A question for those of you who have tried out either the "plumcrazy" or "new frontier" lowers. Do they use a mil-spec or a commercial buffer tube and can they be changed out to an aluminum one?
They've been fine for what I've used them for. I wouldn't trust one with my life just because they haven't been proven like the aluminum ones have. They should accept any aftermarket buffer tube. If you are replacing the buffer tube it doesn't matter if it's a commercial or mil-spec buffer tube. It only matters when choosing a stock.