Difference between revisions of "20 mm/70 Oerlikon Mk.II (20 mm)"

Latest revision as of 11:36, 21 November 2024

One of the two 20 mm/70 Oerlikon Mk.II on the stern of HMAS Nepal

Description

The 20 mm/70 Oerlikon Mk.II is a rapid-firing anti-aircraft cannon that played a crucial role in World War II and beyond. Developed by the Swiss company Oerlikon in the 1930s, this weapon system quickly gained popularity due to its high rate of fire, reliability, and versatility. It was widely used by the Allied forces during World War II and continued to serve in many navies around the world well into the 21st century.

Vehicles equipped with this weapon

Vehicles equipped with this weapon
SPAA	AEC AA · Crusader AA Mk II
Motor torpedo boats	PT-71 · PT-103 · PT-109 · PT-174 · PT-200 · PT-314 · Thunderbolt (PT-556) · PT-565 · PT-658
	MTB Vosper(2) · MTB-422
	MTB-96 · VTB-19 · VLT-2
	MS 444
Motor gun boats	Kim Qui · LCS(L)(3) · PTF-7 · USS Candid
	Fairmile B (ML345) · Fairmile C (332) · ML 1383 · SGB Grey Fox · SGB Grey Goose
	Asagao (YTE-01) · Alano
Armoured gun boats	LCM(6) Zippo
Gunboats	HMS Spey · La Suprise
Sub-chasers	SC-497 · PC-451 · Carmi (PC-466)
	HMCS Brantford · HMS Liscomb
Frigates	USS Hoquiam · USS Coolbaugh
Destroyers	USS Barker · USS Aylwin · USS Moffett · USS Phelps · USS Davis
	USS Fletcher · USS Bennion · USS Cowell · USS Sumner · USS Gearing · USS Frank Knox · USS Mitscher
	HMS Churchill · HMS Verdun · HMS Vega · ORP Garland · HMS Calpe · HMS Jervis · HMAS Nepal · HMS Eskimo
	La Combattante · Leopard · Le Malin · Le Triomphant
Light cruisers	USS Raleigh · USS Detroit · USS Helena · USS Cleveland · USS Roanoke
	HMS Enterprise · HMNZS Leander · HMS Arethusa · HMS Dido
	Duguay-Trouin · Jeanne d'Arc
Heavy cruisers	USS Portland · USS Baltimore
	HMS Hawkins · HMS London · HMS Norfolk · HMS York
Battlecruisers	USS Alaska
	HMS Repulse · HMS Renown
Battleships	USS Arkansas · USS Nevada · USS Tennessee · USS Texas
	Lorraine

General info

The 20 mm/70 Oerlikon Mk.II features a belt-fed mechanism that allows for rapid fire rates of up to 450 rounds per minute. Its lightweight and compact design made it ideal for use on various naval vessels, including destroyers, cruisers, and battleships. Its versatility also allowed it to be mounted on ground vehicles, making it a popular choice for anti-aircraft defence.

Available ammunition

Ground vehicles

Default: AP-T · HEF-I · AP-T
HET: HEFI-T · HEF-I · HEF-I
APT: AP-T

Penetration statistics
Ammunition	Penetration @ 0° Angle of Attack (mm)
Ammunition	10 m	100 m	500 m	1,000 m	1,500 m	2,000 m
HEF-I	4	4	3	3	3	3
AP-T	38	35	23	14	9	5
HEFI-T	4	4	3	3	3	3

Shell details
Ammunition	Velocity (m/s)	Projectile mass (kg)	Fuse delay (m)	Fuse sensitivity (mm)	Explosive mass (TNT equivalent) (g)	Ricochet
Ammunition	Velocity (m/s)	Projectile mass (kg)	Fuse delay (m)	Fuse sensitivity (mm)	Explosive mass (TNT equivalent) (g)	0%	50%	100%
HEF-I	838	0.12	0	0.1	6	-	-	-
AP-T	830	0.14	-	-	-	47°	60°	65°
HEFI-T	838	0.12	0.1	0.1	5	79°	80°	81°
HEF-I (HET)	838	0.12	0.1	0.1	5	79°	80°	81°

Naval vessels

Universal: HEF-T · HEF-I · AP-T
20 mm HE: HEF-T · HEF-I · AP-T · HEF-I
20 mm AP: AP-T · AP-T · AP-T · HEF-I

Penetration statistics
Ammunition	Penetration @ 0° Angle of Attack (mm)
Ammunition	10 m	100 m	500 m	1,000 m	1,500 m	2,000 m
HEF-T	2	2	2	2	2	2
AP-T	34	32	24	17	12	8
HEF-I	2	2	2	2	2	2

Shell details
Ammunition	Velocity (m/s)	Projectile mass (kg)	Fuse delay (m)	Fuse sensitivity (mm)	Explosive mass (TNT equivalent) (g)	Ricochet
Ammunition	Velocity (m/s)	Projectile mass (kg)	Fuse delay (m)	Fuse sensitivity (mm)	Explosive mass (TNT equivalent) (g)	0%	50%	100%
HEF-T	830	0.12	0	0.1	6.57	79°	80°	81°
AP-T	830	0.12	-	-	-	47°	60°	65°
HEF-I	830	0.12	0	0.1	11.17	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

Pros:

Fast rate of fire for a 20 mm.
Will destroy aircraft quickly, even if using armour-piercing rounds.

Cons:

Really poor penetration on the armour-piercing rounds for a 20 mm.

History

The story of the Oerlikon begins in World War I with German industrialist Reinhold Becker who developed the Becker Type 2 20 mm cannon which used an advanced primer ignition blowback action. It saw limited use during World War I, but at the end of the conflict, the Treaty of Versailles forbade further production or development in Germany resulting in the design being sold to the Swiss firm SEMAG in 1919. In 1924, SEMAG went bankrupt and the design and staff was bought out by another Swiss arms company, Oerlikon. In the build-up that preceded World War II, the British Admiralty tested the Oerlikon gun in 1934 but rejected it. In 1937, they recognized that they needed a light anti-aircraft gun for armed merchant cruisers and smaller warships. In 1938, they ordered for a new Oerlikon variant with a better rate of fire and that would be easy to service and maintain for auxiliary crews. The changes were make and resulted in the Oerlikon Mark I getting adopted by the Royal Navy with a production license. The Mark II came about in 1940 when the Fall of France led to them producing the design under license due to loss of access to Switzerland, but the location of the buffer springs was different and changes were made to make it suitable for mass production. The first ship to be commissioned with this model was the HMS Duke of York in November of 1941. About 55,000 guns were in service in the UK and Commonwealth navies by 1945. It was also used by the British on their attempt at an self-propelled anti-aircraft vehicle: the Crusader AA Mk II. However it didn't see much service due to the Luftwaffe (German Air Force) being almost non-existent by 1944.

This design also saw service in the United States Navy. The first two models were Model 1934s purchased for evaluation in 1937, but like with the Royal Navy, they were initially rejected. However, by 1940, the growing threat of the war led the Navy to reconsider and seek a one-to-one replacement for the AN-M2 Browning machine gun in the anti-aircraft. The Oerlikon thus entered widespread service by 1942 and would remain the main anti-aircraft gun of the US Navy until the introduction of the Bofors (40 mm) by late 1943. Loved by its crews for its ease of maintenance and high rate of fire, the Oerlikon Mark 2 in US service claimed 32% of all Japanese aircraft downed by the navy between the United States entry into the war in December 1941, to September of 1944. However, by September, the Japanese began engaging in kamikaze attack and the 20 mm Oerlikon was insufficient to stop these attacks leading to the Bofors being used to replace it. The Oerlikon remains in service today as a weapon for repelling boarders.

Media

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

External links

Paste links to sources and external resources, such as:

topic on the official game forum;
other literature.

Britain and USA anti-aircraft guns
7.92 mm	BESA
12.7 mm	M2HB
20 mm	GAI C01 · M168 · Oerlikon Mk.II · Polsten
25 mm	GAU-12U
30 mm	HSS 831L
35 mm	GA-35
37 mm	M1A2
40 mm	Bofors L/60 · Dual Automatic Gun M2 · M266
	Foreign:
23 mm	ZU-23 ^(USSR)
35 mm	Oerlikon KDA ^(Swiss)

USA naval cannons
20 mm	20 mm/70 Oerlikon Mk.II · 20 mm/70 Oerlikon Mark V · 20 mm/70 Oerlikon Mark 24
25 mm	25 mm/87 Mk.38
28 mm	1.1 inch/75 Mk.1
37 mm	AN-M4
40 mm	Bofors L/60 Mark 1 · Bofors L/60 Mark 2 · Bofors L/60 Mark 3
76 mm	3 inch/23 Mk.4 · 3-inch/50 Mk.10 · 3-inch/70 Mk.37 · 3-inch Mark 10 · 3 inch Mk.33 · 3-inch Mk.34
102 mm	4 inch/50 Mk.9
127 mm	5 inch/25 Mk.11 · 5 inch/25 Mk.13 AA · 5 inch/38 Mk.12 · 5-inch/50 Mk.5 · 5 inch/51 Mk.7 · 127 mm/54 Mark 18
152 mm	6 inch/47 Mk.16 · 6 inch/47 DP Mk.16 · 6 inch/53 Mk.12 · M81
203 mm	8 inch/55 Mark 9 · 8 inch/55 Mark 12 · 8 inch/55 Mark 14 · 8 inch/55 Mark 16
305 mm	12-inch/45 Mk.5 · 12 inch/50 Mk.7 · 12 inch/50 Mk.8
356 mm	14 inch/45 Mk.8 · 14 inch/45 Mk.12 · 14 inch/50 Mk.11

Britain naval cannons
20 mm	20 mm/70 Oerlikon Mk.II · 20 mm/70 Oerlikon Mark V · 20 mm/70 Oerlikon Mark 24
40 mm	2pdr QF Mk.IIc · 2pdr QF Mk.VIII · 2pdr Rolls Royce · QF Mark V · QF Mark VII · QF STAAG Mark II
47 mm	3 pdr QF Hotchkiss
57 mm	6pdr 7cwt QF Mk IIA · 6pdr QF Mk.V
76 mm	3 inch 12pdr 12 cwt QF Mk.V · 3 inch/70 Mark 6 · 76 mm/45 QF 3in 20cwt HA Mark I · 76 mm/50 12pdr 18cwt QF Mark I · OQF 3in 20cwt
102 mm	4 inch/40 QF mark III · 4 in QF Mark V · 4 inch/45 Mark XVI · 4 inch/50 BL Mark VII · BL Mark IX
114 mm	4.5 inch/45 QF Mark IV · 4.5 inch/45 QF Mark V · 8cwt QF Mk I
120 mm	4.7 inch/45 Mk.XII
133 mm	5.25 inch/50 QF Mark I
152 mm	6 inch/45 BL Mark VII · 6 inch/45 BL Mark XII · 6 inch/50 BL Mark XXIII · 6 inch/50 QF Mark N5
190 mm	7.5 inch/45 BL Mk.VI
203 mm	8 inch/50 Mark VIII
305 mm	305 mm/45 Mark X · 12 inch/50 Mark XI
343 mm	13.5 inch/45 Mark 5(H) · 13.5 inch/45 Mark 5(L)
381 mm	15 inch/42 BL Mark I
	Foreign:
20 mm	Rh202 ^(Germany)
40 mm	Bofors L/60 Mark 2 ^(USA) · Bofors L/60 Mark 3 ^(USA)
76 mm	3 inch Mk.33 ^(USA) · 76 mm/62 OTO-Melara Compact ^(Italy)

Japan naval cannons
20 mm	JM61 · Type 98
25 mm	25 mm/60 Type 96
37 mm	Type 4 · Type 11 pattern 1922
40 mm	40 mm/62 Vickers
57 mm	Type 97
75 mm	Type 88 AA
76 mm	3-inch/40 Type 41 · 8 cm/40 3rd Year Type · 8 cm/60 Type 98
100 mm	100/65 mm Type 98 mod A
120 mm	120 mm/45 3rd Year Type · 120 mm/45 10th year type
127 mm	5 inch/40 Type 89 · 127 mm/50 3rd Year Type
140 mm	140 mm/50 3rd Year Type
152 mm	6-inch/45 Type 41 · 15 cm/50 Type 41
155 mm	155 mm/60 3rd Year Type
200 mm	20 cm 3rd year type No.1
203 mm	20 cm/45 Type 41 · 20 cm/50 3rd year type No.2
356 mm	36 cm/45 Type 41
410 mm	410 mm/45 Type 3
	Foreign:
20 mm	20 mm/70 Oerlikon Mk.II ^{(USA/Britain)}
40 mm	Bofors L/60 Mark 1 ^(USA) · Bofors L/60 Mark 2 ^(USA) · Bofors L/60 Mark 3 ^(USA)
47 mm	3 pdr QF Hotchkiss ^(Britain)
76 mm	3-inch Mark 10 ^(USA) · 3 inch Mk.33 ^(USA) · 3-inch Mk.34 ^(USA)
120 mm	4,7-inch/40 Armstrong ^(Britain)
127 mm	5 inch/38 Mk.12 ^(USA)
305 mm	12-inch/45 Vickers ^(Britain) · 12-inch/50 Vickers ^(Britain)

Italy naval cannons
20 mm	20 mm/65 Breda · 20 mm/70 Oerlikon 3S · 20 mm/70 Scotti-Isotta Fraschini mod.1939
37 mm	37 mm/54 Breda Mod.32 · 37 mm/54 Breda Mod.38 · 37 mm/54 Breda Mod.39
40 mm	40 mm/39 Vickers-Terni mod.1915/1917 · 40 mm/39 Vickers-Terni mod.1915/1917, Modif.1930 · 40 mm/70 Breda-Bofors type 107
65 mm	65 mm/64 Ansaldo-Terni Mod.1939
76 mm	76 mm/40 Armstrong mod.1897/1910 · 76 mm/40 Armstrong mod.1897/1912 · 76 mm/40 Ansaldo mod.1917 · 76 mm/45 Schneider mod.1911 · 76 mm/50 Vickers mod.1909 · 76 mm/62 OTO-Melara Compact · 76-mm/62 SMP 3
90 mm	90 mm/50 Ansaldo model 1939
100 mm	100 mm/47 O.T.O. Mod. 1928 · 100 mm/47 O.T.O. Mod. 1937
120 mm	120 mm/45 Canet-Schneider-Armstrong mod.1918-19 · 120 mm/50 Armstrong model 1909 · 120 mm/45 O.T.O. Mod. 1926 · 120 mm/50 Ansaldo mod.1926 · 120 mm/50 O.T.O. Mod.1936
135 mm	135 mm/45 O.T.O. Mod. 1937
152 mm	152 mm/45 Schneider mod.1911 · 152/53 mm Ansaldo mod.1926 · 152/53 mm O.T.O. Mod.1929
203 mm	203 mm/50 Ansaldo mod.1924 · 203 mm/53 Ansaldo mod.1927
305 mm	305 mm/46 Armstrong model 1909 · 305 mm/46 Vickers model 1909
320 mm	320 mm/44 OTO model 1934 · 320 mm/44 Ansaldo model 1936
	Foreign:
20 mm	2 cm/65 Flakvierling 38 ^(Germany) · 20 mm/70 Oerlikon Mk.II ^(USA)
40 mm	Bofors L/60 Mark 1 ^(USA) · Bofors L/60 Mark 3 ^(USA)
76 mm	76 mm/50 Mk.33 ^(USA)
127 mm	127 mm/38 Mk.12 ^(USA)

France naval cannons
37 mm	37 mm/50 model 1925 · 37 mm/50 model 1933
47 mm	3 pdr QF Hotchkiss
57 mm	57 mm/60 ACAD Mle 1951
75 mm	75 mm/50 Canet model 1891 · 75 mm/50 model 1922
90 mm	90 mm/50 model 1926
130 mm	130 mm/40 model 1919
138.6 mm	138.6 mm/55 model 1910 · 138.6 mm/40 model 1927 · 138.6 mm/50 model 1929 · 138.6 mm/50 model 1934 R1938
152 mm	152 mm/55 model 1930
155 mm	155 mm/50 model 1920
203 mm	203 mm/50 model 1924
305 mm	305 mm/45 model 1906-10
340 mm	340 mm/45 model 1912
	Foreign:
20 mm	2 cm/65 C/38 ^(Germany) · 2 cm/65 Flakvierling 38 ^(Germany) · 20 mm/70 Oerlikon Mk.II ^{(USA/Britain)}
40 mm	2pdr QF Mk.IIc ^(Britain) · 2pdr QF Mk.VIII ^(Britain) · Bofors L/60 Mark 2 ^(USA) · Bofors L/60 Mark 3 ^(USA)
87.6 mm	Ordnance QF 25pdr (87.6 mm) ^(Britain)
102 mm	4 in QF Mark V ^(Britain) · 4 inch/45 Mark XVI ^(Britain)
105 mm	SK C/33 AA ^(Germany)
128 mm	12.8 cm/45 SK C/34 ^(Germany)
150 mm	15 cm/48 KC/36 ^(Germany)

@@ Line 1: / Line 1: @@
+[[File:20 mm 70 Oerlikon Mk.II (20 mm).jpg|thumb|x250px|One of the two 20 mm/70 Oerlikon Mk.II on the stern of [[HMAS Nepal]]]]
 == Description ==
-''Write an introduction to the article in 2-3 small paragraphs. Briefly tell about the history of the devekopment and combat using of the weaponry and also about it's features. Make a air or ground vehicles list on which this weapon is installed in our game.''
+<!-- ''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 '''20 mm/70 Oerlikon Mk.II''' is a rapid-firing anti-aircraft cannon that played a crucial role in World War II and beyond. Developed by the Swiss company Oerlikon in the 1930s, this weapon system quickly gained popularity due to its high rate of fire, reliability, and versatility. It was widely used by the Allied forces during World War II and continued to serve in many navies around the world well into the 21st century.
 === Vehicles equipped with this weapon ===
+<!-- ''List out vehicles that are equipped with the weapon.'' -->
+{{Navigation-Start|Vehicles equipped with this weapon}}
+{{Navigation-First-Line|'''SPAA'''}}{{Specs-Link|uk_armored_car_mk_2_aa}}{{-}}{{Specs-Link|uk_crusader_aa_mk_2}}
+{{Navigation-First-Line|'''Motor torpedo boats'''}}{{Specs-Link|us_higgins_78ft_pt71}}{{-}}{{Specs-Link|us_elco_80ft_pt_boat}}{{-}}{{Specs-Link|us_elco_80ft_pt109_boat}}{{-}}{{Specs-Link|us_elco_80ft_pt174}}{{-}}{{Specs-Link|us_higgins_78ft_pt625}}{{-}}{{Specs-Link|us_elco_80ft_pt_boat_mod01}}{{-}}{{Specs-Link|us_elco_80ft_pt_boat_thunderbolt}}{{-}}{{Specs-Link|us_elco_80ft_pt_boat_mod02}}{{-}}{{Specs-Link|us_higgins_78ft_pt658}}
+{{Navigation-Line| }}{{Specs-Link|uk_mtb_vosper_2series}}{{-}}{{Specs-Link|uk_higgins_78ft_mtb422}}
+{{Navigation-Line| }}{{Specs-Link|fr_mtb96_vosper}}{{-}}{{Specs-Link|fr_type40k_vedette}}{{-}}{{Specs-Link|fr_vlt2}}
+{{Navigation-Line| }}{{Specs-Link|it_ms444}}
+{{Navigation-Line|'''Motor gun boats'''}}{{Specs-Link|us_pgm_59_class}}{{-}}{{Specs-Link|us_lcs_l_3}}{{-}}{{Specs-Link|us_nasty_ptf}}{{-}}{{Specs-Link|us_admirable_class}}
+{{Navigation-Line| }}{{Specs-Link|uk_fairmile_b_ml345}}{{-}}{{Specs-Link|uk_fairmile_c_332}}{{-}}{{Specs-Link|uk_hdml_ml1383}}{{-}}{{Specs-Link|uk_sgb_304}}{{-}}{{Specs-Link|uk_sgb_309}}
+{{Navigation-Line| }}{{Specs-Link|jp_yuri_class_asagao}}{{-}}{{Specs-Link|it_alano_9851}}
+{{Navigation-Line|'''Armoured gun boats'''}}{{Specs-Link|us_lcm_zippo}}
+{{Navigation-Line|'''Gunboats'''}}{{Specs-Link|uk_frigate_river}}{{-}}{{Specs-Link|fr_frigate_croix_de_lorraine_class_la_surprise}}
+{{Navigation-Line|'''Sub-chasers'''}}{{Specs-Link|us_sc_497}}{{-}}{{Specs-Link|us_pc_451}}{{-}}{{Specs-Link|us_pc_466_carmi}}
+{{Navigation-Line| }}{{Specs-Link|uk_flower_class}}{{-}}{{Specs-Link|uk_isles_class_trawler}}
+{{Navigation-Line|'''Frigates'''}}{{Specs-Link|us_frigate_tacoma}}{{-}}{{Specs-Link|us_frigate_buckley_class_coolbaugh}}
+{{Navigation-First-Line|'''Destroyers'''}}{{Specs-Link|us_destroyer_clemson_barker}}{{-}}{{Specs-Link|us_destroyer_farragut_1942}}{{-}}{{Specs-Link|us_destroyer_porter_1942}}{{-}}{{Specs-Link|us_destroyer_porter_1944}}{{-}}{{Specs-Link|us_destroyer_somers_davis}}
+{{Navigation-Line| }}{{Specs-Link|us_destroyer_fletcher}}{{-}}{{Specs-Link|us_destroyer_fletcher_bennion}}{{-}}{{Specs-Link|us_destroyer_fletcher_cowell}}{{-}}{{Specs-Link|us_destroyer_sumner}}{{-}}{{Specs-Link|us_destroyer_gearing}}{{-}}{{Specs-Link|us_destroyer_gearing_frank_knox}}{{-}}{{Specs-Link|us_destroyer_mitscher}}
+{{Navigation-Line| }}{{Specs-Link|uk_destroyer_clemson_churchill}}{{-}}{{Specs-Link|uk_destroyer_v_class_verdun}}{{-}}{{Specs-Link|uk_destroyer_v_class_vega}}{{-}}{{Specs-Link|uk_destroyer_g_garland}}{{-}}{{Specs-Link|uk_destroyer_hunt_2series}}{{-}}{{Specs-Link|uk_destroyer_j_class}}{{-}}{{Specs-Link|uk_destroyer_n_class}}{{-}}{{Specs-Link|uk_destroyer_tribal}}
+{{Navigation-Line| }}{{Specs-Link|fr_destroyer_hunt_3series}}{{-}}{{Specs-Link|fr_destroyer_jaguar_class_leopard}}{{-}}{{Specs-Link|fr_destroyer_le_fantasque_class_le_malin}}{{-}}{{Specs-Link|fr_destroyer_le_fantasque_class_le_triomphant}}
+{{Navigation-Line|'''Light cruisers'''}}{{Specs-Link|us_cruiser_omaha_class_raleigh}}{{-}}{{Specs-Link|us_cruiser_omaha_class_detroit}}{{-}}{{Specs-Link|us_cruiser_brooklyn_class_helena}}{{-}}{{Specs-Link|us_cruiser_cleveland_class_cleveland}}{{-}}{{Specs-Link|us_cruiser_worcester_class_roanoke}}
+{{Navigation-Line| }}{{Specs-Link|uk_cruiser_enterprise_d52}}{{-}}{{Specs-Link|uk_cruiser_leander}}{{-}}{{Specs-Link|uk_cruiser_arethusa}}{{-}}{{Specs-Link|uk_cruiser_dido}}
+{{Navigation-Line| }}{{Specs-Link|fr_cruiser_dugauy_class_dugauy_trouin}}{{-}}{{Specs-Link|fr_cruiser_jeanne_darc}}
+{{Navigation-Line|'''Heavy cruisers'''}}{{Specs-Link|us_cruiser_portland_class}}{{-}}{{Specs-Link|us_cruiser_baltimore_class}}
+{{Navigation-Line| }}{{Specs-Link|uk_cruiser_hawkins}}{{-}}{{Specs-Link|uk_cruiser_london}}{{-}}{{Specs-Link|uk_cruiser_norfolk}}{{-}}{{Specs-Link|uk_cruiser_york}}
+{{Navigation-Line|'''Battlecruisers'''}}{{Specs-Link|us_battlecruiser_alaska_class}}
+{{Navigation-Line| }}{{Specs-Link|uk_battlecruiser_repulse}}{{-}}{{Specs-Link|uk_battlecruiser_renown}}
+{{Navigation-Line|'''Battleships'''}}{{Specs-Link|us_battleship_arkansas}}{{-}}{{Specs-Link|us_battleship_nevada}}{{-}}{{Specs-Link|us_battleship_tennessee}}{{-}}{{Specs-Link|us_battleship_texas}}
+{{Navigation-Line| }}{{Specs-Link|fr_battleship_bretagne_class_lorraine}}
+{{Navigation-End}}
 == General info ==
-''Tell us about the tactical and technical characteristics of the cannon or machine gun.''
+<!-- ''Tell us about the tactical and technical characteristics of the cannon or machine gun.'' -->
+The 20 mm/70 Oerlikon Mk.II features a belt-fed mechanism that allows for rapid fire rates of up to 450 rounds per minute. Its lightweight and compact design made it ideal for use on various naval vessels, including destroyers, cruisers, and battleships. Its versatility also allowed it to be mounted on ground vehicles, making it a popular choice for anti-aircraft defence.
+=== 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).'' -->
+; Ground vehicles
+* '''Default:''' {{Annotation|AP-T|Armour-piercing tracer}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|AP-T|Armour-piercing tracer}}
+* '''HET:''' {{Annotation|HEFI-T|High-explosive fragmentation incendiary tracer}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}
+* '''APT:''' {{Annotation|AP-T|Armour-piercing tracer}}
+{{:Oerlikon Mk.II (20 mm)/Ammunition|HEF-I, AP-T, HEFI-T, HET HEF-I}}
+; Naval vessels
+* '''Universal:''' {{Annotation|HEF-T|High-explosive fragmentation tracer}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|AP-T|Armour-piercing tracer}}
+* '''20 mm HE:''' {{Annotation|HEF-T|High-explosive fragmentation tracer}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}{{-}}{{Annotation|AP-T|Armour-piercing tracer}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}
+* '''20 mm AP:''' {{Annotation|AP-T|Armour-piercing tracer}}{{-}}{{Annotation|AP-T|Armour-piercing tracer}}{{-}}{{Annotation|AP-T|Armour-piercing tracer}}{{-}}{{Annotation|HEF-I|High-explosive fragmentation incendiary}}
-=== Available shells ===
+{{:{{PAGENAME}}/Ammunition|HEF-T, AP-T, HEF-I}}
-''Describe the shells that are available for the cannon and their features and purpose. If it iconcerns autocanons or machine guns, so write about different ammo belts and what is inside (which types of shells).''
 === Comparison with analogues ===
-''Give a comparative description of cannons/machine guns, that have firepower equal to these type of weapons.''
+''Give a comparative description of cannons/machine guns that have firepower equal to this weapon.''
-== Usage in the battles ==
+== Usage in battles ==
-''Describe the cannon/machine gun in the game - its distinctive features, tactics of usage against the main opponents. Please don't write a "guide" - do not impose a single point of view, but give the reader food for thought.''
+''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 ===
-''Summarize and briefly evaluate the weaponry in terms of its characteristics and combat effectiveness. Mark pros and cons as a list.''
+<!--''Summarise and briefly evaluate the weaponry in terms of its characteristics and combat effectiveness. Mark pros and cons as a list.''-->
 '''Pros:'''
-*
+* Fast rate of fire for a 20 mm.
+* Will destroy aircraft quickly, even if using armour-piercing rounds.
 '''Cons:'''
-*
-== Historical part ==
+* Really poor penetration on the armour-piercing rounds for a 20 mm.
-''Examine the history of the creation and combat usage of this weapon. If the historical reference turns out to be big one, take it into a separate article and add a link to it by using the "main" template. In the end be sure to include references to sources.''
+== 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>.'' -->
+The story of the Oerlikon begins in World War I with German industrialist Reinhold Becker who developed the Becker Type 2 20 mm cannon which used an advanced primer ignition blowback action. It saw limited use during World War I, but at the end of the conflict, the Treaty of Versailles forbade further production or development in Germany resulting in the design being sold to the Swiss firm SEMAG in 1919. In 1924, SEMAG went bankrupt and the design and staff was bought out by another Swiss arms company, Oerlikon. In the build-up that preceded World War II, the British Admiralty tested the Oerlikon gun in 1934 but rejected it. In 1937, they recognized that they needed a light anti-aircraft gun for armed merchant cruisers and smaller warships. In 1938, they ordered for a new Oerlikon variant with a better rate of fire and that would be easy to service and maintain for auxiliary crews. The changes were make and resulted in the Oerlikon Mark I getting adopted by the Royal Navy with a production license. The Mark II came about in 1940 when the Fall of France led to them producing the design under license due to loss of access to Switzerland, but the location of the buffer springs was different and changes were made to make it suitable for mass production. The first ship to be commissioned with this model was the HMS Duke of York in November of 1941. About 55,000 guns were in service in the UK and Commonwealth navies by 1945. It was also used by the British on their attempt at an self-propelled anti-aircraft vehicle: the [[Crusader AA Mk II]]. However it didn't see much service due to the Luftwaffe (German Air Force) being almost non-existent by 1944.
+This design also saw service in the United States Navy. The first two models were Model 1934s purchased for evaluation in 1937, but like with the Royal Navy, they were initially rejected. However, by 1940, the growing threat of the war led the Navy to reconsider and seek a one-to-one replacement for the [[AN-M2 (12.7 mm)|AN-M2 Browning]] machine gun in the anti-aircraft. The Oerlikon thus entered widespread service by 1942 and would remain the main anti-aircraft gun of the US Navy until the introduction of the [[Bofors (40 mm) (Family)|Bofors (40 mm)]] by late 1943. Loved by its crews for its ease of maintenance and high rate of fire, the Oerlikon Mark 2 in US service claimed 32% of all Japanese aircraft downed by the navy between the United States entry into the war in December 1941, to September of 1944. However, by September, the Japanese began engaging in kamikaze attack and the 20 mm Oerlikon was insufficient to stop these attacks leading to the Bofors being used to replace it. The Oerlikon remains in service today as a weapon for repelling boarders.
 == Media ==
-''An excellent addition to the article would be a video guide, as well as screenshots from the game and photos.''
+''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:''
-== Read 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.''
-''ETC.''
-== Sources ==
+== External links ==
 ''Paste links to sources and external resources, such as:''
-* ''topic on the official game forum''
-* ''page on the Wikipedia''
+* ''topic on the official game forum;''
-* ''page on aircraft or gorund forces encyclopedia''
+* ''other literature.''
-* ''other literature''
 {{Britain and USA anti-aircraft guns}}
+{{USA naval cannons}}
+{{Britain naval cannons}}
+{{Japan naval cannons}}
+{{Italy naval cannons}}
+{{France naval cannons}}
 [[Category:Anti-aircraft guns]]
+[[Category:Naval cannons]]

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