View source for M39A1 (20 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.''

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

* {{Specs-Link|f-100a_china}}
* {{Specs-Link|f-100d}}
* {{Specs-Link|f-100d_france}}

== 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).'' -->

* '''Default:''' {{Annotation|P|Practice}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|API-T|Armour-piercing incendiary tracer}}{{-}}{{Annotation|AP-I|Armour-piercing incendiary}}
* '''Universal:''' {{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|API-T|Armour-piercing incendiary tracer}}{{-}}{{Annotation|AP-I|Armour-piercing incendiary}}
* '''Air targets:''' {{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|API-T|Armour-piercing incendiary tracer}}{{-}}{{Annotation|AP-I|Armour-piercing incendiary}}
* '''Armored targets:''' {{Annotation|API-T|Armour-piercing incendiary tracer}}{{-}}{{Annotation|AP-I|Armour-piercing incendiary}}{{-}}{{Annotation|AP-I|Armour-piercing incendiary}}
* '''Stealth:''' {{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|AP-I|Armour-piercing incendiary}}

{| class="wikitable sortable" style="text-align:center" width="100%"
! colspan="10" | 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
|-
| P || P || 15 || 13 || 10 || 8 || 7 || 6
|-
| API-T || API-T || 40 || 36 || 22 || 12 || 6 || 3
|-
| AP-I || AP-I || 40 || 36 || 22 || 12 || 6 || 3
|-
| HEF-I || HEF-I || 2 || 2 || 2 || 2 || 2 || 2
|}
{| 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%
|-
| P || P || 1,030 || 0.1 || N/A || N/A || N/A || 47° || 56° || 65°
|-
| API-T || API-T || 1,030 || 0.1 || N/A || N/A || N/A || 47° || 60° || 65°
|-
| AP-I || AP-I || 1,030 || 0.1 || N/A || N/A || N/A || 47° || 56° || 65°
|-
| HEF-I || HEF-I || 1,030 || 0.1 || 0.2 || 0.1 || 16 || 79° || 80° || 81°
|-
|}

=== Comparison with analogues ===
''Give a comparative description of cannons/machine guns that have firepower equal to this weapon.''

== 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:'''

* High fire rate
* High velocity rounds
* Great penetration (53 mm maximum)

'''Cons:'''

* Low ammo count

== 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>.''

== 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 ==
''Paste links to sources and external resources, such as:''
* ''topic on the official game forum;''
* ''encyclopedia page on the weapon;''
* ''other literature.''

{{USA aircraft cannons}}
{{China aircraft cannons}}
{{France aircraft cannons}}

[[Category:Aircraft cannons]]