They aren't really "Colt's" specs....Colt bought them and claims they are theirs.
I don't use PMAGS. I had some 20 rounders and sold them to buy pre-ban GI 20s. (adventure lines) I pretty much use 30 round GI mags exclusively (most of mine are Centers and Okays) upgraded with the grey magpul followers. Most reliable magazines I've ever had, not one malfunction in years.
HK and some enfield magazines are steel.