Kel-Tec PMR-30

The Kel-Tec PMR-30 is a full-size semi-automatic pistol manufactured by Kel-Tec of the United States. It was made available in 2011. It has a single action trigger pull of and a manual safety device. It is chambered in .22 Winchester Magnum Rimfire and the special, factory-shipped, double-stack magazine has a capacity of 30 rounds. The PMR-30 uses fixed fiber optic open sights. The slide is also pre-drilled to allow for the mounting of various red-dot sights with the purchase of appropriate mounting plates from the manufacturer. It has a European-style magazine release.
Much polymer is used in the firearm to save on weight and cost, with a steel slide and barrel and aluminum internal grip frame.
Design.
Since its initial market introduction, the PMR-30 has undergone several improvements due to problems with the early available design. The twist rate on the barrel rifling was increased to 1:11 to better stabilize bullets and reduce key-holing. A stronger, lightly textured polymer is now used for the frame. This eliminates drooping of the frame that created a large gap previously seen between the front of the frame and the barrel. This also gives the frame a less shiny appearance, and a less slick feel in the hand. More metal was added as reinforcement at the breech to completely cover the rim of a loaded cartridge, presumably for increased user safety in the event of a cartridge case separation. Additional improvements to the newer design include screws that may be loosened to adjust the front sight for windage, and ".22 WMR" stamped on the slide.
Kel-Tec also offers an extended 5" threaded barrel for the PMR-30 with an aluminum flash-hider to reduce the high amount of muzzle flash produced by escaping gases.
Ballistics.
While a standard 40gr .22 Magnum (.22 WMR) round reaches velocities near 2,000 fps (600 m/s) at about 355 ft-lbs of energy (Energy = .5 * weight * velocity^2 / 7000 / 32.175) when fired from a rifle, the velocity and energy is significantly lower when fired from a handgun due to the shorter barrel. A standard 40gr .22 Magnum round fired from the PMR-30 is approximately equal in velocity and energy to a standard 40gr .22LR round fired from a rifle. At 1,200 ft/s (370 m/s), this is 127 ft-lbs of energy. Lighter bullets and various .22 Magnum ammunition with faster burning powder specifically manufactured for use in handguns can be expected to reach higher velocities and greater energies.