Originally Posted by
DavePAL84
USGI's are cheaper for one (although I certainly wouldn't call PMags, 'expensive' by any means) which means you can buy more of them. Magazines are consumables and should be treated as such.
USGI mags are just fine so long as you don't have any with black followers. Magpul followers are better than the green ones certainly but I haven't had too many problems to begin with that could be specifically tied to green followers.
One of the big problems with USGI mags is that people generally don't toss them when they go bad. Get a doublefeed? Crush it and move on. During the AWB people kept their so-called, "high capacity" (read: standard capacity) magazines far after their service life was over. Magazines are so cheap now no there's no reason not to have a bundle.
Some pouches have a hard time with PMags. Since they are slightly wider and because the baseplate is larger than the mag OD, occasionally, with some pouches, two mags will come out when you're only grabbing one. PMags have been out long enough that it isn't the case with all of them but you gotta try them out first.
Some rifles will have a hard time closing an open-bolt on an inserted PMag (bolt release doesn't work, have to use the charging handle). One of my friends stopped using PMags once this started happening. This was with the series 2 PMags IIRC. (I've seen this with three rifles: my buddies LMT, a Colt 6920 and a POF (the latter two were from students in a class)).
You can use the corner of a USGI mag to force back a stuck bolt. Of course, you can't do that with a USGI mag if you have a ranger plate installed.
Won't drop free from all lowers, however, that issue is mostly fixed. If you have some old lowers it may be an issue. My suggestion would be to borrow some PMags and see.
One of the good things about polymer magazines is that when they fail, you can see it (cause they crack or split down the spine). Feed lips on USGI's aren't so obvious when they are out of spec (usually the first sign is a double feed unless you check them all first).