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Old December 25, 2012, 08:34 AM   #7
Bart B.
Senior Member
 
Join Date: February 15, 2009
Posts: 4,985
Dan Lilja's twist chart is pretty good, but for 30 caliber bullets 180 grains and heavier needs some adjustments.

Folks shooting 30 caliber magnums pushing out 190 and 200 grain bullets at about 3000 fps from 1:12 twist barrels in long range matches won a lot of them and set records, too.

I had a worn out .308 Win. Palma rifle 30" barrel cut off 2 inches at the back end, 1 inch of the muzzle end then rechambered for .300 Win. Mag. It shot 180-gr. bullets leaving about 3000 fps about 1 MOA at 1000 yards from its 1:13 twist barrel.

Go figure out why. You may end up learning that the rpm rate a bullet spins is the critical thing about bullet stabilization and accuracy. Faster bullets from slower twists shoot just as accurate as slower ones from faster twists.
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