well, i got my M2 conversion up and running today, it's even more fun than i expected. instead of buying headspace gauges to check the new round bolt i took it to my smith and had him look it over the gun while he was at it. only set me back $10. i reassembled the bolt and installed it with the registered trigger group and all the M2 conversion parts and test fired it in the back yard. runs like a very noisy sewing machine. great fun! I can see already i'm going to need a compensator.