Hi guys I am looking to have a 50 caliber rifle built and am trying to decided between a 50-70 and 50-90.
I want to shoot heavy bullets, mostly for their higher BC. At the moment I am considering a design that will weigh in around 645 grains! The rifle will be heavy around #18, with a 28" barrel.
I never like to take these things by gospel, and value real experience above all theory; but from running Quickload to achieve by desired velocity of between 1300-1450 fps to keep pressure below 20kpsi I need to breech seat with the 50-70.
Whereas with the 50-90 I may be able to reach 1400-1500 fps using fixed ammo and possibly 1600fps with breech seating.
I am not saying that I have to drive them at 1500 fps, but asking if the 50-70 can satisfactorily drive a 645 grain bullet and do well at 300-500 yards or is a 50-90 needed?
I might add that I can only get a 20 twist, which is faster than ideal, but getting a 50 caliber barrel exported is hard out of America and the slowest in Australia I can get is 1:20:though I think 1:26 would be better.
I know that the 50-90 is more versatile, and I may be able to loan a reamer, but the brass is so much less available and so much more expensive than 50-70.
In short I am asking for advise on if the 50-70 is enough case for a large bullet.
Thanks