Sorry, I forgot to add that the magazine box inner lengths are 3.15" for the short action, 3.4" and 3.65" for the long action (the -06 length box has an integrated spacer in the back, but the body and receiver interface are the same). I usually recommend giving yourself .040-.060 space between max COAL and box length to keep things moving in the cartridge stack.

When we acquired the company, it included the parts inventory, so I'm working around existing magazine boxes at the moment. I'm going to have a new LA magnum box made that will accommodate the 300 PRC's 3.70 max COAL when the time comes.

-Ian