My Aero Precision/Surplus Ammo & Arms lower got here today. It had a nice low serial number to boot. It looks really well made. Especially since I picked it up during a group buy for $65 delivered. Just for giggles, I wanted to do an impromtu test to check the tolerances. I inserted an early version magpul mag, and placed a partially stripped Bushmaster A2 upper to check it out. The (loaded) magpul mag dropped free and felt nice. I didn't take the time to unload the mag and check but I think that it would drop free empty as well. I also tried 3 Colt mags. 2 of them would drop effortlessly, though in defense of the lower, the mag that didn't drop free has a lot of rub marks on the corners from previous use in other guns, so it may've been a little out of spec from dropping it while doing speed reloads. Though I don't remember having a problem with any of the Colt mags previously, but I'll keep an eye on that one mag in the future and have moved it to the range only mag drawer in the meantime. 3 of 3 OK Center mags dropped free 3 of 3 D&H mags dropped free 3 of 3 asian import mags dropped free Both Orlite mags failed to drop free. One of them didn't even want to go in, but I've had those mags for a very very long time and I don't remember using them in years, so they're probably at the end of their service life. I got them out of the range drawer just out of curiosity. A Bushmaster 10 round ban mag also dropped free I appreciated the fact that the magwell had very nice defined square corners (inside) that were not as rounded as some others I have seen. The pin holes lined up perfectly with the spare upper. All of the other upper/lower mating surfaces were good too. The only thing I noticed that may be an issue for some folks (not me) is it had a high shelf that would need milled if anyone were to try to use a dias or LL with one. The anodize is mediocre and isn't as thick as some lowers I've seen and thicker than some others. Overall, on a scale of 1-10, I think it would be about a 4. That is my biggest drawback with it, but for the most part, I think it's fairly adequate. I think I have decided on a 7.62x39 Model1 upper for it. Cut back to 19.5 inch barrel and rethreaded for 1/2-28 so I can use my suppressor on it when I want to. Flat top upper, freefloat, etc. because I plan to make this my medium/large game rifle. I also plan to get a camo dip kit when it gets closer to time because I am a big fan of the Natural Gear camo pattern because it works so well where I hunt But it'll be a long while before I can start on that, but I think this lower will be a good base to build on. I just wanted to give you guys a heads up that the Surplus Ammo & Arms (made by Aero Precision) lowers are pretty decent for the cost if any of you were considering one to buy. And just because I know, pics or it didn't happen.