I purchased a used 11-87 Super Mag back in the fall, and finally got a chance to shoot it 2 weeks ago, only to find out it won't cycle.
I tried heavy 2 /34" as well as 3" shells - no cycle.
When I bought the gun, it had an odd setup in there - piston/piston seal, activator (for 2 /34" shells), then TWO rubber gas chamber seals instead of one. I never shot it in this configuration - first thing I did was order and install a new piston seal kit from Brownells (figuring it would be a good thing to do with a used gun - yeah me.)
I have spent the last 2 hours trying every configuration I can come up with from the used and new parts, and was only able to get it to cycle ONCE, and that was with the used piston, activator, and two gas cylinder seals. I tore it back down to try the NEW piston, only to get a half cycle (shell caught in the chamber in ejection). Ever since then - no combination works, even the one I got to cycle once.
Does anyone have any tips to try? This can't be rocket science, and I hate the idea of paying a gunsmith to do this for me...