Olympic Arms provides a one piece magazine that does not require any separate hardware.  Just insert the magazine into your lower with your pistol caliber upper and start shooting!

Magazines are available for: 9mm, 10mm (10 round), .40S&W  (10 round) and .45ACP (10 round).

The 9mm is based upon the STEN magazine and the 3 others are based upon the UZI magazine.

9mm magazines can be special ordered for states that require 10 round or 15 rounds.  Special orders take at least 90 days.