I had two first gen pmags work perfectly. But others then those two specific mags no other mags I have tried work. Other gen 1, gen 2, lancers. I could not bring myself to cutting up a window one to try it. So I went to cproducts mags now and I just make sure the feed lips are the same. That was the only problem I have had with the cproducts. One side of the lip on one mag was a lil to high. Bent it down to match the other and now flawless. So one lil tweek to one mag and other 34 work fine. I plan on just sticking to the cproducts then messing around with others.