Marlin 30-30 re-bored to 38-55
 

Anyone had this done? Not looking for where or who but actual target/field usage .What groove size ,bullet weight and twist did you go with and why?

I have replaced the barrel to make a 38-55 because it was a lot cheaper than a re-bore of the wore out 30-30. Your other choice is to make it into the modern version, the 375 Winchester. The way you have a true .375 rather than a .378, which is hard to find jacketed bullets for. If you want to shoot just cast then it doesn't make much difference whether you go 375 or 38-55..

think I know what I want now
 

Win 1894 used 1-18" while Ballard 1-20" twist.I talked to JES in the States and he does almost all his 38-55's at .376 groove and a 1-15 twist.These handle all bullets that will cycle through a lever.The Marlin 336 isn't recommended as a .375 win conversion [even though Marlin made them briefly] depending on your sources 336 run at 35,000cup with extraction issues at 40,000cup The .375 runs near 50,000cup with a 1-12 twist.Whether this has to do with year of manufacturing no idea.Lots of controversy.

pressure chart