Military Wiki
.45 Winchester Magnum
Wildey Cartridges.JPG
A lineup of Wildey cartridges, with the .45 Winchester second from left.
Type Pistol
Place of origin USA
Production history
Designer Winchester
Designed 1977
Manufacturer Winchester
Produced 1979
Parent cartridge None
Case type Rimless
Bullet diameter .452 in (11.5 mm)
Neck diameter .473 in (12.0 mm)
Base diameter .476 in (12.1 mm)
Rim diameter .480 in (12.2 mm)
Rim thickness .049 in (1.2 mm)
Case length 1.198 in (30.4 mm)
Overall length 1.575 in (40.0 mm)
Case capacity 38 gr H2O (2.5 cm3)
Primer type LP
Maximum CUP 40,000 CUP
Ballistic performance
Bullet weight/type Velocity Energy
230 gr (15 g) FMJ 1,400 ft/s (430 m/s) 1,001 ft·lbf (1,357 J)
260 gr (17 g) JSP 1,200 ft/s (370 m/s) 832 ft·lbf (1,128 J)
300 gr (19 g) RN 1,150 ft/s (350 m/s) 940 ft·lbf (1,270 J)

The .45 Winchester Magnum is a .45 caliber rimless cartridge intended for use in semi-automatic pistols. The cartridge is externally a lengthened .45 ACP with a thicker web to withstand higher operating pressures. The 45 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.[1]

The cartridge has been primarily used by hunters and metallic silhouette shooters.[2]


Although, the .45 Winchester Magnum may be based on the .45 ACP and have the same Rim and Base 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]).

General comments[]

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.[2]


  1. Dan Johnson (2009). "1911 Hot Rods". Intermedia Outdoors, Inc. Archived from the original on 2009-06-18. Retrieved 2011-11-21. 
  2. 2.0 2.1 Wahl, Paul (1980). "First Gas Operated Semi-Auto Pistol". p. 148. 

This page uses Creative Commons Licensed content from Wikipedia (view authors).