Running a Pistol Caliber Carbine that takes Glock magazines?  BGs is now introducing extended pistol mag carriers designed specifically for use with PCC Glock magazines.

They offer lower carry height than the classic pistol magazine carriers and better protection of inserted magazines, but will sill fit anything from 15 round to 33 round Glock magazines. Magazines are reversible, so the shooter can carry shorter magazines with rounds facing forward, or longer magazines with rounds facing back. Magazine carriers feature an enhanced cut for faster draw and tactical reloads and have universal mounting hole pattern, which is compatible with most standard attachments on the market and offers additional carry angle adjustability.

Already available at Aawee.fi and Polenar Tactical Shop.