The Glock 30 rnd extension for the G21 mag was design specifically for this
KRISS-TDI.com - Announcing the KRISS Super V CRB/SO .45 ACP Civilian Carbine this will also be one of my next gun purchases I will be able to see my dealers sample store gun in a couple weeks, They will be release for sell to the public in about a month. Since I reload for 45acp this will be allot cheaper for me to shoot then my AR15 and have so much more knock down power, this new rifle can hold a 6 inch group at 100 meters. Can't wait to try one. These mags are not meant for the G21 but I guess you could use one, you may look like you have an extra appendage sticking from your hip.
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