.56-56 Spencer

56-56 Spencer
Type	Rifle
Place of origin	USA
Production history
Designer	Christopher Spencer
Specifications
Bullet diameter	.550 in (14.0 mm)
Neck diameter	.560 in (14.2 mm)
Shoulder diameter	.560 in (14.2 mm)
Base diameter	.560 in (14.2 mm)
Rim diameter	.645 in (16.4 mm)
Case length	.875 in (22.2 mm)
Overall length	1.545 in (39.2 mm)
Ballistic performance
Bullet mass/type Velocity Energy 350 gr (23 g) 1,200 ft/s (370 m/s) 1,125 ft⋅lbf (1,525 J)
Source(s): Barnes & Amber

The 56-56 Spencer was an American rifle cartridge.

Designed for the Spencer rifle and carbine, patented 6 March 1860, it was employed by cavalry during the American Civil War, first appearing at Sharpsburg, and is credited with enabling Buford to hold off Lee's early attacks at Gettysburg.

The 56-56 was loaded with a slug of 350-360 gr (22.7-23.3 g) over 42-45 gr (2.7-2.9 g) of black powder. It was loaded by a variety of companies, and was also used in the Ballard and Joslyn carbines.

It is a short-ranged cartridge, ineffective on anything larger than deer. Commercially loaded ammunition continued to be available into the 1920s.

Nomenclature

The nomenclature of Spencer cartridges were unique. Unlike later cartridges like the .44-40 Winchester and .45-70, where the first number indicated caliber and the second the charge weight, the 56-56 refers solely to the case. The first 56 is the diameter of the case at the base .56 inches (14.2 mm), measured just past the rim, and the second 56 is the diameter at the case mouth, also 0.56 inches (14 mm). Later versions of the cartridge included the 56-52, 56-50, and 56-46, which had varying degrees of taper in the cases, to accommodate smaller diameter bullets. The cartridge designations typically appear without decimals, such as "56-56 Spencer"; the form ".56-56 Spencer", while common, is misleading.

The actual bullet diameter of the 56-56 varied between .54-.555 inches (13.7-14.1 mm), depending on ammunition manufacturer. The 56-52, made by Spencer, and the 56-50, made by Springfield, differed only in the degree of crimp, with the 56-50 having a greater crimp; both fired 350 grain .512-inch (13.0 mm) bullets. The 56-46 fired a 320 to 330 grain .465-inch (11.8 mm) bullet.

See also

• List of cartridges by caliber
• List of rifle cartridges
• Ballard carbine
• 13 mm caliber

References

• Barnes, Frank C., ed. by John T. Amber. "56-56 Spencer", in Cartridges of the World, pp.281-3. Northfield, IL: DBI Books, 1972. ISBN 0-695-80326-3.