The Ruger Mark IV 22/45 Model 40190 is a .22 LR semi-automatic pistol combining Ruger's proven Mark IV design with a 4.40-inch threaded bull barrel, polymer 22/45 grip frame, and factory-installed Picatinny rail. With a 10+1 round capacity, adjustable rear sight, and 33.3-ounce weight, this configuration is built for dependable rimfire shooting and convenient customization.

A simple one-button takedown allows the barrel-receiver assembly to tilt up and separate from the grip frame without tools, providing convenient access for field-stripping and chamber-to-muzzle cleaning. The internal cylindrical bolt maintains consistent sight-to-barrel alignment, while the cold hammer-forged barrel features precise rifling designed for long-term durability and accuracy.

The 1/2"-28 threaded bull barrel comes with a thread protector, allowing the use of compatible muzzle accessories. A factory-installed Picatinny rail provides a mounting platform for compatible optics, while the fixed front sight and adjustable rear sight provide a traditional sighting option.

The comfortable precision-molded polymer grip frame features a serrated frontstrap and checkered backstrap, complemented by checkered 1911-style grip panels for a secure, non-slip hold. An ergonomic bolt stop, contoured ejection port, and easy-to-grasp bolt ears contribute to straightforward operation.

The ambidextrous manual safety can be converted to left-side-only operation with the included washer. A conveniently positioned push-button magazine release allows the magazine to drop free for convenient reloading. The pistol also incorporates a magazine disconnect designed to prevent discharge when the magazine has been removed.

The Ruger Mark IV 22/45 40190 includes two 10-round magazines, making it a versatile .22 LR platform for target shooting, training, recreational shooting, and range use.