Cmmg's 5.7x28mm, 40rd 5.7 ar conversion magazine fits in any standard ar15 lower receiver.To use, simply attach a cmmg 5.7x28mm radial delayed blowback complete upper receiver to an existing ar15 lower.Then, insert cmmgs 5.7 ar conversion magazine to safely feed 5.7x28mm ammunition.Cmmg recommends using a standard carbine buffer and action spring to reliably cycle the action in this configuration.The 5.7 ar conversion magazine also retains last round bolt hold-open functionality, allowing for faster reloads.

Caliber: 5.7x28mm
Capacity: 40rd
Finish: Black
Model: 5.7 AR Conversion Mag
Material: Metal
Model Fit: AR-15
Capacity: 40

Magazine Restrictions:

The following states have magazine restrictions. Your order will not ship to those states if in violation of these laws and will be subject to cancellation and a 15% restocking fee.

California - Limited to 10-round capacity.
Connecticut - Limited to 10-round capacity.
Colorado - Limited to a 15-round capacity.
Delaware - Limited to 17-round capacity.
Hawaii - Handguns limited to 10-round capacity
Illinois (Cook Co, Aurora, Highland Park) - Pistol mags are limited to 10 rounds.
Massachusetts - Limited to 10-round capacity.
Maryland - Limited to 10-round capacity.
New Jersey - Limited to 10-round capacity.
New York - Limited to 10-round capacity.
Road Island - Limited to 10-round capacity.
Vermont - Handguns limited to 15-round capacity, Rifles limited to 10-round capacity.
Washington DC - Limited to 10-round capacity.
Washington - Limited to 10-round capacity.