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|.45 Winchester Mangum|
A lineup of Wildey cartridges, with the .45 Winchester second from left.
|Place of origin||USA|
|Bullet diameter||.452 in (Script error mm)|
|Neck diameter||.473 in (Script error mm)|
|Base diameter||.476 in (Script error mm)|
|Rim diameter||.480 in (Script error mm)|
|Rim thickness||.049 in (Script error mm)|
|Case length||1.198 in (Script error mm)|
|Overall length||1.575 in (Script error mm)|
|Case capacity||38 gr H2O (Script error cm3)|
|Maximum CUP||40,000 CUP|
|230 gr (Script error g) FMJ||1,400 ft/s (Script error m/s)||1,001 ft·lbf (Script error J)|
|260 gr (Script error g) JSP||1,200 ft/s (Script error m/s)||832 ft·lbf (Script error J)|
|300 gr (Script error g) RN||1,150 ft/s (Script error m/s)||940 ft·lbf (Script error J)|
The .45 Winchester Magnum, or simply .45 Magnum, is a .45 caliber rimless cartridge intended for use in semi-automatic pistols. The cartridge is a stretched version of the .45 ACP with additional strengthening in the web area to accommodate the higher operating pressure. The Win Mag is nearly identical in dimensions and loading to the .45 NAACO developed by the North American Arms Corporation for their Brigadier pistol, developed to supply to the Canadian Army after World War II. The army ultimately did not adopt the pistol and its non-NATO standard ammunition.
Although, the .45 Winchester Magnum may be based on the .45 ACP and have the same Rim and Base (web) dimensions, the .45 Winchester Magnum has no parent case. The .45 Winchester Magnum case is redrawn with thicker walls and longer case. The thicker wall dimensions of the .45 Winchester Magnum are designed to accommodate a higher internal pressure (40,000 cup) than that of the .45 ACP (18,000 cup [21,000psi or 140MPa]).
The .45 Winchester Magnum had been on the drawing board for two years before its introduction, in 1979, by Winchester. The cartridge did not gain much popularity due to the intermittent availability of the Wildey and LAR Grizzly pistols. The cartridge was chambered in the Thompson-Center Contender single shot pistols.
The cartridge provided the shooter with a higher performance level than the .44 Remington Magnum in a semiautomatic pistol. The cartridge is able to fire a heavier bullet than the .44 Magnum given similar velocities or similar weighted bullets at higher velocities.
The .45 Winchester Magnum gained a following among IHMSA competitors as it provided the power and performance necessary to knock down targets at an extended range. The cartridge has been used by handgun hunters and is among the few semi-automatic pistol (as opposed to revolver) cartridges which have been adopted for this sport.