This information was originally posted on our forum by LDD. Please understand that LDD and NYFirearms.com or its staff are not firearms experts, law enforcement, lawyers, legal experts or anything of the sort so this information should not be taken as legal advice. The observations regarding date stamps on magazines described in this post are just that, observations based on examining several magazines and are not intended to be taken as absolute fact. As always, please consult a qualified legal expert if you are unsure of any laws or regulations.
If you are looking for a really durable, bomb-proof magazine, then I’d point you to the Chartered Industries (CI) and Imperial Defense (ID) steel 30 round magazines. These are NATO standard dimensions, but the ID mags were intended for the Brit’s SA-80s. IIRC Singapore uses a mix of rifles that include M16 pattern and their own domestic bullpups. Both fit in properly spec’d US AR15s without modification.
Chartered Industries Mags:
The downside of the CI and grey ID mags is the prebans shipped with blue followers that were complete crap. They were shaped like our green/orange followers, but made out of a plastic that has the consistency of a gummy bear (they would bow inside the mag body: bow in front = follower hangup; bow in back = bolt doesn’t lock back on the last round).
I replace these blue followers with Magpul followers as a matter of conscience, before I sell them (they are that bad). The CI mags may require you to grind a little of the MP followers away before they will fit (front baseplate retention tabs on CI mags are oversized compared to USGI mags). MP followers fit the Imperial Defense mags without modification.
Imperial Defense Magazines (subcategories: Black and Grey):
Did some more research on these, including contacting some folks that used the black magazines for wildcat builds during the ban. I knew the grey ones were preban because I bought a batch during the ban (at “preban” prices too). Personally, I never encountered the black ones till after the ban but have since spoken with builders, who, as I said, used the black 30 round mags for wildcat AR builds.