We were all at the outdoor range and I look over at my buddy shooting. He tired to fire a round and *click* nothing happens, so he waits like 5 seconds (n00b) racks the round out and goes to fire another one, same thing happens. He does this three times and finally on the 4th time the gun goes bang. So I tell him to wait at least 2mins between misfires and to keep the gun pointed down range. The next time the gun does the same thing except it only misfires twice then goes off on the third round. I asked him if this was a normal thing with this gun, he said that the gun only had 3-400 rounds and he's never cleaned it because he didn't know how but it's never done this before. I field strip the gun and it looks fine just dry. We went to my house and I cleaned the gun for him and told him to contact Sig asap. The WWB he was using looked fine and I couldn't see anything wrong with the firing pin, then again I'm no gunsmith Any ideas what happened?