(From Left to Right): A .577 Snider cartridge, a Zulu War-era rolled-brass-foil .577/450 Martini-Henry Cartridge,
a later drawn-brass .577/450 Martini-Henry cartridge, and a .303 British Mk VII SAA Ball cartridge.
Place of origin United Kingdom
Used by British Empire
Wars Anglo-Zulu War
Variants 11.43 x 60R (61R)
Parent case .577 Snider
Bullet diameter .455 in (11.6 mm)
Neck diameter .487 in (12.4 mm)
Shoulder diameter .628 in (16.0 mm)
Base diameter .668 in (17.0 mm)
Rim diameter .746 in (18.9 mm)
Rim thickness .06 in (1.5 mm)
Case length 2.34 in (59 mm)
Overall length 3.12 in (79 mm)
Bullet weight/type Velocity Energy
400 gr (26 g) lead 1,450 ft/s (440 m/s) 1,868 ft·lbf (2,533 J)
480 gr (31 g) lead 1,350 ft/s (410 m/s) 1,943 ft·lbf (2,634 J)
Source: Handbook for Shooters & Reloaders
Handloaders Manual of Cartridge Conversion
The .577/450 was based upon the same separate steel head used for the .577 Snider cartridge, with a wrapped foil body firing a nominally .45 calibre bullet, giving the cartridge a "bottle-necked" appearance. Initially, .577/450 cartridges were manufactured of rolled brass foil, but later on- shortly after the Anglo-Zulu War- it was discovered that the rolled foil cartridges were prone to jamming as the barrel heated up, and production was switched to the drawn brass style now commonly used for the manufacture of small arms ammunition.
The Martini-Henry single-shot lever action rifle had a Martini designed action married with the unique rifling designed by Alexander Henry. The first three patterns or "Marks" were equipped with a shorter lever, which was extended in the Mark IV pattern to address extraction problems in some climates. The Mark IV was the final and most refined form of the rifle in 577/450, but was already obsolete owing to the pending adoption of a smokeless powder small bore cartridge, which became the .303.
Most famously employed by British Forces during the Anglo-Zulu War of 1879- which included the Battle of Isandlwana and the Battle of Rorke's Drift- as well as during the Sudanese Campaign of 1884-1898, and in various other colonial conflicts in Africa and India, the .577/450 Martini-Henry cartridge was considered obsolete, though it was still in military production as late as World War I (for use by Royal Flying Corps observers and Zeppelin-buster aircrews), and in commercial production by Kynoch until the late 1950s.
Handloaders typically use .45-70 loading data for this cartridge, the load used by the military was 85 grains (5.5 g) of black powder with a 480-grain (31 g) bullet at 1,350 ft/s (410 m/s). 
* Cartridges of the World 4th Edition, Book by Frank C. Barnes, DBI Books p. 214
1. ^ a b c Ackley, P.O. (1979) . Handbook
for Shooters & Reloaders. vol II (8th Printing ed.). salt Lake City,
Utah: Plaza Publishing. p. 215. ASIN B000BGII48.