.577/450 Martini–Henry

Adopted in 1871 for the single-shot Martini-Henry rifle, this cartridge lengthened and bottlenecked the case of its predecessor, the .577 Snider, down to a .450 bullet. The name states two bore diameters rather than a caliber and charge: .577 for the parent case at its base, .450 for the bullet the necked-down case carries.

Its early service life was troubled by its own case construction rather than its ballistics. The first Marks were made from coiled brass sheet wrapped around a strengthening strip, a cheaper process than drawing a case from a single blank, and that construction proved fragile and prone to sticking in a fouled chamber. Reinforcement was increased through several Marks before the army abandoned the coiled case altogether in 1885 for a solid drawn-brass one, the construction every modern rifle cartridge now uses as a matter of course.

No dimensional standard governs an obsolete black-powder military round: the figures here are converted from the reference work Cartridges of the World rather than a primary standards body, so they carry estimated status throughout. No test-barrel length is published for the cartridge’s era ballistics, so only bullet mass is recorded for its load.