| .458 HAM'R | |
| Origin: | United States |
| Designer: | Bill Wilson |
| Case Type: | Rebated, bottlenecked |
| Bullet: | .458 |
| Max Pressure: | 46,000 psi |
| Bw1: | 300 |
| Vel1: | 2100 |
| En1: | 2938 |
| Test Barrel Length: | 18 |
The .458 HAM'R (11.6x39mmRB) is a large bore, centerfire rifle cartridge, designed for use in AR-15 style rifles. Wilson Combat, owned by Bill Wilson (developer of .458 HAM'R), sells a .458 HAM'R chambered, AR-style firearm named the WC-12, which is between the sizes of the AR-10 and AR-15 platforms. AR-10 platforms with lowers that accept an AR-15 cartridge can also safely fire the .458 HAM'R.
It is very similar to the .458 SOCOM, specialized to operate at higher pressure, offering an increased range in a flatter trajectory. The cartridge uses an AR-15 sized magazine, but the cartridge pressures require a bolt, barrel, and receiver designed for the pressure of the AR-10 platform.
Bill Wilson of Wilson Combat designed the cartridge. The .458 HAM'R has a single sister cartridge under the HAM'R name, the .300 HAM'R, also designed by Wilson Combat.[1]