TEXT: 37mm M-6
  This is a cannon originally conceived after World War I as an antitank gun. It is now mainly found in the Twilight 2000 world on the
  M-8 Greyhound armored car in Third World nations.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  37mm M-6
  1
  395
  AP
  8
  6/5/4/2
  Nil
   
  1
  100
  APERS
  B25
  Nil
  Nil
   
  1
  295
  HE
  C2 B9
  -6C
  Nil
  57mm 6-Pounder
  This large caliber gun was designed as an antitank gun during the Second World War, and was the first to use discarding sabot
  ammunition. It was also known to the US and US allies as the 57mm M-1, and copied by the Russians.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  57mm 6-Pounder
  1
  390
  AP
  13
  16/14/12/6
  Nil
   
  1
  390
  APDS
  13
  27/24/20/19
  Nil
   
  1
  290
  HE
  C6 B8
  -2C
  Nil
   
  1
  390
  HVAP
  13
  21/18/15/8
  Nil
  Statistics by Aaron Woods.
  73mm Russian
  This is a large-caliber gun mounted on the BMP-1, BMD-1, BVP-1, Type 85, and WZ-551 infantry fighting vehicles. It ammunition
  is a modified version of the ammunition for the SPG-9 recoilless rifle.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  73mm Russian
  1
  250
  HE
  C4 B12
  6C
  Nil
   
  1
  250
  HEAT
  C1 B4
  48C
  Nil
  75mm French
  This is an older French gun derived from World War 2 tanks such as the Sherman, Grant, and Lee. It is mounted on some older
  French vehicles such as early versions of the AMX-13.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  75mm French
  1
  250
  APDS
  20
  64/56/48/32
  Nil
   
  1
  250
  APERS
  C8 B16
  3C
  Nil
   
  1
  250
  HE
  C4 B12
  5C
  Nil
  
   
  1
  250
  HEAT
  C2 B6
  51C
  Nil
   
  1
  250
  WP
  C1 B16
  2C
  Nil
  76.2mm 17-Pounder
  This weapon was designed as an antitank weapon during the Second World War. It is still found on some field pieces and some
  old Sherman tanks and other vehicles still in use by Third World countries.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  76.2mm 17-
  Pounder
  1
  430
  AP
  17
  28/24/20/11
  Nil
   
  1
  430
  APDS
  17
  48/41/34/19
  Nil
   
  1
  320
  HE
  C7 B20
  0C
  Nil
   
  1
  430
  HVAP
  17
  36/31/26/14
  Nil
  Statistics by Aaron Woods.
  76.2mm D56TM
  This is a Russian gun found on older tanks like the T-34 and light tanks like the PT-76. It is outmoded and outgunned by newer
  weapons, but is still used on these vehicles and on field pieces.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  D56TM
  1
  300
  APFSDS
  12
  40/35/30/20
  Nil
   
  1
  250
  HE
  C4 B12
  6C
  Nil
   
  1
  250
  HEAT
  C2 B8
  50C
  Nil
  76mm Cockerill
  This large-caliber gun is found on vehicles such as the Scorpion, Rooikat, and other light vehicles. It is useful against light armor,
  but cannot stand up against heavier vehicles, and is primarily useful as a support weapon.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  76mm Cockerill
  1
  300
  AP
  12
  40/35/30/20
  Nil
   
  1
  50
  APERS
  C8 B12
  4/3/2/-1
  Nil
   
  1
  300
  CHEM
  C3 (B20)
  Nil
  Nil
   
  1
  300
  HE
  C4 B12
  6C
  Nil
   
  1
  300
  HESH
  C10 B16
  42C
  Nil
  
  85mm Chinese
  This is a large-caliber gun used on field guns and vehicles such as the Type 63 and T-34/85. It is an improvement over the
  D56TM, but still no match for more modern weapons.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  85mm Chinese
  1
  275
  APHE
  C2 B4
  50C
  Nil
   
  1
  275
  HE
  C8 B12
  7C
  Nil
   
  1
  275
  HEAT
  C4 B8
  40C
  Nil
   
  1
  300
  HVAP
  22
  50/40/30
  Nil
  90mm French
  A large-caliber gun found on several French-made armored vehicles and some vehicles of other countries, such as Switzerland and
  Austria. The ammunition range is not as wide as that for the NATO 90mm gun.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  90mm French
  1
  300
  APFSDS
  22
  72/63/54/35
  Nil
   
  1
  300
  HE
  C4 B12
  6C
  Nil
   
  1
  300
  HEAT
  C4 B8
  65C
  Nil
  90mm NATO
  This gun is fitted to a wide variety of NATO vehicles and vehicles of many other countries worldwide. It has reasonable
  effectiveness except against tanks and can use a wide variety of ammunition types. This is a catch-all category including 90mm US
  and European-designed guns, including the British Cockerill 90mm guns.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  90mm NATO
  1
  300
  APC
  15
  45/37/32/21
  Nil
   
  1
  300
  APDS
  22
  58/50/43/28
  Nil
   
  1
  50
  APERS
  C8 B25
  3C
  Nil
   
  1
  300
  APFSDS
  22
  72/63/54/35
  Nil
   
  1
  250
  HE
  C4 B12
  6C
  Nil
   
  1
  250
  HEAT
  C4 B8
  65C
  Nil
   
  1
  225
  HEAT-Heavy
  C4 B8
  70C
  Nil
   
  1
  225
  HESH
  C10 B16
  60C
  Nil
   
  1
  250
  HVAP
  20
  63/52/46/30
  Nil
  
   
  1
  250
  WP
  C1 B12
  3C
  Nil
  100mm D-10
  This is an older Russian large caliber gun found on such tanks as the T-55 and Type 69, as well as field pieces, and a modified
  form is found on newer vehicles such as the BMP-3 and newer Pact T-55s. (This newer version can fire AT-10 ATGM through the
  gun barrel.) This gun has been much modified over the years in attempt to increase its effectiveness, and a wide variety of
  ammunition is available for it. Unlike most large-caliber tank guns, the D-10 may be used as an artillery piece, and has an indirect
  fire range.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  D-10
  1
  250
  AP
  16
  45/40/35/20
  21000
   
  1
  300
  APC
  13
  38/30/25/17
  21000
   
  1
  300
  APFSDS
  20
  60/50/35/30
  21000
   
  1
  250
  APHE
  C2 B4
  69C
  21000
   
  1
  250
  FRAG-HE
  C12 B16
  4C
  21000
   
  1
  250
  HE
  C8 B16
  9C
  21000
   
  1
  250
  HEAT
  C4 B8
  55C
  21000
   
  1
  275
  HVAPDS
  19
  57/50/42/28
  21000
  105mm NATO
  This was the standard US and Western tank main gun for almost 30 years before its replacement by the 120mm Rheinmetall. It is
  installed on a wide variety of tanks and armored vehicles, from the AMX-10RC to the M-1 tank. It has a large amount of different
  ammunition types available, in an attempt to keep it current.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  105mm NATO
  1
  500
  APFSDS
  26
  80/70/60/40
  Nil
   
  1
  500
  APFSDSDU
  26
  100/90/80/60
  Nil
   
  1
  500
  APFSDSDU M-900
  28
  110/100/90/70
  Nil
   
  1
  150
  Flechette
  B50
  1-Nil
  Nil
   
  1
  400
  HE
  C4 B18
  8C
  Nil
   
  1
  400
  HEAT
  C6 B12
  80C
  Nil
   
  1
  400
  HEAT M-815
  C10 B20
  110C
  Nil
   
  1
  875
  Israeli LAHAT
  C4 B8
  75C
  Nil
   
  1
  400
  WP
  C3 B20
  Nil
  Nil
  
  105mm L-7
  This is the British counterpart to the 105mm NATO gun. It is rifled, unlike the smoothbore barrel of the NATO gun, and offers
  superior range for the same sort of ammunition. Less variety is available, however.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  L-7
  1
  600
  APDS
  28
  65/55/50/30
  Nil
   
  1
  600
  APFSDS
  28
  80/70/60/40
  Nil
   
  1
  500
  HE
  C4 B18
  8C
  Nil
   
  1
  450
  HESH
  C10 B24
  57C
  Nil
  115mm U5TS
  This is the standard armament on the Russian T-62 tank, and some early models of the T-64. Its fin-stabilized rounds have a flat
  trajectory and reasonable accuracy. It's two-part rounds take longer to load than comparable NATO rounds.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  U5TS
  2
  400
  APFSDS
  22
  70/60/50/35
  Nil
   
  2
  400
  HE
  C12 B20
  9C
  Nil
   
  2
  300
  HEAT
  C4 B8
  65C
  Nil
  120mm Rheinmetall
  This German-designed gun is standard on most new US, NATO, and Western-aligned nations' tanks, as well as the Chinese Type
  89 antitank gun. Though its performance is superior to most tank guns, new ammunition has been devised over the years to keep
  up with current threats.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  120mm Rheinmetall
  1
  150
  APERS
  B75
  1-Nil
  Nil
   
  1
  500
  APFSDS
  28
  110/100/90/70
  Nil
   
  1
  500
  APFSDSDU
  28
  150/140/130/110
  Nil
   
  1
  550
  APFSDSDU M-829A3
  28
  170/160/150/110
  Nil
   
  1
  400
  HE
  C20 B40
  11C
  Nil
   
  1
  400
  HEAT
  C10 B20
  110C
  Nil
   
  1
  375
  HESH
  C14 B28
  100C
  Nil
   
  1
  750
  Israeli LAHAT
  C8 B16
  100C
  Nil
  
   
  1
  450
  MPAT
  C8 B16
  100C
  Nil
   
  1
  400
  STAFF
  C8 B16
  60C (T-A)
  Nil
   
  1
  875
  TERM-CE
  C8 B16
  100C (T-A)
  Nil
   
  1
  1000
  TERM-KE
  28
  130/120/110/100 (T-A)
  Nil
   
  1
  875
  TERM-TA STAFF FF
  C8 B16
  60C (T-A)
  Nil
   
  1
  400
  WP
  C3 B36
  Nil
  Nil
  120mm Rheinmetall L/55
  This is a longer barrel-length version of the standard 120mm Rheinmetall gun, found on the M-1A2P31, M-1A2 Giraffe, Leopard
  2A5, and some models of the Merkava 3. It has better range than its standard (L/44) counterpart.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  120mm L/55
  1
  175
  APERS
  B75
  1-Nil
  Nil
   
  1
  550
  APFSDS
  28
  110/100/90/70
  Nil
   
  1
  550
  APFSDSDU
  28
  150/140/130/110
  Nil
   
  1
  625
  APFSDSDU M-829A3
  28
  170/160/150/110
  Nil
   
  1
  450
  HE
  C20 B40
  11C
  Nil
   
  1
  450
  HEAT
  C10 B20
  110C
  Nil
   
  1
  425
  HESH
  C14 B28
  100C
  Nil
   
  1
  850
  Israeli LAHAT
  C8 B16
  100C
  Nil
   
  1
  500
  MPAT
  C8 B16
  100C
  Nil
   
  1
  450
  STAFF
  C8 B16
  60C (T-A)
  Nil
   
  1
  975
  TERM-CE
  C8 B16
  100C (T-A)
  Nil
   
  1
  1125
  TERM-KE
  28
  130/120/110/100 (T-A)
  Nil
   
  1
  975
  TERM-TA STAFF FF
  C8 B16
  60C (T-A)
  Nil
   
  1
  450
  WP
  C3 B36
  Nil
  Nil
  120mm L-11
  This is the British rifled gun counterpart to the 120mm Rheinmetall, in the same manner that the L-7 is the British counterpart to
  the 105mm NATO gun. The L-11 arms most British-made tanks; however, just before the Twilight War, these guns were being
  replaced by Rheinmetall guns to take advantage of the wider ammunition choices.
  
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  L-11
  1
  600
  APDS
  28
  90/75/65/50
  Nil
   
  1
  600
  APFSDS
  28
  110/100/90/70
  Nil
   
  1
  600
  APFSDSDU
  28
  150/140/130/110
  Nil
   
  1
  450
  HESH
  C14 B28
  100C
  Nil
  125mm Russian
  This gun arms most modern Russian tanks, since its introduction on the T-64. Updates have made it able to fire various ATGM
  through its gun barrel (such as the AT-8 and AT-11). This weapon is also mounted on a field carriage, known as the Rapira-3. The
  ATGM-firing versions were introduced because the 125mm Russian gun's long-range performance is not good. The autoloader for
  this gun on Russian tanks tends to grab the gunner's arm and attempt to load it into the gun barrel; on a catastrophic failure, the
  GM may rule that this has happened (causing 2d6 damage to the gunner's right arm, and requiring 6 phases to clear). This does
  not happen on the Rapira-3, since it does not have an autoloader.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  125mm Russian
  1
  450
  APFSDS
  28
  100/90/80/60
  Nil
   
  1
  450
  APFSDSDU
  28
  110/100/90/70
  Nil
   
  1
  400
  HE
  C14 B28
  11C
  Nil
   
  1
  400
  HEAT
  C10 B20
  110C
  Nil
  125mm Low-Pressure
  This is a gun found on the Russian 2S25 light airborne tank. It fires the same round as the 125mm Russian gun, but with a
  reduced powder charge to compensate for the lighter carriage on the vehicle. This affects range and hitting power.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  125mm Low-
  Pressure
  1
  350
  APFSDS
  25
  90/80/70/60
  Nil
   
  1
  350
  APFSDSDU
  25
  100/90/80/70
  Nil
   
  1
  350
  HE
  C14 B28
  11C
  Nil
   
  1
  350
  HEAT
  C10 B20
  110C
  Nil
  135mm Russian
  This Russian cannon is so far found only on the newest Russian tank, the T-95. It is a hard-hitting gun with better performance
  than the Russian 125mm, and it introduces a new fuel-air explosive round to the Russian arsenal, normally used against light
  vehicle columns.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  135mm Russian
  1
  500
  APFSDS
  30
  120/110/100/80
  Nil
  
   
  1
  500
  APFSDSDU
  30
  130/120/110/90
  Nil
   
  1
  500
  FAE
  C20 B36
  110/100/90/70
  Nil
   
  1
  400
  HE
  C16 B28
  12C
  Nil
   
  1
  400
  HEAT
  C12 B20
  120C
  Nil
  140mm NATO
  This is the next generation of Western tank guns, installed on such vehicles as the Leopard 2-140 and Merkava 4. Ammunition for
  this weapon was always scarce during the Twilight War, as so few vehicles used it, and little was made. However, its performance
  was rewarding.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  140mm NATO
  1
  700
  APFSDS
  31
  130/120/110/90
  Nil
   
  1
  700
  APFSDSDU
  31
  175/155/130/110
  Nil
   
  1
  550
  HE
  C26 B45
  13C
  Nil
   
  1
  550
  HEAT
  C13 B24
  130C
  Nil
   
  1
  550
  WP
  C4 B40
  Nil
  Nil
  142mm Demolition Gun
  This is a gun fitted to the French AMX-30 EBG combat engineer vehicle, used to destroy fortifications and obstacles. It has a
  secondary use of blowing mines in place. It fires only one type of round.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  142mm Demo Gun
  2
  125
  HESH
  C12 B20
  121C
  Nil
  152mm Gun/Missile Launcher
  This unusual weapon is found only on the Sheridan airborne combat vehicle (though in the 1960s and 1970s is was also found on
  the M-60A2 tank). It recoil is so violent for such a light tank that the firing of any conventional gun round (but not the Shillelagh
  missile) that there is a 2 in 10 chance on each firing that the rangefinder takes minor damage. This gun can also fire the Shillelagh
  ATGM through its gun tube (see US ATGMs).
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  152mm Gun/Missile
  1
  150
  APERS
  B75
  6C
  Nil
   
  1
  350
  HE
  C8 B32
  13C
  Nil
   
  1
  350
  HEAT
  C4 B16
  130C
  Nil
   
  1
  350
  WP
  C3 B36
  Nil
  Nil
  
  165mm Demolition Gun
  This is a gun mounted on the US M-728 and British Centurion AVRE combat engineer vehicles. It is the same concept as the
  French 142mm Demolition Gun listed above, but in a larger form.
  Weapon
  Reload
  Range
  Round
  Damage
  Penetration
  IFR
  165mm Demo Gun
  2
  125
  HESH
  C30 B36
  130C
  Nil
  
SOURCE: textdata/thevault/Twilight 2000/Unofficial/pmulcahy.com Archives/Large Caliber Guns/Twilight 2000 - Large-Caliber Guns.pdf