20/577 Alexander Henry

The 20/577 Alexander Henry, also known as 20/577 Express, is an obsolete rifle cartridge.

20/577 Alexander Henry
TypeRifle
Place of originScotland
Production history
DesignerAlexander Henry
Designed1895
Produced1895
Specifications
Parent case20 bore
Case typeRimmed, bottleneck
Bullet diameter.584 in (14.8 mm)
Neck diameter.607 in (15.4 mm)
Shoulder diameter.674 in (17.1 mm)
Base diameter.706 in (17.9 mm)
Rim diameter.754 in (19.2 mm)
Rim thickness.06 in (1.5 mm)
Case length2.75 in (70 mm)
Overall length3.27 in (83 mm)
Ballistic performance
Bullet mass/type Velocity Energy
560 gr (36 g) UNK UNK
570 gr (37 g) 1,725 ft/s (526 m/s) 3,770 ft⋅lbf (5,110 J)
Source(s): The big game express[1] &
The Spanish Association of Cartridge Collectors[2]

Overview

The 20/577 Alexander Henry was developed and introduced by the Scottish gunmaker Alexander Henry around 1895 exclusively for his hunting rifles.[1][2][3][4][5]

The 20/577 Alexander Henry is a rimmed, bottlenecked centerfire rifle cartridge. The 20/577 Alexander Henry is derived from brass 20 bore cartridges necked down to accept a .584 in (14.8 mm) calibre bullet like the .577 Black Powder Express.[1][2][4][5]

The 20/577 Alexander Henry fired a 560 or 570 gr (36 or 37 g) lead, paper patched bullet driven by 6 drams (10.6 g) of blackpowder at 1,725 ft/s (526 m/s), its ballistic performance replicating that of the .577 Black Powder Express 3-inch. Later versions were loaded with mild loadings of cordite, carefully balanced through trial to replicate the ballistics of the blackpowder version, a copper-tubed lead bullet was also available, offering improved performance against dangerous game.[1][2][3][4][5]

See also

References
  1. Marrakai, "One of the harder ones: Alexander Henry's 20-bore/.577 Express", The big game express, No. 73, Eagle Park, Victoria: The Big Bore Rifle Club of Australia, July 2000.
  2. The Spanish Association of Cartridge Collectors, "20/577 Alexander Henry", municion.org, retrieved 17 July 2018.
  3. Cartridgecollector, "20/577 Black Powder Express", cartridgecollector.net, retrieved 17 July 2018.
  4. Cartridgecollector, "20/577 Alexander Henry Nitro for Black Powder", cartridgecollector.net, retrieved 17 July 2018.
  5. Czech Moravian Society of Collectors of Cartridges, "20/577 Alexander Henry", naboje.org, retrieved 17 July 2018.


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