A buddy of mine has a BPS 12ga. bottom ejecting shotgun. He' s had it for about 10 years without any problems until the other day. It jams up firing a 3" shell. The 23/4" work just fine. The gun is chambered for 3" and he shot the exact same 3" shells through it last year. In fact some of the ammo is from last year. Any suggestions, does it sound like a weak spring or something. Any ideas are appreciated.