Ya gotta load one cartridge at a time into the magazine, pulling the follower down just far enough to get it in and push to the back wall. Sloppy loading has caused a few stoppages for me.

Look at the cartridges thru the window. Should look like scales. If the pattern isn't consistent there's usually a loading problem -- and a stoppage.

Or so I've found via my vast experience of a single, 500 round day with the rifle.

-- Chuck