Got my rarebreed fart in the mail. Installed in about 10 minutes. It really is plug and play. Punch the pins out and slip thr cassette in. The cassette is held in with threaded pins so no risk of walking. The only hiccup was i had some trouble closijg the upper on the lower. A quick google seqrch indicates the reset bar was interfering with the BCG. I was able to solve it by closing the gun as much as possile and slipping a knife between the upper and lower and pushing the reset bar forward. That allowed the uper to close the rest of the way. That's concerning to me from a field expedience standpoint but I'm not larperating yet so whatever. Something to cinsider thiugh if you want this is a combat gun. Apparently this is only an issue with some BCGs and if you shop around you can find one with a geometry where this isn't a problem. Will report back when i go to BLM land next week and test it out.