BX-1 10-round, .22 LR caliber magazine is made of black plastic with steel feed and works with any factory original 10/22A(R) Rifle, SR-22A(R) Rifle, 22 Charger(TM) Pistol and .22 LR Ruger American RimfireA(R) Rifle. Magazine will function in the .22 LR Ruger 77/22A(R) Rifle, but the contoured base does not match the profile on the bottom of this rifle; the JX-1 Rotary Magazine (#90057) is recommended for this rifle.