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 12autocannons. 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.[1]
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, 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, 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, high explosive incendiary, 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, 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, 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, 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.[2]
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.
110mm, also, known, 110mm, navy, 20mm, series, autocannon, cartridge, developed, navy, after, world, autocannons, they, called, series, they, range, from, typeautocannonplace, origin, usaservice, historyin, service1950s, presentused, byunited, states, navy, ro. 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 20 110mm USNTypeAutocannonPlace of origin USAService historyIn service1950s presentUsed byUnited States Navy Royal New Zealand Air ForceWarsVietnam WarProduction historyDesignerUnited States NavySpecificationsCase typeRimless bottleneckBullet diameter19 9 mm 0 78 in Neck diameter20 6 mm 0 81 in Base diameter29 mm 1 1 in Rim diameter29 5 mm 1 16 in Case length109 5 mm 4 31 in Overall length185 mm 7 3 in Primer typeElectricMaximum pressure600 MPa 87 000 psi Ballistic performanceBullet mass type Velocity Energy1 700 gr 110 g Mk 105 HEI 3 350 ft s 1 020 m s 21 494 ft lbf 29 142 J 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 1 Available loads EditSome of the available loads for the 20 110mm USN are as follows Name Pressure PSI Projectile weight grains Projectile Type Muzzle Velocity fps IdentificationCartridge 20 mm high pressure test 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 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 high explosive incendiary 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 letteringCartridge 20 mm high explosive incendiary Mk 106 Mod 0 amp 1 USN 60 000 1700 50 Impact detonating 3350 Unpainted fuze red and yellow projectileCartridge 20 mm armor piercing incendiary 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 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 2 References Edit 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 Layne Simpson ed Cartridges of the World 12th ed USA Gun Digest Books pp 512 513 Retrieved from https en wikipedia org w index php title 20 110mm USN amp oldid 1088051284, wikipedia, wiki, book, books, library,
