CMMG FourSix Mk4 AR-15 Magazine 4.6x30mm 40-Round Polymer Black

The CMMG FourSix Magazine is designed exclusively to feed the 4.6x30mm cartridge. Designed to seat into a standard AR15-sized magwell in order to feed the CMMG FourSix upper receiver along with either a CMMG Mk4, or other AR15 lower group of your choice. The 10 round capacity magazine features the same profile and size as the 40rd FourSix magazines and similar exterior dimensions to most 30rd 5.56mm AR15 magazines, but are limited to 10 rounds to remain complaint in restricted areas.