I run Colt AL mags (2), C-Products Steel (2), Triple K 9rd AL (1), Surplus AL 20rd (1), Gen 2 P-Mag (4), and Gen 3 P-mag (5). All run just fine. I had to modify the lips on the Triple-K to get it to feed, but after that it's just fine. The AL's ar the lightest, but the P-mags are my go-to mag now. It's like when I have a friend that has a 1911 that keeps having feeding problems. I let him borrow one of my McCormick's and suddenly the gun will run. If I have someone that has an issue with an AR that won't run, I let them try a P-mag and all is well. They are a bit more bulky than the other, but they are reliable and I'll take that over weight and bulk anyday.