I had this same problem on an older model 64 I have. I used it for coon hunting for years with never an issue, then one year it started jamming like this every other round. After cleaning everything and still having issues a friend suggested I clean and lube the magazine itself. Turns out years of walking through the woods gets a mag full of grit and it will stick so bad it doesn't push the next round up. Might try lubing your mag