http://castboolits.gunloads.com/showthread.php?169477-375-Winchester-heavy-hunting-load
Not to throw the thread off track, but have you looked at the 375Winchester or the 38-55 ? They come with a 1 in 12 twist for the 375, or a 1 in 18 for the 38-55. They can handle bullets from 200 to 350 grains. They are available from Thompson, Winchester, and Marlin. I have included a link for your reading pleasure.
Not to throw the thread off track, but have you looked at the 375Winchester or the 38-55 ? They come with a 1 in 12 twist for the 375, or a 1 in 18 for the 38-55. They can handle bullets from 200 to 350 grains. They are available from Thompson, Winchester, and Marlin. I have included a link for your reading pleasure.