CompMag AR15

From the manufacturer:

"Compatible with .223, 5.56, .300ACC Blackout, and .277 Wolverine Ammunition.

Compatible with standard AR-15 type lowers. (M4, M16, AR15).

Compatible with other firearms that accept a STANAG (AR-15) magazine and have a removable upper receiver; including the SCAR16, CZ Bren 2 (5.56), Bushmaster ACR, SIG MCX, SIG 556, Galil ACE, BRN180M, Springfield Saint Edge ATC, and Daewoo DR200.

NOT compatible with lowers that have a custom or extended magazine well (such as Seekins SP225, Sharps Bros, HK MR556, HK 416, and Spike's Jack).

Not compatible with most bullpup firearms such as the Tavor and Steyer AUG as you cannot separate the receiver to remove the CompMag without destroying the magazine. We are working on a retrofit kit for the Hellion but as of now it does not lock in to satisfy AW compliance as the magazine sleeve is removable."