It is carbine length. Reloads were just short of maximum length. I've never had trouble with any of my reloads of other calibers, always go bang and usually print a dime at 100, at least my 308 does. I think it is that one old magazine. I'm taking others next time. Oh, it would shoot two, and jam the third about half way in. I was only loading 3 at a time to get an idea of the group. May need to load the whole mag and use another mag. I also am going to take this mag apart and stretch the spring to give some tension back. I've also built two others in 223 and haven't had any problems, but I found a few old 20 rounder mags, and thought I would use them on the 300 to be different from the 223 mags, for a little more safety.
