Patent ID: 8887428

Claim:
A variable capacity modular firearm magazine, comprising: a butt plate having a front wall, a pair of opposing side walls, and a spring retention cavity disposed along a bottom wall; one or more rigid modular bodies, each including an elongated hollow tubular shape having a front side wall, a back side wall and a pair of opposing side walls defining an open top end and an open bottom end, each of said one or more rigid modular bodies further including a pair of flanges extending outward along a bottom end of each of the opposing side walls, said flanges being separated by a first distance, and further including an elongated channel that is disposed along an upper end of each of the front wall and the opposing side walls, said channel including a pair of nubs that are disposed within the channels at a complementary location to the first distance, wherein each of the flanges and channels include a complementary shape and dimension; a receiver member that includes a rigid elongated hollow tubular shape having a front side wall, a back side wall and a pair of opposing side walls defining an open top end and an open bottom end; and a cartridge engagement unit that includes at least one spring and a follower, said unit having a size and shape that are configured to operate within each of the receiver member and the one or more modular bodies, wherein each of the butt plate and the receiver member further include at least one fastener.