I have 2 belted cartridges in rifle with internal magazines, I must be more anal when I'm loading them.Here is a first world problem.
While I own three different belted mag guns, the thing I don't like about them is that when you load the magazine (all of mine use magazines) the round slides back and then hangs up on the belt of the round below it so that it is hard to seat against the back of the mag.
Horrible, I know.