I finally got my AR. So, I was finally able to get to the range to try the various mags that I have been buying.
All the Pmags, Lancer, Brownell's, Stoner, and GI mags work perfectly.
All three C-Prod 20rd SS mags had 100% problems. Not one functioned at anytime without some type of problem. Either the last round would pop-out of the mag when the second to last round was ejected or one corner of the follower would (slightly) stick out of the body and cause the bolt NOT to stay open after the last round.
The one SS 30rd worked flawlessly some of the time (50%). HOWEVER, if I loaded only 5 rounds, the first round would get caught on something and not load. 4 rounds- OK, 6 rounds-OK, 10 rounds- OK. Seems to be an odd number of rounds/loading from the left side problem.
The two Al 30 rounders had the same results as the SS 30rounder.
All C-Product Mags have the orange follower. All the C-Prod mags fit fine in my receiver (M&P15).
So when, I send them back - what should I ask for? 30 round SS v. 20 round AL v. different color follower?
I'd rather get my money back, but I know that is not likely.
I ordered C-Prods 01.04.2009, because at that time, it was one of three manufacturers that were recommended on this forum.
I would have NEVER ordered them, if I the feedback was as bad as it is now.