help with Twist

Y

Yeti

Guest
How does one go about deciding what is the best twist rate for a given caliber, pellet weight, speed etc

While on the subject, how do you choose the most effective, (accurate) bore diameter?

Thanks

Cuan
 
I have been searching for information and there is enough on center fire guns to give a layman such as myself a serious migraine

But there seem to be no guidelines for air rifles ?

Can anyone point me in the right direction?

Please ?
 
Greenlee formula is as applicable as any thing. Unless you are working on something outside the box the rate of twists that the mfg's use is hard to beat, time proven.
 
I've never found any published info on airgun twist rates. I suspect it is not as important as with powder burners due to the self stabilizing pellet. Here are some rates that I've measured and read. LW barrels and BSA have a 1:18" twist rate, HW are about 1:15". My .22
smooth twist has a 1:156" rate, yes that is 13 feet. The Benchmark barrels
cut for airguns have a 1:17" rate. I believe that Whiscombe's had a slow
rate of around 1:30". Benjamin marauder 1:16", .22 cal.
Hope that helps.
Dan
 
DanB said:
I've never found any published info on airgun twist rates. I suspect it is not as important as with powder burners due to the self stabilizing pellet. Here are some rates that I've measured and read. LW barrels and BSA have a 1:18" twist rate, HW are about 1:15". My .22
smooth twist has a 1:156" rate, yes that is 13 feet. The Benchmark barrels
cut for airguns have a 1:17" rate. I believe that Whiscombe's had a slow
rate of around 1:30". Benjamin marauder 1:16", .22 cal.
Hope that helps.
Dan
Click to expand...

How you calculated the resulted twist rate of a pellet, that was propelled in a smooth twist barrel?

From my experience with my airgun (Gladiator 5,5 MKI@30ft/lb), I would say the resulted twist rate of a 16gn. domed pellet is about 1:8'' - 1:9'' (by Muzzle Velocity:282m/s) ....and I suspect this ratio from the drift of POI on the paper. The estimation procedure is quite simple....all you need is a good ballistic program, with spin drift calculations enabled.

To be honest, I cant imagine how you calculated such a slow spin....maybe at lower power levels? and how?

Thank you in forward :)
 
http://www.network54.com/Forum/79537/thread/1276988390/Smooth+twist+or+no+twist+at+all
http://www.network54.com/Forum/79537/thread/1277076002/Smooth+twist+rate+confirmed

Goldwhisky said:
How you calculated the resulted twist rate of a pellet, that was propelled in a smooth twist barrel?

From my experience with my airgun (Gladiator 5,5 MKI@30ft/lb), I would say the resulted twist rate of a 16gn. domed pellet is about 1:8'' - 1:9'' (by Muzzle Velocity:282m/s) ....and I suspect this ratio from the drift of POI on the paper. The estimation procedure is quite simple....all you need is a good ballistic program, with spin drift calculations enabled.

To be honest, I cant imagine how you calculated such a slow spin....maybe at lower power levels? and how?

Thank you in forward :)
Click to expand...
 
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