Re: Mauser 98 feeding problem
As JE said, the sharp edged belts do try to push each other around, (back and forth). Recoil tries to shift the rounds to the front of the mag well, making them less secure under the rails. When you extract and eject forcefully, it may be that the belt on the fired round catches the fresh round underneath and pulls it back to the back wall of the mag well before it can pop up. Just a possibility.
The .260 is a fine cartridge. The Mauser action is designed for a longer round, but years ago, I had a Mauser actioned .308 match gun that fed flawlessly. The .260 should work as well. Good project.
Good shooting, Tom
Texas State Rifle Association Life Member
NRA Endowment Life Member
A big fast bullet will beat a little fast bullet every time