Honestly I can say that I've ever used that cmmg kit. I've only bought a bunch of dpms spare parts. they've saved the day when I've been out on a desert shoot when I'd otherwise would have had to call it a day. It'll do in a pinch. As for preventative maintenance, I'm a new shoote with only afew thousand rounds down tghe pipe so my gear has yet to get run down. But id assume only changing detents and springs as things start to loosen up. I can't see there being much of a difference in those parts to be honest. The bolt and firing pin on the otherhand....

