VINTAGE RIFLES AND TWIST RATES

DOWN RANGE

- Mike Venturino

The last four decades of the nineteenth century were a time of great learning in regard to metallic cartridges and their rifles. Prior to that, most rifled barrels were not meant for bullets – as in elongated projectiles. Most civilian rifles were muzzleloaders shooting round balls, or in military usage, muzzleloading rifle-muskets that shot Minié balls. Those firearms were rifled with very slow rifling twists, often as slow as 1:72.

Nowadays, we speak of certain weights of bullets requiring certain rifling twists. An example is a box of Sierra .224-inch, 80-grain HPBTs stating on the label that barrels with 1:7 to 1:8 twists were needed. Actually, our modern method is slightly incorrect, as it is not the weight of the bullets that require certain rifling twists, but their lengths. In fact, in its 1870’s packaging of ammunition for Sharps rifles, the Union Metallic Cartridge Company included bullet length on its labels. For example, a 550-grain .45 bullet was 113⁄32 inches in length. A .44 bullet of 500 grains was 13⁄8 inches long.

After the U.S. Government adopted .50 Gov’t/.50-70 metallic cartridge firing rifles in 1866, the twist rate was tightened to 1:42. Although standard bullets for the .50-70 weighed 450 grains, they were only about an inch in length. It is written in the IDEAL HANDBOOK #28 (1927) and in CARTRIDGES OF THE WORLD 9th EDITION, that there were also .50-70 barrels with 1:24 twist rates. Lyman’s