BX-1 10-round .22 LR caliber magazine is made of black plastic with steel feed and works with any factory original 10/22? Rifle SR-22? Rifle 22 Charger? Pistol and .22 LR Ruger American Rimfire? Rifle. Magazine will function in the .22 LR Ruger 77/22? 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.