, David :)
Results...
It's 11 pm lol, if it wasn't the 350 i might ;D
-
You should have a sample of the glue that you mixed up to determine when it is set. Don't be tempted to stress the glue until a few hours after it is set...
You are the only one that can determine this. Don't jump the gun :)
-
You should have a sample of the glue that you mixed up to determine when it is set. Don't be tempted to stress the glue until a few hours after it is set...
You are the only one that can determine this. Don't jump the gun :)
Yes, let it sit overnight. Did you leave enough room to cock the gun?
-Y
-
The sleeve fixed the problem.
I shot 12 shots, 6 barracudas and 6 with FTT, the bottom right flyers from the 'cudas and the left from FTT. 15 yards. without any sight adjustments :D
I stripped the front sight and the front sight rails also look shaved too, it flew off twice. :(
-
So, David
The medium and heavy pellets that grouped 5" apart vertically now land at the same elevation? Jolly good then.
How much of that would you estimate is due to the sleeve, and how much due to bending the barrel?
-
So, David
The medium and heavy pellets that grouped 5" apart vertically now land at the same elevation? Jolly good then.
How much of that would you estimate is due to the sleeve, and how much due to bending the barrel?
Bending the barrel moved all pellets up, but the 5 to 6" gap between average grains and the 21 barracudas remained.
After fitting the sleeve the average weight pellets like FTT, went back down like I hadn't done the bend and the barracudas elevated up. It's like they met in the middle. This confirms that each grain/weight pellet makes the barrel dance differently.
I'm kinda bummed that it made the normal FTT pellets shoot lower like I didn't do the bending, the back sight was nice and tight with the bend. On the other hand, it's easier to cock, it looks good, and most importantly the barrel has to be stiffer and strighter after sleeving.
I'm waiting for some JSB 18 grains. to come in mail.
-
It's like they met in the middle
Sounds good to me.
-
Good Job!
Most of all it shows how much barrels shake when we release a pellet, LOL!
Keep well and shoot straight!
HM