Twist Rate for .338-.378 Weatherby?


New Member
Mar 9, 2003
Western Oklahoma
My local gun shop has a 338-378 custom built on a Winchester model 70 with a Hart barrel. The guy that built it had the smith put a 1-12" barrel on it to shoot the lighter 165 grain bullets at 4000 fps. The gun is priced right but I would like to be able to shoot the 300 grain SMK's. What twist rate does it take to shoot the 300's???


Well-Known Member
Dec 4, 2002
Northwest MN
Typically, for the 300 grainer, you'll want a 1-10 twist. Actaully, a 1:10.5 WILL stabilize the 300, and a few people have claimed to do it with a 1:11. If you visit Dan Lilja's website and read his article on atmospheric conditions/changes, you'll understand why. Bottom line: 1-12 twist is not optimum for a 300 grain .338 bullet--it probably will not work, and if it does, it is almost certain to lose stability at the longer ranges <I'd venture a guess that anything over 700 yards to be...very difficult at best.> Having said that, IF the weapon is priced quite right, it will handle the 250 grain match bullets, and for ranges out to about...oh, maybe somewhere around 1100 yards, maybe a bit more, depends on some factors, that bullet will do all the 300 will. Past that, the big Cheese takes the lead, but still...that 250 grainer is nothing to sneeze at, and it does have capabilities beyond 1100 yards under good conditions. All here will tell you the 300 is far superior, and it is; I shoot it.
BUT--if that other gun is priced low enough, get it--it'd be fun, and might perform astonishingly well at 1000 yards and closer.