My friend Brian Miller is a firearm tinkerer. He has a milling machine and a 3D printer and makes his own custom parts for his guns. He made a coupler to connect two Vepr 12 magazines end to end, so it becomes one giant magazine. He has made custom optic mounts as well as muzzle brakes for his Vepr12.
Well recently Brian had an idea to add 8 rounds to a Colt SMG magazine. I think my +10 extension for the CZ Scorpion magazine may have inspired him. Colt made a 9mm AR back in the 80s. It was fed with a modified Uzi magazine. Due to the new USPSA Pistol Caliber Carbine division being made official, pistol carbines are becoming increasinly popular. It is not uncommon to shoot a USPSA match where a stage or two have a round count north of 30 rounds. So having 8 more in a 9mm AR is most welcome. Since the Colt SMG mags typically hold 32 rounds, this extension makes it a nice even 40 rounds.
I am now more eager for an IWI X95 9mm conversion kit so I can use Brian’s extensions on their mags.
At the moment they are not available for sale.