Finally got a chance to try these out. The magazines function flawlessly. As for Remington shells, the Express Long Range worked almost perfectly, with one stovepipe out of 50 shots. The Remington Game Loads stovepipe every time, just like any Federal 2-3/4" shell.
So, I think there is something to csspecs' theory about hull weight, but it isn't the only factor, as both types of Remington shells appear to have the same amount of plastic.
My gun has not had any additional drilling done to the barrel, just a polished bolt.
Anyway, I'm pretty exited to have these magazines and shel