Speer has introduced a .22 Winchester Magnum cartridge optimized for use in short barrel self-defense pistols. From a 1.9″ barrel the 40 grain bullet leaves the muzzle at 1150 fps, generating 99 ft/lbs of muzzle energy. It would likely perform better in longer barreled guns like the Kel-Tec PMR-30.
From comparison, the Speer Gold Dot Personal Protection .25 Auto is loaded with a 36 gr bullet which leaves a 2″ barrel at 900 fps with 63 ft/lbs of energy.
Speer says …
These loads are designed for compact rimfire handguns and specific self defense applications. A large cavity ensures maximum expansion and terminal ballistics at reduced velocities. Consistent 10 to 11-inch penetration was achieved in factory testing–in barrels as short as two inches.
“We wanted to design a self defense option that catered to the rimfire platform,” said Brand Director Rick Stoeckel. “We engineered these rounds for effective expansion and consistent functioning in close-quarter situations–where performance is absolutely critical.”