Johnson based the cartridge on the .348 Winchester in order to create a rifle capable of handling the large bears in Alaska.

Harold Johnson necked out the .348 Winchester case to accept a .510" diameter bullet,[2] and Harold Fuller developed the barrel, marrying a .50 caliber barrel to an old Winchester Model 1886 rifle.

It didn't take Johnson long to find out that the truncated-shaped "solid" would shoot through a big brown bear from any direction, claiming in 1988, "I never recovered a slug from a bear or moose, no matter what angle the animal was shot at.

"[citation needed] Harold's favorite load in the .50 Alaskan was 51.5 grains (3.34 g) of IMR-4198 with a Barnes 400-grain (26 g) flatnose, jacketed bullet for about 2,100 ft/s (640 m/s) and just under 4,000 ft⋅lbf (5,400 J) of muzzle energy.

[8] Although it is considered a wildcat cartridge, loaded ammunition is available from Buffalo Bore.