37mm M6

     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 M8 Greyhound armored car in Third World nations. 

40mm 2-Pounder

     Not to be confused with the 2-Pounder naval antiaircraft autocannon, the Ordnance QF 2-Pounder was on the verge of obsolescence even before it came into service in 1936, barely able to deal with the tanks of the time.  It was retained in service, to be used as an infantry support weapon, but was retired shortly after the end of World War 2.  In addition to a ground mount, it equipped several AFVs designed before or shortly after the start of World War 2, and despite its drawbacks, saw a significant amount of service.

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 M1, and copied by the Russians.

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.  Its ammunition is a modified version of the ammunition for the SPG-9 recoilless rifle.

75mm French/M1897A5

     This is an older French gun derived from before the turn of the 20^th century found on tanks such as the Sherman, Grant, and Lee.  It is also mounted on some older French vehicles such as early versions of the AMX-13.

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.  It’s long L/55 gun, firing a round with a greater propellant charge, gave it superior range and hitting power than comparable American designs of the time.

76mm L23A1

     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. The L23A1 is hampered by its very short L28.37 barrel, but the short barrel makes it ideal to mount on smaller vehicles.

76.2mm M1

     The M1 was purpose-designed for mounting on the Sherman, and was famous for its employment on the M4A3E8 “Easy Eight” variant of the M4 Sherman.  It was also the armament of late versions of the M10A1 tank destroyer.  The M1’s longer L/50 barrel gave it more velocity and hitting power than the M7.

76.2mm M7

     The M7 began life as a naval dual-purpose gun which became obsolete.  When the US Army began looking for a more powerful gun than the 75mm M1897A5, they chose the M1 Naval Gun because suddenly a lot of them were available, and then devised armor-piercing ammunition for it, calling the gun the M7. The M7 armed such tank destroyers as the M10 and M10A1.  The new ammunition was hampered by the short L/40 barrel length of the M7, and it was too large and heavy to put on the Sherman tank. It was supplanted in later tank destroyers and the Sherman tank by the M1 76.2mm tank gun.

76mm M32/M32A1/M32A2/M32K1

     The M32 series may be thought of as a 76mm gun taken to the OP level.  The M32 is a high-pressure 76mm gun, firing more powerful ammunition through a long L/60 barrel.  At the time of its introduction just after World War 2, guns were still needed for vehicles such as the M41 Walker Bulldog that were unable due to light chassis to mount the then-new 90mm guns. The M32 went through a number of iterations, improving the mounting hardware or lightening the gun or enabling it to fire even higher-pressure ammunition. The M32K1 is a Taiwanese variant of the M32A1; the APFSDS round for M32-series guns was designed specifically for use in the M32K1, but can also be used in other M32-series guns.

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.

85mm D-44

     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.

90mm CN90F3 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, but the gun is a reasonably modern smoothbore design with a long L/52 barrel.

90mm M3

     This gun played a role similar to the Nazi 88mm gun – it began life as a heavy AAA gun, then was adapted for use as an antitank gun, then made the leap to a vehicle-mounted gun, being mounted on the M36 tank destroyer and M26 Pershing tank, as well as the post World War 2 M56 Scorpion. The M3 used a long L/53 barrel for better muzzle velocity and range. Performance was comparable to the Tiger’s 88mm L/56 main gun, but fell short of the Tiger II’s L/71 main gun.  This led to the T30E16 HVAP shot, which was actually tungsten-cored (in today’s parlance, HVAPT). Continued improvements to the M3 led to the M41 below.

90mm M41 NATO/Cockerill

     This gun is fitted to a wide variety of NATO vehicles and vehicles of many other countries worldwide.  It has reasonable effectiveness except against some tanks and can use a wide variety of ammunition types. 

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.

105mm F2 BK MECA

     The 105mm F2 BK MECA was designed specifically for installation in the AMX-10RC wheeled cannon vehicle.  It was designed to be lighter and more compact than the corresponding NATO-standard gun, the 105mm L7/M68.  It is also a medium-pressure gun instead of the M68/L&’s high-pressure gun, and meant to produce less recoil than the L7/M68. It does not match the range of the L7/M68, and uses proprietary 105x527R ammunition, and cannot fire or even chamber NATO ammunition.

105mm M68/L7 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 M1 tank.  It has a large amount of different ammunition types available, in an attempt to keep it current.  The British L7 has a different breech, but is otherwise the same weapon.

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.  Its two-part rounds take longer to load than comparable NATO rounds.

NATO-Compatible 120mm Smoothbore Guns

L/44/48/50/52/55

     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.

120mm L11

     This is the British rifled gun counterpart to the 120mm Rheinmetall, in the same manner that the L7 is the British counterpart to the 105mm NATO gun.  The L11 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. 

120mm OTO Melara 120mm/45

     This gun was designed specifically for mounting on the B1 Centauro’s hull.  The unmodified version of this hull could not handle the recoil of the NATO 120mm L/44 gun.  The OTO Melara 120mm/45 is slightly longer than the NATO gun, but designed to operate at a lower pressure; it has superior damaging potential than the 105mm gun of the B1 Centauro, but less range than the NATO 120mm gun. The ammunition is the biggest part of this lower operating pressure, and is not compatible with the 120mm NATO gun or vice versa.  The only service use of this gun is on the Centauro 120mm used by Oman.

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.

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.

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. 

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.

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.

152mm Gun/Missile Launcher

     This unusual weapon is found only on the Sheridan airborne combat vehicle (though in the 1960s and 1970s it was also found on the M60A2 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).

165mm Demolition Gun

     This is a gun mounted on the US M728 and British Chieftain AVRE combat engineer vehicles.  It is the same concept as the French 142mm Demolition Gun listed above, but in a larger form.