At out local monthly 3 gun match yesterday. We had a 24 round slug stage. I was all set to shoot, i had my peep sight zeroed, and i knew where i would do my reloads. I was telling one of the other shooters how much i liked shooting the Wolf slugs and that they worked really well in my 1100CM. I get up to the start box, timer goes off, first shot 'bang' then 'click'. Hmm it must have short stroked. Shot a couple more rounds, same deal. I finished the whole stage shooting then racking a new round into the chamber.
After i was done i thought maybe that i had blown the O-ring or something. Then i remember the previous night when i cleaned the shotgun. Whenever i clean the gun i can never remember that i have to press in the feed latch to release the bolt and operating system from the receiver. I remember something hitting the bench while i was fiddling w/ it. Well it turns out that the thing that hit the bench was the Piston assy. It wont work w/o a piston.
Lesson learned: if you clean your gun, make sure all of the parts get back in the gun.