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Old December 17, 2012, 10:40 AM   #4
kraigwy
Senior Member
 
Join Date: June 16, 2008
Location: Wyoming
Posts: 9,360
A rule of thumb is:

The Faster Twist will stabalize light bullets, the slower twist will not stabalize heavy bullets.

Meaning a 1:7 can shoot 80-90 gr bullets, but it will also work with 50 gr bullets.

A 1:12 will stabalize the 50-55 gr bullets but will not stabalize the heavier bullets.

For an example, the 5.56 Mann device (used for testing military ammo) is a 1:7 twist. The ammo used to check the Mann is 52 gr Match bullets.

The below chart shows the army shooting 300 yard targets with heavy bullets in a 1:12 and light bullets in a 1:7.

If you have a choice, go the fasted twist you can. You can shoot 50s to 90 gr bullets.

Many say that the fast twist will over spin lighter bullet causing them to come a part, this may be true if you use light 40 gr pills designed for the Hornet, but any good quality 52-90 gr bullet will work with the faster twist.

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Kraig Stuart
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USAMU Sniper School Oct '78
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