GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: Dairyboy on September 11, 2018, 02:22:10 PM
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With all the new slugs coming out for airguns from NSA I've always wanted a .177 slug shooter. I have a .177 Mrod that has been sitting for over 6 months not even knowing how it shoots. Well put the .177 upper on the SS valved airtube I have from my .22. My goal is to have 2 tunes for it. 1 for slugs (hoping they shoot well!) and one for pellets to plink in the backyard and such.
5 shots shooting the 10.34 AA pellets at 22yds at a whopping 1100fps for a cool 27fpe! Lol can't wait to test slugs.
(https://image.ibb.co/fpNPS9/IMG_20180911_095254340.jpg)
Also 5 shots at 22yds around 900fps with same pellets. This is an accurate Mrod!
(https://image.ibb.co/iVFEup/IMG_20180911_095302276.jpg)
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Would love to see you stretch that distance out a bit with some larger shot count groups comparing the two velocities and see what happens. Might be very interesting.
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Yeah I'll do more once I get the slugs which should be Thurs. I just wanted to see quick accuracy and rough fps before I do any real testing. I always start at 22yds then move to 55yds once proven accurate at shorter distances.
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I certainly hope the slugs work well for you. I have some to try myself when time permits. But I am really interested in the comparison you've already put up using the AA pellets. I'd love to see that pellet compared with larger shot count group sizes at longer range between the two velocities you noted. Looks like you didn't lose any accuracy at increased velocity at 22 yards. Some 10 shot groups at 55 yards shot with the AA pellets at each velocity could be very informative.
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Subscribed!
Question: Are you using a stock choked barrel, or a modified one?
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Bone stock straight from crosman barrel. I have a buddy whose used a stock barrel and has awesome results with the NSA slugs.
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Good to know! Thanks for the info. Really interested to see how you do!
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Good to know! Thanks for the info. Really interested to see how you do!
Thanks! I'm excited to see as well!
I certainly hope the slugs work well for you. I have some to try myself when time permits. But I am really interested in the comparison you've already put up using the AA pellets. I'd love to see that pellet compared with larger shot count group sizes at longer range between the two velocities you noted. Looks like you didn't lose any accuracy at increased velocity at 22 yards. Some 10 shot groups at 55 yards shot with the AA pellets at each velocity could be very informative.
I'm curious as well so will be doing the test when I get the slugs and will do the comparison then. That way same shooting conditions and all.
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Will be watching and thanks for the effort. I'll post any results on NSA slugs through the Condor when I have a chance to shoot.
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subscribed ;D
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My Prod shoots the BBT's very well but it's far from being a stock gun too. That barrel seems to like them.
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My Prod shoots the BBT's very well but it's far from being a stock gun too. That barrel seems to like them.
my prod does well also with rick morrell's hpbt from the stock barrel,
but thats all thats stock too ;)
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Looking forward to your results, I have heard the .177 barrel is great for piledrivers.
Rocker1 did his magic to my Prod .177 bolt, .177 barrel, lead was worked on for ease of loading slugs & piledrivers port opened up and redid the crown, SS Valve ported to .160 and some LDC's.
It will be a while before I get to put it all together in my Prod.
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Can't wait to hear more about your .177 prod hammer Randy! I'll look into the piledrivers as well.
This gun shoots great in all honesty. I was sure that just cause it was a crosman barrel it wouldn't shoot but a few dime size groups at 55yds says otherwise. Slugs should be here tomorrow but just realized probably won't get to try them until Friday.
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Good luck....but I'd be suspect of anything over .320" in length due to the "standard" twist rateof .177 barrels.
That doesn't limit weight so much as shape. Even at that length (.310-320") could be a decent flat base (Lets say 18.5-19.5gr). And maybe moving at 920-950 fps (lets say 36 foot pounds in a moster-air-,oving PCP) as a maxi-max for an accurate .177.
I've not made it to that level....more like 32-33 foot pounds.
HAve tried Piledrivers...and now that they have been used up in the ONE rifle that shot them well enough to use, can't honestly say I'm sorry to see them go. I did look today for at least a few "left-oversa" to lathe to a shorter length (more like 18-18.5gr) but if any are sill around they are hiding form me.
IF I were to seriously try the really long/wel lshaped/ +20gr. /177's for long range, would likely strat with a faster twist barrel.
With a "normal" (lets say "pellet-wwist":barrel, would keep to 18-18.5gr. or under.
But evwn there, I''ve had deep hollow based/long nosed H&N 16.4gr. pellets "fail"...they have the weight,but also have a too long length for whatever I've tried them in.
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Got a rough tune in today. Not too bad but I'm almost 100% sure will be better with something that's not supersonic lol
Created: 09-12-2018 06:00:21 PM
Description: .177 SS valve
Notes 1: 3175-2300psi
Notes 2:
Distance to Chrono (FT): 3.00
Ballistic Coefficient: 0.031
Bullet Weight (gr): 10.340
Altitude (FT): 0.0
Temp: 70 °F
BP: 29.84 inHG
Shots
# FPS FT-LBS PF
29 1093 27.43 11.30
28 1092 27.38 11.29
27 1099 27.74 11.36
26 1102 27.89 11.39
25 1105 28.04 11.43
24 1111 28.34 11.49
23 1112 28.40 11.50
22 1118 28.70 11.56
21 1120 28.81 11.58
20 1122 28.91 11.60
19 1124 29.01 11.62
18 1130 29.32 11.68
17 1134 29.53 11.73
16 1133 29.48 11.72
15 1137 29.69 11.76
14 1131 29.37 11.69
13 1135 29.58 11.74
12 1139 29.79 11.78
11 1136 29.63 11.75
10 1135 29.58 11.74
9 1137 29.69 11.76
8 1138 29.74 11.77
7 1133 29.48 11.72
6 1130 29.32 11.68
5 1122 28.91 11.60
4 1118 28.70 11.56
3 1112 28.40 11.50
2 1106 28.09 11.44
1 1096 27.58 11.33
Average: 1120.69
StdDev: 15.03
Min: 1092
Max: 1139
Spread: 47
True MV: 1133.06
Shots/sec: 0.16
Group Size (IN): 0.00
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Maybe you have better luck than I do at near transonic speeds at longer range (lets just say anything in the 1030-1100fps range).
Normally, as you expect to do with slugs, will most often switch to a hevier pellet once speeds pass the 4-digiet range.
So far, somthing in the 16-18grain range at somthing close to 950fps (call it 32-35 foot pounds) has worked out better than somthing in the 10-12 grain range at 1100 fps (call that 29 foot pounds). It's not so much the energy as it seems to be the weird sonic-transition velocity zone.
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I need to try some of these new cast pellets in my Prod, they're lighter@23g than the BBT's but I'll bet they shoot good.
(https://farm2.staticflickr.com/1892/43929340454_f34492fef2_b.jpg)
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The NSA 15.5 grain slugs shoot pretty well from my Disco at about 950 fps ...
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Maybe you have better luck than I do at near transonic speeds at longer range (lets just say anything in the 1030-1100fps range).
Normally, as you expect to do with slugs, will most often switch to a hevier pellet once speeds pass the 4-digiet range.
So far, somthing in the 16-18grain range at somthing close to 950fps (call it 32-35 foot pounds) has worked out better than somthing in the 10-12 grain range at 1100 fps (call that 29 foot pounds). It's not so much the energy as it seems to be the weird sonic-transition velocity zone.
Yeah I agree. The only reason I did this tune with the 10.34gr pellets was just I have a ton of them and don't want to waste the slugs once they get here.
The NSA 15.5 grain slugs shoot pretty well from my Disco at about 950 fps ...
Good to hear about that
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Youll gain 7 fpe Min. with the slugs. Thats one mean 177
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Dillon,
I too am watching this thread wanting to see how the JSA valve does ( Unregulated ) and running in the valves sweet spot of 3k - 2.2k pressure on Full size porting against .178" of bore diameter area & @ 16 grains of weight.
watch watch watching (https://www.bmwlt.com/forums/images/smilies/thumb.gif)
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Dillon I'll bet the JSB Beasts or even the Monsters would do got in that gun too.
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There is ALSO the H&N Sniper MAGNUM pellet which is a 15 grain "Semi-Pellet"
(https://www.pyramydair.com/images/PY-P-1220_HN-Sniper-Magnum-Pellets_1513696654.jpg)
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I have those as well Scott and they shoot very good!
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Oh good idea Wayne I completely forgot about the beasts and monsters in .177!
I should try those sniper magnums as well. However only if the slugs don't work then I'll try the heavy pellets.
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Youll gain 7 fpe Min. with the slugs. Thats one mean 177
That's what I'm thinking as well should be a good gain in fpe! And it sure is thanks to the SS valve!
Dillon,
I too am watching this thread wanting to see how the JSA valve does ( Unregulated ) and running in the valves sweet spot of 3k - 2.2k pressure on Full size porting against .178" of bore diameter area & @ 16 grains of weight.
watch watch watching (https://www.bmwlt.com/forums/images/smilies/thumb.gif)
I'm excited to see how it does too Scott! Honestly I can't remember what the ports are on the TP and barrel...guns been sitting ready to test for months. I honestly think it's just at .140 but I'll double check.
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So initial results are promising. Here's the shot groups at 22yds 5 each. Top middle is the 15.5 which were shot first. Bottom left were the 18gr shot second and bottom right 21gr shot last. The "flyer" in both the 18gr and 21gr were the first shots and the following 4 on both went into the same hole so maybe just getting used to the changed slug.
(https://image.ibb.co/e4jOaU/IMG_20180913_140003658.jpg)
52yds this is the 15.5gr the worst of the 3. But maybe shooting these alittle too hot still need to chrony them.
(https://image.ibb.co/nR3o9p/IMG_20180913_135907345.jpg)
These are the 18gr which did pretty well.
(https://image.ibb.co/eSto9p/IMG_20180913_135920074.jpg)
These are the 21gr which I think did best.
(https://image.ibb.co/efVPh9/IMG_20180913_135934816.jpg)
Over all I think they did pretty well and I will try to better them. Just wanted to do some rough shooting with them and get an idea. I only got the sampler pack which had 33 of each and 1 extra 21gr. So I'm already low on them. Will likely be buying the 21gr for sure and probably the 18gr as well.
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Need FPS reading to know whats being over or under shot it might clear up some needed tuning to get tighter groups.
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I too had my SS valve in hand today, made up a transfer port reducer bushing and T port to put valve back into an unregulated .177 M-rod with full bore spec porting.
** What type hammer & weight you testing with ? SSG or TSS too ?
** What size air bleed jet ?
Thanks !
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Will get some numbers this evening Travis!
Scott, excited to see what you come up with! I forget the actual weight but I think in the 26gram range MDS. Stock hammer spring with SSG end cap and 88 jet. Not sure on exact HS setting cause the end cap is threaded so the hammer tensioner can come out all the way.
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Will get some numbers this evening Travis!
Scott, excited to see what you come up with! I forget the actual weight but I think in the 26gram range MDS. Stock hammer spring with SSG end cap and 88 jet. Not sure on exact HS setting cause the end cap is threaded so the hammer tensioner can come out all the way.
That was the primary Q ... 26 mds and ssg.
need to ask travis what the hole size is on a #88 jet ???
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No SSG just standard spring only just the end cap left over from SSG so I can back it out as far as I want. .1025" from what I found on Google is what #88 jet size
So got some numbers...I'm surprised at how close they were to my estimates!
15.5gr at 1000fps
18gr at 933fps
21gr at 850fps
So I'm guessing that the 15.5gr are traveling too fast.
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No SSG just standard spring only just the end cap left over from SSG so I can back it out as far as I want. .1025" from what I found on Google is what #88 jet size
So got some numbers...I'm surprised at how close they were to my estimates!
15.5gr at 1000fps
18gr at 933fps
21gr at 850fps
So I'm guessing that the 15.5gr are traveling too fast.
They might tighten up at 900 fps
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They might tighten up at 900 fps
Yeah that's what I'm thinking
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.102" that is huge ...
Did we miss a decimal point by chance ?
Lol, did a few searches and found that a Mikuni # 89 is at .035" making much more sense and sounding about right speaking with Travis on said subject in the past.
Ok, so i should be able to play as well with a .177 Monster gun here in a few weeks. My plates full the next few weeks no no further playing happening :-[
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.102" that is huge ... like having no jet at all & no corba air spring effect ???
Did we miss a decimal point by chance ?
Well I just looked it up online so could be off. Now that you say that that's way too big. I do know it's an 88 but must not be the size I looked up
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.102" that is huge ... like having no jet at all & no corba air spring effect ???
Did we miss a decimal point by chance ?
Well I just looked it up online so could be off. Now that you say that that's way too big. I do know it's an 88 but must not be the size I looked up
Try this ? .... http://www.historicmotorcycle.org.au/Adler/carby/jets.txt (http://www.historicmotorcycle.org.au/Adler/carby/jets.txt)
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Thanks Scott! So .88mm is what it is so like .035" lol that sounds right
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Dillon, Tofazfou, (Cedric), ordered and had fitted a .172 TJ's bbl and it is a laser. Reaching way out there and getting head shots on G. Squirrels at 130+ yards.
Very impressive! Here's the linky. https://www.youtube.com/watch?v=h0FYdlxgjLg (https://www.youtube.com/watch?v=h0FYdlxgjLg)
Knife
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And for those that like a little more in depth info.
https://www.youtube.com/watch?v=G1cZvv5InKI&t=267s (https://www.youtube.com/watch?v=G1cZvv5InKI&t=267s)
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And lastly---
https://www.youtube.com/watch?v=LrZK5RQYFyM (https://www.youtube.com/watch?v=LrZK5RQYFyM)
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Cedric is DA MAN when it comes to long range pesting…. If I was ever going to build a .17 cal, I would copy his build, and use the same bullets....
(http://noebulletmolds.com/NV/images/N.O.E._Bullet_Moulds_172-26-FN_GC_BM2__Cust.Jpg) http://noebulletmolds.com/NV/index.php?cPath=102_440 (http://noebulletmolds.com/NV/index.php?cPath=102_440)
(http://noebulletmolds.com/NV/images/n.o.e._bullet_moulds_172-26-fn-gc-bm2_sketch.jpg)
He had the mould hollowpointed by Erik at Hollowpoint Mold Services.... It is obviously a DEADLY combination in the TJ's 9" twist 0.172" barrel.... Note this bullet will NOT work in a standard .177 airgun barrel, it is too large in diameter, and too slow a twist rate....
The bullet is a scaled down version of the excellent NOE 225-61 FN (RCBS 22-055) which is about 58 gr. without gas check.... http://noebulletmolds.com/NV/index.php?cPath=24_113 (http://noebulletmolds.com/NV/index.php?cPath=24_113)
Bob
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I have a mandrel being made for the .177 with 9 twist. TJ will have the mandrel at some point. The mandrel has been made twice and has not met spec either time. I guess the small mandrel is hard to make. They charged me a lot of money to make this mandrel too. Mike from TJ's said they are making it again (third attempt) so I have to continue waiting. I wait like 2 months for each attempt so we will see if I get this mandrel before I die.
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Cedric is DA MAN when it comes to long range pesting…. If I was ever going to build a .17 cal, I would copy his build, and use the same bullets....
(http://noebulletmolds.com/NV/images/N.O.E._Bullet_Moulds_172-26-FN_GC_BM2__Cust.Jpg) http://noebulletmolds.com/NV/index.php?cPath=102_440 (http://noebulletmolds.com/NV/index.php?cPath=102_440)
(http://noebulletmolds.com/NV/images/n.o.e._bullet_moulds_172-26-fn-gc-bm2_sketch.jpg)
He had the mould hollowpointed by Erik at Hollowpoint Mold Services.... It is obviously a DEADLY combination in the TJ's 9" twist 0.172" barrel.... Note this bullet will NOT work in a standard .177 airgun barrel, it is too large in diameter, and too slow a twist rate....
The bullet is a scaled down version of the excellent NOE 225-61 FN (RCBS 22-055) which is about 58 gr. without gas check.... http://noebulletmolds.com/NV/index.php?cPath=24_113 (http://noebulletmolds.com/NV/index.php?cPath=24_113)
Bob
Humm, wonder how a Rainstorm II .25 would respond to a .172 build? Hummmm!
Cedric is always chasing the leading edge, or setting it. such a shame we lost him here on the GTA. A real loss for those interested in longer range hunting and AirGunning in general As nice a person you will ever know. We've been friends for many years now.
Knife
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“Cedric is always chasing the leading edge, or setting it. such a shame we lost him here on the GTA. A real loss for those interested in longer range hunting and AirGunning in general As nice a person you will ever know. We've been friends for many years now. “
I’ve been wondering where he went . My ideas where he’s hanging out these days ?
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Pushed aside a no rush project for a stab at this .177 magnum stuff ;D
JSA / SS valve with .039" air bleed, 20 gram hammer with an attached SSG having @ 30 grams total weight, Transfer path throat to barrel @ .170" with elongated barrel port, JSA aluminum air tube, Hogged out gauge manifold topped with a Hill depinger. 3k fill on board. O' and a factory Crosman .177 barrel.
JSB MONSTER 13.43 grain = 1048 / 1050 fps for 32.8 ft lbs :o
H&N SNIPER MAGNUM 15 grain = 997/998 fps for 33.1 ft lbs :o
Yea, I'm gonna need some slugs !
Accuracy testing next.
BTW, the gun fires STUPID stupid stupid quiet ... just crazy (https://www.bmwlt.com/forums/images/smilies/crazy.gif)
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Pushed aside a no rush project for a stab at this .177 magnum stuff ;D
JSA / SS valve with .039" air bleed, 20 gram hammer with an attached SSG having @ 30 grams total weight, Transfer path throat to barrel @ .170" with elongated barrel port, JSA aluminum air tube, Hogged out gauge manifold topped with a Hill depinger. 3k fill on board. O' and a factory Crosman .177 barrel.
JSB MONSTER 13.43 grain = 1048 / 1050 fps for 32.8 ft lbs :o
H&N SNIPER MAGNUM 15 grain = 997/998 fps for 33.1 ft lbs :o
Yea, I'm gonna need some slugs !
Accuracy testing next.
BTW, the gun fires STUPID stupid stupid quiet ... just crazy (https://www.bmwlt.com/forums/images/smilies/crazy.gif)
Very nice! Excited to see what you come up with! I agree shooting mine you'd think it was a standard .177 in the 18fpe range it's crazy. Even when shooting 50-60fpe out the .22 same thing thought It was a standard .22 power from the noise.
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Looking good Scott and Dillon!
I cannot wait until I get home to play with my .177 Cal Prod.
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Pushed aside a no rush project for a stab at this .177 magnum stuff ;D
JSA / SS valve with .039" air bleed, 20 gram hammer with an attached SSG having @ 30 grams total weight, Transfer path throat to barrel @ .170" with elongated barrel port, JSA aluminum air tube, Hogged out gauge manifold topped with a Hill depinger. 3k fill on board. O' and a factory Crosman .177 barrel.
JSB MONSTER 13.43 grain = 1048 / 1050 fps for 32.8 ft lbs :o
H&N SNIPER MAGNUM 15 grain = 997/998 fps for 33.1 ft lbs :o
Yea, I'm gonna need some slugs !
Accuracy testing next.
BTW, the gun fires STUPID stupid stupid quiet ... just crazy (https://www.bmwlt.com/forums/images/smilies/crazy.gif)
Nice power ,
- My ONE-T ( clone of CONDOR ) with .22 air transfer way and 3500 PSIr regulator shots 21gr Piledriver at 950 FPS .I am filling new bottle ( WP:300bar, TP:450bar ) at 3600PSI.
- My Puncher mega shots 21gr Piledriver with .16 oblong transfer port and SS balanced valve at 900 FPS near 3600 PSI.
In another world power I have solved. I am just now resolving only accuracy.
Choked LW and polygonal LW barrel shot them unfortunately not better as 1,5*MOA with 20% flyers and choked Weihrauch barrel poorer.
I am still believe that some producer start to produce some faster TR. Do you have some info about FX liners ?
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“Cedric is always chasing the leading edge, or setting it. such a shame we lost him here on the GTA. A real loss for those interested in longer range hunting and AirGunning in general As nice a person you will ever know. We've been friends for many years now. “
I’ve been wondering where he went . My ideas where he’s hanging out these days ?
Working long hours, 6-7 days a week. :(
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That 1.5 to 2 MOA is about as well as I've ever got the 21gr.Piledrivers to average, and the one rifle that could manage that was not a power house....so pretty well limited use to about 50 yards.
Could get some of the rifles to make speed/energy, but couldn't get them to shoot well enough to be real useful....and if a heavy streamlined slug is going to be useful, it would be at longer ranges (are several"normal" pellets that work fine for ths shorter stuff).
We're in the length area that really seems to want a bit faster twist than standard .177 barrels.
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Here's some .17 casts at a pretty good price.
https://shop.reedsammo.com/Cast-Bullets_c281.htm
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Those look a little small for a .177 barrel. Betting those are for .172 HMR or similar. Might work in an airgun with a .172 barrel like Cedric's HMaiR.
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Not if he knurls it. 8) 8) 8) 8) 8) 8)
When I run slugs in my choked barrel .25 marauder, knurling is the only way I can get any kind of accuracy and no feeding problems.
When you knurl, you can increase the diameter by .01" (high spots in the knurl) so that .172" slug could get as big as .182" when knurled against wood.
Just roll a knurling tool over the slug on a wood board. Super easy and fast to do.
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Fair enough. I hadn't heard of that.
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Here's some .17 casts at a pretty good price.
https://shop.reedsammo.com/Cast-Bullets_c281.htm
$30 for how many ... does not say anywhere i found ???
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Had to work today but tested the 21gr early this morning before work at 55yds and the groups are promising. Planned on more testing but winds are now 20mph with 30mph+ gusts so no more accuracy testing. Also I'm out of the 21gr so going to try the 18gr when the winds die down. Will find my target from this morning to post a pic.
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100 27g .17 Cal (.173") Cast Gas Checked
100 32g .17 Cal (.173") Cast Plain Base
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100 27g .17 Cal (.173") Cast Gas Checked
100 32g .17 Cal (.173") Cast Plain Base
Duh ... too much sun & fun today ... loopy !!
Thank you
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I wonder if you can get the GC bullets Tim linked WITHOUT the gas check.... That is what usually works best in airguns.... That NOE 27 gr. GC without the gas check (and hollowpointed) is what Cedric was using....
Bob
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10 shots at 55yds with the 21gr. Interesting though...first 4 shots were the 4 high one's, next shot was the low right flyer no idea what that was. Next 5 shots were the ones just lower than the group of 4. What I don't understand is they were all shot at the same POA
(https://image.ibb.co/fCLSbe/IMG_20180916_155105232.jpg)
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10 shots at 55yds with the 21gr. Interesting though...first 4 shots were the 4 high one's, next shot was the low right flyer no idea what that was. Next 5 shots were the ones just lower than the group of 4. What I don't understand is they were all shot at the same POA
(https://image.ibb.co/fCLSbe/IMG_20180916_155105232.jpg)
Dillon, Which barrel and velocity ?
Bought my .177 LW ( choked or polygonal - NCH ) barrels shot them similarly or little bit better at 950 FPS . 20% of flyers is adequate for too slow TR.
We definitely need .177 barrels with faster twist rate.
Only Hatsan barrels are different see the video?
https://www.gatewaytoairguns.org/GTA/index.php?action=profile;area=showposts;u=25374 (https://www.gatewaytoairguns.org/GTA/index.php?action=profile;area=showposts;u=25374)
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“Cedric is always chasing the leading edge, or setting it. such a shame we lost him here on the GTA. A real loss for those interested in longer range hunting and AirGunning in general As nice a person you will ever know. We've been friends for many years now. “
I’ve been wondering where he went . My ideas where he’s hanging out these days ?
No Sir I don't. We talk on the phone, and I watch his videos on youtube.
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30 bucks for them is mighty expensive! :o
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Here's some .17 casts at a pretty good price.
https://shop.reedsammo.com/Cast-Bullets_c281.htm
Hard cast and lubed bullets....Maybe not best option..Always can try but if those are hard as .22 bullets which are on same page. 15 and 22 BHN is pretty darn hard for airgun. Just my opinion.
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10 shots at 55yds with the 21gr. Interesting though...first 4 shots were the 4 high one's, next shot was the low right flyer no idea what that was. Next 5 shots were the ones just lower than the group of 4. What I don't understand is they were all shot at the same POA
(https://image.ibb.co/fCLSbe/IMG_20180916_155105232.jpg)
Dillon, Which barrel and velocity ?
Bought my .177 LW ( choked or polygonal - NCH ) barrels shot them similarly or little bit better at 950 FPS . 20% of flyers is adequate for too slow TR.
We definitely need .177 barrels with faster twist rate.
Only Hatsan barrels are different see the video?
https://www.gatewaytoairguns.org/GTA/index.php?action=profile;area=showposts;u=25374 (https://www.gatewaytoairguns.org/GTA/index.php?action=profile;area=showposts;u=25374)
Peter, these were shot from a standard crosman barrel and were in the 850fps range
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Dillon
Was this group shot thru a magazine?
Try a group with a single shot block, or hand fed and see what happens.
I know my Mrod mags cause fliers, which I can't find out the reason why.
Tia,
Don
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I currently don't have any magazine fed air guns but I've mentioned elsewhere that I have seen similar issues in a .17 HMR Taurus revolver that I own. One chamber has noticeably more play than do the others, apparently due to the indexing cut being slightly wider for that chamber. If I avoid that chamber the gun shoots great groups. But if I include that chamber the groups opened noticeably and using only that chamber produces quite large groups. If the magazine in question is free of burs that could damage the pellet, it would seem to probably be related to magazine indexing and possibly some type of impact to the pellet upon chambering.
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Hand fed, rarely use a magazine in any gun.
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Shot without magazine and assuming the scope is good and mounts are good, the way the clusters of shots seem to shift downward, is it possible it is related to change in reservoir pressure causing change in pressure on the barrel?
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Along that thinking .... The SS valves really can shift speed in my testing if the hammer strike is a tad to much. If over striking it fully lifts poppet and stem goes flush with body having the hammer bouncing off the face of valve body.
Not that this is the issue ... just something to look at ???
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Shoot a string and look at the FPS for any speed changes If its pretty steady measure all the bullets OD or use a sizer to get them all uniform.
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If fps is steady and other causes are ruled out and it continues to make two seperate groups over the fill... it can suggest at a certain fill pressure the harmonics of the skinny choked 7/16 barrel are effected...
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If fps is steady and other causes are ruled out and it continues to make two seperate groups over the fill... it can suggest at a certain fill pressure the harmonics of the skinny choked 7/16 barrel are effected...
Might need to tension the barrel.
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Good suggestions guys. Will look into them. Issue is I no longer have the 21gr slugs. Will be trying the 18gr to see how they fair.
I know tune is solid it was when I did the 10.3gr chrony run but maybe not with slugs. Will chrony with the 18gr while shooting groups.
Scopes good have used it on many other guns with no shifts and good BKL mounts.
Pressure change in reservior maybe but idk it's free floated with soft foam around so has some movement and haven't seen any issue of it before.
Would love to tension the barrel but not sure how hard that is on a 7/16" barrel.
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as fill drops the nature of how it gets the round to x fps changes along with the changes in the air tube... can see how it would/could alter a set of resonances sometimes.... a skinny barrel is more susceptible to those resonances...
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Carbon sleeve it Dillon.
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Dillon, I have no experience with the platform you are working with and had only looked at a picture to see the mechanical setup. Picture showed a barrel band from tube to barrel. If yours is free floated then pressure change in the tube should not be involved unless it is velocity related. Chronograph all shots for the group?
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Am NOT SAYING these are "slugs"...they certainly are not (although the 21gr.Piledriver kind of crosses the "slug" line).
But as this has sometimes migrated into that area....
Found some of the missing pictures (OK...were filed under HIPAc rather than "targets","QB's", or "pellets").
Have mentioned it often...but worth repeating rather than have someone think it's something other than just blind-luck.
It's blind luck.
Was built and restocked for one particualr job: fast handling and shooting pest birds at an "up"angle (like they they are in trees), and spent most of it's life down around 8-9 foot pounds for a longer shot count. Was converted to air by way of a HiPac uint (he sold QB verions at one time) to make it more useful in winter.
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/1a38a543-bd5a-4d60-abe7-2730b80f11f5.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/1a38a543-bd5a-4d60-abe7-2730b80f11f5.jpg.html)
No twist difference I can see, cut and recrown to carbine length (is 16.6" if the LDC is removed), nothing specail about the bolt probe, and it is not shooting fast....which is kind of a disapointment, as there really isn't a whole lot of great uses for a slug this heavy and slow.
Like many of the older QB 78 barrels, once you cut it, often find the bore is not quite on center. Doesn'tseem to hurt anything, other than making a good LDC harder to arrange.
(http://i157.photobucket.com/albums/t50/ribbonstone/QB%20mods/796b13a3-ece0-44d2-92d9-038b34d55c9b.jpg) (http://s157.photobucket.com/user/ribbonstone/media/QB%20mods/796b13a3-ece0-44d2-92d9-038b34d55c9b.jpg.html)
Last outing, to get sighted in was at 20 yards. Can tell how long I've been testing various rifles by how rusty the last tin has gotten.
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/450a27f2-b0c6-4302-bb83-75f0b815ef76.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/450a27f2-b0c6-4302-bb83-75f0b815ef76.jpg.html)
Which isn't bad for 20 yards.
So I tried the two other heavy weight pellets that had shown promise in this rifle (there were more tried...but in the reeally heavy weights (15+ grains) the three on the left worked better.
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/00f8c124-18da-4591-a3db-ba90c89ca1df.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/00f8c124-18da-4591-a3db-ba90c89ca1df.jpg.html)
Better day....could get to 25 yards.
URL=http://s157.photobucket.com/user/ribbonstone/media/HiPaC/70f5e451-bc58-473f-8143-95deb7175c6c.jpg.html](http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/70f5e451-bc58-473f-8143-95deb7175c6c.jpg)[/URL]
(BTW: in this case, really never did carry out the 75 yard tests with the 3).
By now, considering the tiny air volume (that's like 72-75CC of air) was getting something like 12-13 good (being 3% or under in velocity varation) shots. So limited my self to the best of the sweet spot...so a refill for each pellet.
Might have taken a few shots to get it "on" at 25 yards, one it was pretty much "on"at 25,then 5 shots for record on the same target. Lot of moving back and forth, but at least pump filling the little tube wasn't a problem.
(http://i157.photobucket.com/albums/t50/ribbonstone/HiPaC/2bd5ed13-8cf6-4307-ab57-ae983730eb9d.jpg) (http://s157.photobucket.com/user/ribbonstone/media/HiPaC/2bd5ed13-8cf6-4307-ab57-ae983730eb9d.jpg.html)
About this point,decided that this rifle really wasn'tgoing to be real userful as a heavy-weight shooter. Accurate enough, but the slow speed/low energy didn't really offer any advanatge at 50 yards...so I just used up the 21gr.Piledrivers in this rifle (although I still think there is a 1/2 tin of them lurking about the place, hiding).
MAy not seem like it...but I really do appreciate the idea of a really high BC slug in .177.All the benifits of windage/range without the "extra" energy if you can launch them at a decent speed.
Just my luck that the one rifle that shot them best was slow(but one slower, the same speed, or way-faster didn't shoot them wellenough for me....just "blind luck".
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PM sent.
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This is the trap I think I fell into.
Finding that one that would shoot Piledriversmake me think there had to be a "secret" even thought it's a simple old QB78 barrel (askinny version from the 78S). If there is a "secret:, it's not twist rate.diameter, coke (or lack of choke), length, velocity, bolt probe shape, probe length, or anything else I can measure.
The "trap"was that it made me ignore the 13-14 rifles that didn't shoot them well as if they were the "freaks" rather than that single example being the "freak".
Not the only time there was the occasional test result that defies all the other results...a "one off".
Not that all of the others were totally wild....some were (tipping and KeyHoles) while others just shoot poorly (but with round holes).
JUst like there is no "perfect"pellet that is a 100% sure bet to shoot well...evidently there is also no "imperfect" pellet that doesn't have some rare rifle that will shoot it.
For what it's sorth, on other froums, when H&N reannounced the Piledrivers, Harry bought up a stash in Austrailia from the orginal UK based company that introduced them. Have no clue if H&N changed diameters or other features, but he was getting much better results with the originals that I ever could(but Yarrah has both skills and some very nicely tuned up airguns).
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Can someone put 21 gr Piledriver put in to Kolbe's calculator with TR: 1:17,7”.
I can not understand why the grouping is better at 980 FPS then at 850 FPS.
At bought velocity I have the same flyers ( 20% 2-3*MOA flyers )
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Can someone put 21 gr Piledriver put in to Kolbe's calculator with TR: 1:17,7”.
I can not understand why the grouping is better at 980 FPS then at 850 FPS.
At bought velocity I have the same flyers ( 20% 2-3*MOA flyers )
My WAG is a faster spin rate of the projectile and the stability it provides when shot at the higher velocity.
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NOE made the shorter version and they even have some with a HP.... 24 gr. FN or 22 gr. HP....
(http://noebulletmolds.com/NV/images/N.O.E._Bullet_Moulds_172-24-HP_PB_CD5.Jpg)
Bob