The story: Went to the range today with my Colt combat commander lightweight. I took a small bag of ammo with me, IDK where I got the ammo. As I pulled rounds I came across a few 40s and a 9MM along with the 45 ACPs. You see where this is going dont you. So yes I got a 40 in the mag with my 45 ACP rounds. Shot a few rounds and heard a strange report from the gun. Some of my rounds were reloads so I suspected it was a light load. Next thing I know I press the trigger and nothing. I tap and attempt to rack and the slide is stuck. I take it to the bench and after some work I get the round out and sure as hell its a 40. Looking over the gun I notice the firing pin block is gone and the firing pin is stuck forward. I strip the gun and, there goes the firing pin with spring flying out. I attempted to find the block but no luck. So what do you think happened, other than me being a dumb ass?