Anthony,
We are currently working on an extension design for the M4, but have not had much call for the M3. If this changes, we will certainly look at manufacturing an extension for the M3.
Regards,
Jeffrey Hajjar
President & CEO
SRM Performance Products
A Division of Snake River Machine, Inc.
208.887.9395
www.surecycle.com
IF you are a M3 owner and interested in getting a mag extension for your gun, email Mr Hajjar. There must not be enough demand for them to start producing extensions. BTW if youve got a 2 round extension for the M3 and want to get rid of it, let me know