HELP! I was firing in the new Nikon M-308 scope (love it). New gun also S&W MP10 .308 (did love it), bought it on gunbroker.com. The bolt hold back knob blew out, I can't believe it! What now? Any advice?? It looks a bit damaged inside the hole for the knob, I found three parts, the knob, a spring, and a pivot lever that fits in the knob, anything else missing? Oh my! Guess I'll need a gunsmith here. Bummer!