.401 Winchester Self-Loading

.401 Winchester Self-Loading
.401 Winchester Self-Loading (Center) with .308 Win (left) and .45-70 (right).
TypeRifle
Place of originUSA
Production history
DesignerWinchester Repeating Arms Company
Specifications
Case typeSemi-rimmed, straight
Bullet diameter.4065 in (10.33 mm)
Neck diameter.428 in (10.9 mm)
Base diameter.429 in (10.9 mm)
Rim diameter.457 in (11.6 mm)
Rim thickness0.05 in (1.3 mm)
Case length1.50 in (38 mm)
Overall length2.005 in (50.9 mm)
Rifling twist1 in 14 in (360 mm)
Primer typeLarge rifle
Maximum pressure37,000–39,000 psi (260–270 MPa)
Ballistic performance
Bullet mass/type Velocity Energy
200 gr (13 g) 2,141 ft/s (653 m/s) 2,037 ft⋅lbf (2,762 J)
250 gr (16 g) 1,875 ft/s (572 m/s) 1,952 ft⋅lbf (2,647 J)
Test barrel length: 20 inches (510 mm)
Source(s): Whelen, Townsend. The American Rifle. Century Co. 1918 p. 266

The .401 Winchester Self-Loading (.401SL / .401WSL) or 10.33x38mmSR is an American rifle cartridge.