I bought 10 all dropped free and functioned just fine. If your not loading long these are great mags. Most of my shooting is xm68 or 120sst taco try loaded ammo so I decided to get 10 more for a total of 20.
Are they as good as PRI? We'll sort of depending what your doing. I have around 10 PRI mags of varying sizes. All function the same with factory ammo and drop free just fine.
I like them a lot. the sheet metal is .010" thicker than ASC and CPD. They are very stiff and strong like the PRI. They are lap welded like the asc and CPD, so you cant load out 2.30 like the PRI.
I use them for extra long loading by cutting the front out, and shortening them. If you screw one up your only out a few dollars. You can tweak them in a vice to stop the rattling if that bothers you.
All of mine drop free from the lowers that I have.