Seeking .45/70 barrel twist rate info


PDA






p2000sk
November 21, 2012, 11:21 PM
All .45/70 rifles I have read about tend to have a slower twist rate barrel, commonly of 1:20". Am I correct to assume that a .45/70 barrel 1:20" twist rate could have a hard time stabilizing a subsonic 500 grain or heavier bullet? Would I want the projectile to be spinning at a higher rpm?

Since I am interested in stabilizing a heavier bullet at subsonic velocity, is anyone aware of any particular make and model of .45/70 rifle with a faster twist rate such as 1:14" on a factory provided barrel?

If you enjoyed reading about "Seeking .45/70 barrel twist rate info" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
.333 Nitro Express
November 22, 2012, 08:49 AM
Hi, P2000SK,

Have you looked at this (http://kwk.us/twist.html) twist calculator? I'll be interested to see what you find out.

CraigC
November 22, 2012, 09:52 AM
Am I correct to assume that a .45/70 barrel 1:20" twist rate could have a hard time stabilizing a subsonic 500 grain or heavier bullet?
Absolutely not! Everything is relative and with big bores, 1-20" is considered a faster twist. It won't have any problem stabilizing any bullet you can throw at it.

Jim Watson
November 22, 2012, 10:04 AM
The US Army settled on a 22" twist for the original 1873 405 gr bullet and found it just adequate for the rather blunt 500 gr bullet of 1881.

Most current production .45-70s have an 18" twist which is good for bullets at least up to 540 gr at black powder velocities (1200 fps or so.)

As far as subsonic goes, the .458 SOCOM is available with an 18" twist stated to be adequate for up to 450 gr bullets and a 14" twist for bullets 500 gr and more. Discussion at: http://www.ar15.com/forums/t_3_121/463281_.html

The .458 Win Mag has a 14" twist for the purpose of stabilizing a steel jacketed 510 gr through an elephant's head.

I know of no factory fast twist .45-70.

p2000sk
November 29, 2012, 09:56 PM
Thank you .333NitroExpress, CraigC, and JimWatson for your responses.
I have looked at the twist rate calculator and discussion over at arf.com.

The .458 Socom chambering for an ar-15 or a used .45/70 lever action rifle is likely in my future. You guys helped me think about it more and in different ways. Thanks again and I'll post a picture after I buy.

Bill_Rights
November 29, 2012, 11:57 PM
Some of us over on another contemporary thread got into these issues in some detail. Check out Theory of barrel twist rate and bullet mass and diameter? (http://www.thehighroad.org/showthread.php?t=685447)

If you enjoyed reading about "Seeking .45/70 barrel twist rate info" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!