M...
Review confirmed by purchase 
The magazine is identical to the one that comes with the Glock 19X Coyote Umarex replica pistol. When the spring is fully compressed, the magazine holds 23 BBs. After loading the magazine with gas, you can shoot 4 magazines worth of BBs (about 85 rounds). Shots are effective until the blowback works and the BBs do not clearly lose muzzle velocity. Realistically, after firing 2 magazines (about 40 BBs), I refill the gas.
