View source for M256 (120 mm)

== Description ==
<!--''Write an introduction to the article in 2-3 small paragraphs. Briefly tell us about the history of the development and combat using the weaponry and also about its features. Compile a list of air, ground, or naval vehicles that feature this weapon system in the game.''-->
The '''120 mm M256''' is an American tank cannon used in its top rank vehicles. It is most famously used by the American M1 Abrams series of tanks since its installation in the [[M1A1 Abrams]] model, though it has saw usage in older American tanks like the [[M60 AMBT|M60]] main battle tank.

It is based off the [[Rh120 L/44 (120 mm)|Rheinmetall L/44 cannon]], though it is license-produced in America with a simplified design.

=== Vehicles equipped with this weapon ===
<!-- ''List out vehicles that are equipped with the weapon.'' -->

* {{Specs-Link|us_m60a3_slep}}
* {{Specs-Link|us_m1a1_abrams}}
* {{Specs-Link|us_m1a2_abrams}}

== General info ==
''Tell us about the tactical and technical characteristics of the cannon or machine gun.''

=== Available ammunition ===
<!-- ''Describe the shells that are available for the weapon and their features and purpose. If it concerns autocannons or machine guns, write about different ammo belts and what is inside (which types of shells).'' -->

'''American ammunition'''

{| class="wikitable sortable" style="text-align:center" width="100%"
! colspan="8" | Penetration statistics
|-
! rowspan="2" data-sort-type="text" | Ammunition
! rowspan="2" | Type of<br>warhead
! colspan="6" | Penetration @ 0° Angle of Attack (mm)
|-
! 10 m !! 100 m !! 500 m !! 1,000 m !! 1,500 m !! 2,000 m
|-
| M830 || HEATFS || 480 || 480 || 480 || 480 || 480 || 480
|-
| M830A1 || HEATFS || 350 || 350 || 350 || 350 || 350 || 350
|-
| M829 || APFSDS || 491 || 488 || 481 || 473 || 464 || 454
|-
| M829A1 || APFSDS || 598 || 596 || 589 || 580 || 570 || 560
|-
|}
{| class="wikitable sortable" style="text-align:center" width="100%"
! colspan="10" | Shell details
|-
! rowspan="2" data-sort-type="text" | Ammunition
! rowspan="2" | Type of<br>warhead
! rowspan="2" | Velocity<br>(m/s)
! rowspan="2" | Projectile<br>Mass (kg)
! rowspan="2" | Fuse delay<br>(m)
! rowspan="2" | Fuse sensitivity<br>(mm)
! rowspan="2" | Explosive Mass<br>(TNT equivalent) (g)
! colspan="3" | Ricochet
|-
! 0% !! 50% !! 100%
|-
| M830 || HEATFS || 1,140 || 13.1 || 0.05 || 0.1 || 2,360 || 65° || 72° || 77°
|-
| M830A1 || HEATFS || 1,410 || 11.4 || 0.05 || 0.1 || 1,390 || 65° || 72° || 77°
|-
| M829 || APFSDS || 1,670 || 3.94 || N/A || N/A || N/A || 78° || 80° || 81°
|-
| M829A1 || APFSDS || 1,569 || 4.64 || N/A || N/A || N/A || 78° || 80° || 81°
|-
|}

'''Export ammunition'''

{| class="wikitable sortable" style="text-align:center" width="100%"
! colspan="8" | Penetration statistics
|-
! rowspan="2" data-sort-type="text" | Ammunition
! rowspan="2" | Type of<br>warhead
! colspan="6" | Penetration @ 0° Angle of Attack (mm)
|-
! 10 m !! 100 m !! 500 m !! 1,000 m !! 1,500 m !! 2,000 m
|-
| KE-W || APFSDS || 583 || 579 || 569 || 556 || 542 || 528
|-
|}

{| class="wikitable sortable" style="text-align:center" width="100%"
! colspan="10" | Shell details
|-
! rowspan="2" data-sort-type="text" | Ammunition
! rowspan="2" | Type of<br>warhead
! rowspan="2" | Velocity<br>(m/s)
! rowspan="2" | Projectile<br>Mass (kg)
! rowspan="2" | Fuse delay<br>(m)
! rowspan="2" | Fuse sensitivity<br>(mm)
! rowspan="2" | Explosive Mass<br>(TNT equivalent) (g)
! colspan="3" | Ricochet
|-
! 0% !! 50% !! 100%
|-
| KE-W || APFSDS || 1,585 || 4 || N/A || N/A || N/A || 78° || 80° || 81°
|-
|}

=== Comparison with analogues ===
<!--''Give a comparative description of cannons/machine guns that have firepower equal to this weapon.''-->
* [[File:Germany_flag.png|25px|link=]] [[Rh120 L/44 (120 mm)]] - The original basis of the M256, the Rh120 L/44 matches many aspects of the American gun down to the reload rate. However, the M256 is vastly superior in APFSDS penetration performance due to the M829A1 round.
* [[File:Germany_flag.png|25px|link=]] [[Rh120 L/55 (120 mm)]] - An elongated version of the Rh120 L/44, the L/55 can exceed the M256 in APFSDS penetration and muzzle velocity values, but suffers in reload time.
* [[File:USSR_flag.png|25px|link=]] [[2A46M-5 (125 mm)]] - This Russian cannon is the only one in the tech tree able to come close to the M256 in APFSDS performance, but is still lacking and has a longer reload time than the M256. However, all of its chemical rounds are superior compared to the HEAT-FS the M256 can fire.
* [[File:Britain_flag.png|25px|link=]] [[L30A1 (120 mm)]] - This British cannon comes close to the M256 in terms of APFSDS penetrations alongside a slightly faster reload rate. However the only alternative chemical weapon is HESH, which means the gun must choose to focus in the armor-piercing capabilities of the APFSDS rounds or in the explosive powers of the HESH to do its damage.
* [[File:Japan_flag.png|25px|link=]] [[Type 90 L/44 (120 mm)]] - Another license-production version of the Rh120 L/44, this Japanese cannon is severely lacking compared to the M829A1 round fired by the M256. However, the gun's weapon platform in the Type 90 tanks have autoloaders to allow a way faster firing rate compared to Rh120 and M256 tanks.
* [[File:China_flag.png|25px|link=]] [[ZPT98 (125 mm)]] - Like the Russian 2A46M-5, though this Chinese cannon has a much better APFSDS round available at the cost of a longer reload and no gun-launched ATGM available.
* [[File:Italy_flag.png|25px|link=]] [[OTO Breda 120/44 (120 mm)]] - This Italian tank cannon fires the fastest and hardest-hitting APFSDS round out of a 120 mm L/44 cannon, despite having similar handling characteristics as the M256.
* [[File:France_flag.png|25px|link=]] [[GIAT CN120-26 F1 (120 mm)]] - This French tank cannon has slightly lower APFSDS performance than the M829A1 round, but has a reload rate of 6 seconds between round. Otherwise, performance are quite similar in terms of HEAT-FS performance.
* [[File:Sweden_flag.png|25px|link=]] [[Kan Strv 122 (120 mm)]] - See Rh120 L/44 entry due to near-identical performances.

== Usage in battles ==
''Describe the cannon/machine gun in the game - its distinctive features, tactics of usage against notable opponents. Please don't write a "guide" - do not impose a single point of view, but give the reader food for thought.''

=== Pros and cons ===
<!-- ''Summarise and briefly evaluate the weaponry in terms of its characteristics and combat effectiveness. Mark pros and cons as a list.'' -->

'''Pros:'''

* M829, KE-W (on the M60 AMBT), and M829A1 (on the M1A2 Abrams) are amongst the most powerful shells in the game, with M829A1 having the third highest penetration after the German DM53 and the Italian CL3143.
* The M256 on the M1A2 Abrams has access to the high velocity, proximity-fused M830A1 {{Annotation|HEAT-MP|High-explosive anti-tank multi-purpose}} shell, enabling the M1A2 to engage helicopters and low flying aircraft with devastating (and often hilarious) results. A direct hit isn't needed either due to the large amount of explosive filler and wide blast radius.
* Reload is comparable to other NATO MBTs - 7.8 seconds stock and 6 seconds with an aced crew.
* Relatively wide selection of shells - 1 APFSDS shell (M829) and 1 HEAT-FS shell (M830) on the M1A1, 2 APFSDS shells (M829 and M829A1), 1 standard HEAT-FS shell (M830) and 1 HEAT-MP shell (M830A1) on the M1A2 Abrams, the M60 AMBT gets access to the powerful KE-W APFSDS shell and the M830 HEAT-FS shell.
* M830A1 is the fastest HEAT based shell in the game with a muzzle velocity of 1,400 m/s.
* Extremely high muzzle velocity on M829, KE-W, and M829A1 makes longe range sniping a satisfying experience - M829 has the highest muzzle velocity out of the 3 APFSDS shells available.
* Great gun handling characteristics - the gun elevates towards +20 and depresses towards -10 very quickly.
* Very effective stabiliser - does not stop working at high speeds.

'''Cons:'''

* Poor stock grind - enemy tanks are very capable of withstanding M830 HEAT-FS.
* M830A1 is not effective against enemy MBTs - it only has 350 mm of chemical-based penetration.
* The M256 on the M1A1 Abrams and M60 AMBT do not get access to the M829A1 APFSDS shell and the M830A1 HEAT-MP shell.
* M830A1 needs to travel a certain distance to arm the fuse - unable to engage helicopters at close range, except for a direct hit.
* The reload isn't very impressive compared to contemporary tanks like the Leopard 2A5/6, the Strv 122, the Ariete and the Leclerc. The Type 90 and Challenger 2 beat it by a full second.
* M830A1 self-destructs at 4.5 kilometres - helicopters can engage the M1A2 way beyond that range.

== History ==
<!--''Examine the history of the creation and combat usage of the weapon in more detail than in the introduction. If the historical reference turns out to be too long, take it to a separate article, taking a link to the article about the weapon and adding a block "/History" (example: <nowiki>https://wiki.warthunder.com/(Weapon-name)/History</nowiki>) and add a link to it here using the <code>main</code> template. Be sure to reference text and sources by using <code><nowiki><ref></ref></nowiki></code>, as well as adding them at the end of the article with <code><nowiki><references /></nowiki></code>.''-->
In 1972, as the a replacement to the cancelled [[MBT-70]] and [[XM-803]] was beginning development by Chrysler and GM, a 120 mm smoothbore gun had been considered. However, the developing gun by West Germany was not expected to be produced in time to meet the scheduled production timeline, and so the [[M68 (105 mm)|105 mm M68]] was retained as the main armament for the upcoming design.<ref name="AbramsHunnicuttpg1">Hunnicutt 1990, p.163</ref> In 1976, during the decision on which company will receive the contract to produce the XM-1 tank, a separate decision was made for the tank to be able to accommodate a 120 mm gun in the future, either the British 120 mm rifled gun or the German smoothbore gun. On October 28th, the XM-1 designs were modified with this new requirement.<ref name="AbramsHunnicuttpg2">Hunnicutt 1990, p.190</ref> Chrysler eventually won the contract to produce the tanks, but they were armed with the [[M68A1 (105 mm)|105 mm M68A1]].

The German [[Rh120 L/44 (120 mm)|Rheinmetall 120 mm]] was eventually chosen to become the next tank armament for US tanks. Receiving a license to produce it, the Watervliet Arsenal produced the Rheinmetall cannon as the '''M256'''.<ref name="AbramsHunnicuttpg3">Hunnicutt 1990, p.224</ref> With the original Rheinmetall design considered overly complex and expensive, the M256 had been redesigned with fewer parts.<ref name="AbramsZalogapg1">Zaloga 1993, p.10</ref>

== Media ==
''Excellent additions to the article would be video guides, screenshots from the game, and photos.''

== See also ==
''Links to the articles on the War Thunder Wiki that you think will be useful for the reader, for example:''

* ''reference to the article about the variant of the cannon/machine gun;''
* ''references to approximate analogues by other nations and research trees.''

== External links ==
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* ''topic on the official game forum;''
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===References===
<references />

===Bibliography===

* Hunnicutt, R.P. ''Abrams: A History of the American Main Battle Tank.'' Presidio Press, 1990
* Zaloga, Steven. ''M1 Abrams Main Battle Tank 1982-1992.'' Osprey Publishing Ltd., 1993

{{USA tank cannons}}

[[Category:Tank cannons]]