308 Twist 1:12

[BlueSmoke]

Why is a 1:12 twist somewhat standard in 308 WIN rifles?

Is that fast enough to stabilize 170 - 180 grain cast bullets at moderate velocity??

Say 1400 - 1800 fps.

Thanks,

BlueSmoke

[felix]

More than enough twist. Even at those velocities 13 would do fine. ... felix

[Firebird]

Here's a twist calculator (http://www.kwk.us/twist.html) that also includes some explaination.

[Larry Gibson]

in .308s with 12" twists I've shot many a sub moa group at 100 yards with 311291 and 311041 both of which weight 177gr+ when cast of WWs + 2-3% tin within those velocity ranges. The RPM of 1400-1800 fps is 84,000 - 108,000. I've also shot many a 1150 fps 1" group at 50 yards with both of those bullets over 6 gr Bullseye. I am currently experimenting with 311291 in a 14" twist barrel and have had no problems with stability. I will see how low a velocity I can shoot a 311041 for use as a "cat's sneeze" load at around 800 fps one of these days.

Also keep in mind the .32 Special has a 16" twist and doesn't have stability problems with 170 gr bullets.

Larry Gibson

[Char-Gar]

Most 30-30s also come with a 1-12 twist and do well with cast bullets up to 190 grains accross a broad range of velocities.

[sundog]

My .308 700 VS seems to like the 31141 very well. Furthest shot with it to date is 200. The 12 twist does just fine.