Ruger Mark IV 22/45 .22 LR 10-Round Factory Magazine

The factory Ruger 10-round magazine is the only mag a Mark IV 22/45 owner should run. Built from tough steel with a polymer follower and an oversized base plate that doubles as a reload-assist button, the factory 90599 magazine is the gold standard for reliability across the 22/45 platform. Aftermarket magazines exist (ProMag, etc.) but every long-term Mark IV thread on Rimfire Central and Ruger Forum recommends sticking with factory steel for serious shooting.

The 22/45 magazine is platform-specific. It fits the Mark IV 22/45, Mark IV 22/45 Lite, and Mark IV 22/45 Tactical — the polymer-framed 1911-grip-angle variants — but does NOT cross-fit the steel-frame standard Mark IV variants (Target, Hunter, Competition), which use the older Mark series magazine (Ruger P/N 90231). Always confirm which frame your pistol uses before ordering.

The single magazine sells for around $30 at Brownells, MidwayUSA, and ShopRuger. The two-pack (P/N 90646) is the better value for stocking deeper at around $44-50 for a pair. OpticsPlanet typically lists the single mag at $44.59 when in stock; supply is intermittent. The Mark IV burns through .22 LR faster than the typical centerfire pistol — a casual range trip routinely consumes 200-400 rounds — so a six-mag minimum stockpile is the realistic floor for a working 22/45 owner.