Bullet/Pellet Weight Preferences
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Bullet/Pellet Weight Preferences
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Topic: Bullet/Pellet Weight Preferences (Read 1271 times))
Wildernesstech
Shooter
Posts: 92
yes
Real Name: David
Bullet/Pellet Weight Preferences
«
on:
December 13, 2014, 09:28:37 AM »
I am trying to figure out whether the barrel twist of 1 in 15" for .45 caliber will favor lighter and faster (150gr) or heavier and slower (200gr)? From what I can deduce, the barrel twist is likely too stable for either, but I can't quite connect the dots...
My planned usage for this airgun is purely hunting, so placement will be the key, but which has the best reaction to bone met upon impact will come into play also. You never know when a mistake will happen.
Also, the effect that is had on the gun itself comes into question; Does the heavier bullet cause higher pressures that stress the airgun and make parts age faster?
Trying to pick just one bullet that does it all... Yep, I know that there are no magic bullets, but best choices still exist.
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The Ozarks
rsterne
Member 2000+fps Club
Bob and Lloyd
GTA Senior Contributor
Posts: 26958
GTA Forums Person of the Year 2017
Real Name: Bob
Re: Bullet/Pellet Weight Preferences
«
Reply #1 on:
December 13, 2014, 02:58:42 PM »
A 15" twist for a .45 cal is ridiculously fast.... A roundball will need about a 70" twist, and a 1-caliber long bullet (~170 gr.) will only need a 56" twist.... A 200 gr. is still very short, and will only need about a 48" twist.... You need to get up into a 500 gr. bullet (or a slightly lighter boattail) to even think about a 15-20" twist in .45 cal....
A heavier bullet doesn't "stress" the airgun any more, but increasing the FPE to try and drive it at a reasonable velocity might....
Bob
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Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
Wildernesstech
Shooter
Posts: 92
yes
Real Name: David
Re: Bullet/Pellet Weight Preferences
«
Reply #2 on:
December 14, 2014, 07:21:01 AM »
Thanks for confirming my thoughts... I bet she will keyhole nose-up at distance. Maybe a rebarrel is in the future? If I am not mistaken, a slower twist should up the FPS too!
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The Ozarks
rsterne
Member 2000+fps Club
Bob and Lloyd
GTA Senior Contributor
Posts: 26958
GTA Forums Person of the Year 2017
Real Name: Bob
Re: Bullet/Pellet Weight Preferences
«
Reply #3 on:
December 14, 2014, 01:44:09 PM »
Well you will never get a keyhole from too much twist, even at only 700 fps the angle of impact at 100 yards is only 3/8" per yard compared to the departure angle.... With the bullet only being 1/2" long, that means the hole would be elongated only 0.005" vertically, you would never see it.... What too fast a twist does is exaggerate any imperfections in the bullet, particularly balance, causing it to wobble more and the cone of dispersion to therefore increase.... The better the quality of the bullet, the less effect spinning it too fast will have.... I don't think you will notice much difference in velocity with a slower twist....
Bob
Logged
Coalmont, BC, Canada
🇺🇦
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since! 🇺🇦
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), XS-60c HPA in .30 cal (90 FPE), .22 cal QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Benchrest PCP, .172/6mm Regulated PCP and .224/.257 Unregulated, Three regulated BRods in .25 cal (70 FPE), .30 cal (100 FPE) & .35 cal (145 FPE), .257 Condor (180 FPE).
Wildernesstech
Shooter
Posts: 92
yes
Real Name: David
Re: Bullet/Pellet Weight Preferences
«
Reply #4 on:
December 14, 2014, 09:12:39 PM »
Thanks, I will try to be picky when it comes to ammo quality... I haven't cast in 30 years, so I'll bet my first tries will be sub-standard anyway, but such is life. From what I have seen so far other owners of this model are happy with the accuracy, so only time will tell. I appreciate your input. Thanks again!
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The Ozarks
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GTA
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All Springer/NP/PCP Air Gun Discussion General
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PCP/CO2/HPA Air Gun Gates "The Darkside"
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Bullet/Pellet Weight Preferences