.56-56 Spencer

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 Model 1861 non-repeating breechloading rifles and carbines. It is a short-ranged cartridge, ineffective on anything larger than deer. Commercially loaded ammunition continued to be available into the 1920s and 1930s.

• Name —.56-56 Spencer • Origin — United States • Type — Rifle • Designer — Christopher Spencer • Case Type — Rimmed, straight • Bullet —.550 • Neck —.560 • Shoulder —.560 • Base —.560 • Rim Dia —.645 • Case Length —.875 • Length — 1.545 • Primer — Rimfire • Max Pressure — 11600 • Pressure Method — CIP • Bw1 — 350 • Vel1 — 1200 • En1 — 1125 • Balsrc — Barnes & Amber

The nomenclature of Spencer cartridges was unique. Unlike later cartridges such as 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. 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. All of these cartridges are rimfire primed. The actual bullet diameter of the.56-56 varied between.54 and.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 gr.512 in bullets. The.56-46 fired a 320 gr - 330 gr.465 in bullet. The Spencer rifle used a tubular magazine. To control the risk of accidental discharge owing to recoil, the.50 calibre round was reduced in calibre.