I have a mossberg 500 3 barrel combo. While shooting slugs thru the rifled barrel it pumps very smooth and easily. But while shooting trap with the 28" vent rib it is very hard to pump after I've shot. I've even had to smack in on the ass end to get it to pump back a couple times. If I haven't shot the forend slides fine with either barrel.
Anyone have any ideas on what would cause this?
Anyone have any ideas on what would cause this?


















































