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20×110mm USN
Cold War-era American autocannon cartridge
Cold War-era American autocannon cartridge
| Field | Value |
|---|---|
| name | **20×110mm USN** |
| origin | USA |
| type | Autocannon |
| service | 1950s–present |
| used_by | United States Navy |
| Royal New Zealand Air Force | |
| wars | Vietnam War |
| designer | United States Navy |
| is_SI_specs | yes |
| case_type | Rimless, bottleneck |
| bullet | 19.9 |
| neck | 20.6 |
| base | 29 |
| rim_dia | 29.5 |
| case_length | 109.5 |
| length | 185 |
| primer | Electric |
| max_pressure | 600 |
| is_SI_ballistics | no |
| bwunit | gr |
| bw1 | 1700 |
| btype1 | Mk 105 HEI |
| vel1 | 1010 |
| en1 | 56,105 j |
Royal New Zealand Air Force
The 20×110mm USN (also known as 20×110mm US Navy and 20mm Mk-100 Series) is an autocannon cartridge developed by the US Navy after World War II for use in Mk 11 and Mk 12 autocannons. They are called the Mk 100 series as they range from Mk 101 to Mk 109.
It has the same rim diameter as the 20×102mm but a different length and contour. It is not interchangeable with any other 20×110mm cartridge.
Available loads
Some of the available loads for the 20×110mm USN are as follows:
| Name | Pressure (PSI) | Projectile weight (grains) | Projectile Type | Muzzle Velocity (fps) | Identification |
|---|---|---|---|---|---|
| Cartridge, 20 mm, High Pressure Test (HPT), Mk 101 Mod 0 (USN) | Not to exceed 72,500 | 1700 | Inert | Not listed | Green or blue projectile with brown nose and 1/4 black letters reading "High pressure test round" |
| Cartridge, 20 mm, Low Pressure Test (LPT), Mk 102 Mod 0 (USN) | Not listed | 1700 | Inert | Not listed | Green or blue projectile with brown nose and 1/4 black letters reading "Low pressure test round" |
| Cartridge, 20 mm, Target Practice (TP), Mk 105 Mod 0 (USN) | Not to exceed 72,500 | 1700 | Inert | 3350 | Green or blue projectile black lettering or blue projectile with brown nose and black lettering |
| Cartridge, 20 mm, High Explosive Incendiary (HEI), Mk 106 Mod 0 & 1 (USN) | 60,000 | 1700 ±50 | Impact detonating | 3350 | Unpainted fuze, red and yellow projectile |
| Cartridge, 20 mm, Armor-Piercing Incendiary (API), Mk 107 Mod 0 (USN) | 60,000 | 1700 ±50 | Armor-piercing incendiary | 3350 | No fuze, nose of projectile blue or brown with red band. Body of projectile black with white lettering. |
| Cartridge, 20 mm, Armor-Piercing Tracer (AP-T), Mk 108 Mod 0 (USN) | 60,000 | 1700 ±50 | Armor-piercing tracer | 3350 | No fuze. Hollow windshield. Brown or yellow nose, body of projectile black with white lettering. |
There is also a cartridge, 20 mm, dummy, Mk 103 Mod 0 (USN) which is an inert round. It has an empty primer pocket and holes in the case or a plugged primer pocket. It may be empty or filled with inert material. The projectile is usually brass or bronze plated.
References
References
- Albert Watson III. (1985). "Small Calibre Ammunition Identification Guide, DST-1160G-514-82-VOL 2-CHG 1(Volume 2: 20mm to 40mm Cartridges.)". Defence Intelligence Agency.
- Frank Barnes. (2009). "[[Cartridges of the World]]". Gun Digest Books.
This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page.
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