View source for MG 151 cannon

{{Infobox Weapon
|name= MG 151/15
|image= 
|caption= 
|origin={{flagcountry|Nazi Germany}}
|type= Aircraft Cannon
<!-- Type selection -->
|is_ranged= Yes
|is_bladed=
|is_explosive=
|is_artillery=
|is_vehicle=
|is_UK=
<!-- Service history -->
|service= 
|used_by=
|wars= World War II
<!-- Production history -->
|designer= 
|design_date=
|manufacturer= Waffenfabrik Mauser AG
|production_date=
|number= 
|variants= 
<!-- General specifications -->
|weight= 42.7 kg
|length= 
|part_length= 
|width=
|height=
|crew=
<!-- Ranged weapon specifications --> 
|cartridge= 15 x 96 mm cartridge
|caliber= 15 mm 
|action= 
|rate= 680 to 740 rpm
|velocity= 960 m/s
|range= 
|max_range= 
|feed= 
|sights= 
<!-- Artillery specifications -->
|breech=
|recoil=
|carriage=
|elevation=
|traverse=
<!-- Bladed weapon specifications --> 
|blade_type=
|hilt_type=
|sheath_type=
|head_type=
|haft_type=
<!-- Explosive specifications --> 
|diameter=
|filling=
|filling_weight=
|detonation=
|yield=
}}
{{Infobox Weapon
|name= MG 151/20
|image= 
|caption= 
|origin= Germany
|type= Aircraft Cannon
<!-- Type selection -->
|is_ranged= Yes
|is_bladed=
|is_explosive=
|is_artillery=
|is_vehicle=
|is_UK=
<!-- Service history -->
|service= 
|used_by=
|wars= World War II
<!-- Production history -->
|designer= 
|design_date=
|manufacturer= Waffenfabrik Mauser AG
|production_date=
|number= 
|variants= 
<!-- General specifications -->
|weight= 42 kg
|length= 
|part_length= 
|width=
|height=
|crew=
<!-- Ranged weapon specifications --> 
|cartridge= 20 x 82 mm cartridge
|caliber= 20 mm 
|action= 
|rate= 750 rpm
|velocity= 800 m/s
|range= 
|max_range= 
|feed= 
|sights= 
<!-- Artillery specifications -->
|breech=
|recoil=
|carriage=
|elevation=
|traverse=
<!-- Bladed weapon specifications --> 
|blade_type=
|hilt_type=
|sheath_type=
|head_type=
|haft_type=
<!-- Explosive specifications --> 
|diameter=
|filling=
|filling_weight=
|detonation=
|yield=
}}

The '''MG 151 (MG 151/15)''' was a '''15&nbsp;mm''' [[autocannon]] produced by [[Waffenfabrik Mauser]] starting in 1940. It was in 1941 developed into the '''20&nbsp;mm MG 151/20''' cannon which was widely used on many types of [[Germany|German]] ''[[Luftwaffe]]'' fighters, fighter bombers, night fighters, ground attack and even bombers as part of or as their main armament during [[World War II]].
 
==History (MG 151/20)==
The 15&nbsp;mm MG 151 was found to have lackluster performance as the main gun on [[Messerschmitt Bf 109]] early F-2, and was soon replaced by the 20&nbsp;mm version to become the standard cannon for the Bf 109F-4 series onwards until it was superseded by the 30&nbsp;mm [[MK 108 cannon]].<ref>[http://www.vectorsite.net/avbf109_2.html Second Generation Bf-109s / Unusual Variants]. Retrieved on 2009-06-05.</ref>

To create the MG 151/20 round, Mauser simply necked out the MG 151/15's case (i.e. enlarged the opening of the case where the shell fits in) to fit a 20&nbsp;mm shell — which, incidentally, was the same shell used in the [[MG FF cannon]] — and shortened the length of the case so that the total length of the complete round was the same for both calibres. These measures simplified conversion of the cannon between calibres, so that it was possible to convert the 15&nbsp;mm to the 20&nbsp;mm MG 151/20 simply by changing the barrel and making other small modifications. However, this simple modification-based approach was not without its drawbacks. The relatively short case of the 20&nbsp;mm round, coupled with the larger and heavier 20&nbsp;mm projectile cost some [[muzzle velocity]] (950 m/s for the 15&nbsp;mm round vs. 800 m/s for the 20&nbsp;mm round - a 16% drop). {{Fact|date=February 2007}} However, in comparison to the earlier [[MG FF cannon]], the MG&nbsp;151 had a higher muzzle velocity which gave it a more predictable trajectory and higher impact velocity/longer range.

Nevertheless, the extra [[high explosive|HE]] capacity was considered well worth the loss in muzzle velocity. The basic 20&nbsp;mm HE round, for example, had almost 30% more explosive content by weight than the 15&nbsp;mm shell. Furthermore, the MG 151/20 also used the ''[[Minengeschoß]]'' ("mine shell"), which was made using drawn steel (similar to making cartridge cases) instead of being cast, as was typically done to make cannon shells at the time. The result was a shell with very thin yet strong walls, and hence a very large explosive (or [[Incendiary ammunition|incendiary]]) capacity. Indeed, the 20&nbsp;mm M-shell carried 6-8 times the amount of explosives contained in the 15&nbsp;mm shell.

The new 20&nbsp;mm shell was relatively effective against enemy aircraft, with the possible exception of heavily-built U.S. bombers such as the [[B-17 Flying Fortress]]. German statistics data showed that on average the 151/20 required an average of 25 hits to down a B-17, while 18-20 hits were required to down other 4-engine bomber types, and only four hits were required to down a single-engine fighter. While the larger round rapidly replaced its predecessor - the MG 151/15 was phased out in [[1942]] - German engineers continued research into an even heavier cannon that could rapidly demolish heavy enemy bombers.

Eight hundred MG 151/20 were exported to Japan by a submarine in August 1943 and were used to equip 388 [[Imperial Japanese Army Air Force|Japanese]] [[Kawasaki Ki-61|Ki-61-I Hei]] fighters.<ref>[http://www.markkaiser.com/japaneseaviation/hien.html Ki-61 survey]. Retrieved on 2009-06-04.</ref>

===Postwar Use===
After WWII, numbers of ex-Luftwaffe MG 151/20 cannon were removed from inventory and from scrapped aircraft and used by various nations in their own aircraft. The [[French Air Force]] and [[French Army Light Aviation|French Army aviation arm]] (ALAT) utilized MG 151/20 cannon as both fixed and flexible armament in various aircraft, including helicopters. The FAF and ALAT jointly developed a rubber-insulated flexible mount for the MG 151/20 for use as a flexible door gun, which was later used in combat in Algeria aboard several FAF/ALAT [[Piasecki H-21|H-21C]] assault transport helicopters.

The 15mm caliber is similar to a 14.5mm round, developed in World War 2 for the Soviet PTRD and PTRS antitank rifles and used in post-war heavy machine guns.  Recent developments of 14.5mm High Explosive Incendiary rounds may be regarded as a revival of the 15mm cannon concept. 

__NOTOC__

== MG 151 specifications ==
* Type: single-barrel automatic cannon
* Caliber: 15&nbsp;mm x 96 
* Operation: [[Recoil operation|Recoil-operated]]; [[short recoil]]
* Length: 1916&nbsp;mm
* Barrel length: 1254&nbsp;mm
* Rifling: 8 grooves, right hand twist, 1 turn in 16"
* Weight (complete): 38.1&nbsp;kg (84 lb)
* Rate of fire: 740 rpm
* Effective range: 400 m
* Muzzle velocity: 960 m/s (HE-T, HEI-T); 850 m/s (AP-T); 1030 m/s AP(WC)
* Projectile types:
** AP-T weighting 72 g
** AP(WC) weighting 52 g
** HE weighting 57 g. HE filler: 2.8 g

== MG 151/20 specifications ==
Two versions of the 20&nbsp;mm MG 151 were built: one with a percussion priming system and a second E-model with electrical priming. Some rounds were available with a timer self destruct and/or tracer (or glowtracer). There were also different types of high explosive shell fillings with either standard [[PETN]], a mixture called HA41 ([[RDX]] and [[aluminium]]), and a compressed version where more explosives were compressed into same space using large pressures (XM).

* Type: single-barrel automatic cannon
* Caliber: 20&nbsp;mm x 82 
* Operation: [[Recoil operation|Recoil-operated]]; [[short recoil]]
* Length: 1766&nbsp;mm
* Barrel length: 1104&nbsp;mm
* Rifling: 1 turn in 23
* Weight (complete): 42.7&nbsp;kg
* Rate of fire: 750 rpm
* Effective range:
* Muzzle velocity: 805 m/s (M-Geschoss); 705 m/s (HE-T, AP)
* Round types:

==Ammunition specifications==
        
{| border="1" width="100%"
|-----
! <font size="-2">German Designation</font>
! <font size="-2">US Abbreviation</font>
! <font size="-2">Projectile Weight [g]</font>
! <font size="-2">Bursting charge [g]</font>
! <font size="-2">Muzzle Velocity [m/s]</font>
! <font size="-2">Description</font>
|-----
| Brandsprenggranatpatrone 151 mit L'spur ohne Zerleger || HEI-T || align="center" | 113 
| align="center" | 2.3 g HE (nitropenta) + <br>2.1 g incendiary (elektron)
| align="center" | 705 || Nose fuze, tracer, no self-destruct
|-----
| Brandgranatpatrone 151  || incendiary || align="center" | 117 
| align="center" | 6.6 to 7.3 g incendiary (BaNO<sub>3</sub>+Al+Mg)
| align="center" | ? || Nose fuze
|-----
| Minengeschosspatrone 151 ohne L'Spur || HE || align="center" | 95
| align="center" | 18.6 g HE (nitropenta)
| align="center" | 805 || Nose fuze, no tracer
|-----
| Panzergranatpatrone 151 mit L'spur ohne Zerleger || AP-T || align="center" | 117 
| align="center" | none (bakelite filling in cavity)
| align="center" | 705 || No fuze, tracer, no self-destruct.<br>Penetration 13mm steel at 60 degree impact, 100m range.
|-----
| Panzersprenggranatpatrone 151  || APHE || align="center" | 115 
| align="center" | 4 g HE (nitropenta)
| align="center" | ? || Detonation after 5mm steel penetration.
|-----
| Panzerbrandgranatpatrone (Phosphor) 151 ohne Zerleger || API || align="center" | 115 
| align="center" | 3.6 g incendiary (WP)
| align="center" | 720 || No fuze, no self-destruct.<br>Penetration 3 to 15mm of steel.
|-----
| Panzerbrandgranatpatrone (Elektron) 151 ohne Zerleger || API || align="center" | 117 
| align="center" | 6.2 g incendiary (Elektron)
| align="center" | 695 || Optimized for strafing unarmoured ships. No self-destruct. Penetration 15 mm of steel at 75 degree impact angle, 100 m range.<br>Fuze functions after 4 mm steel penetration.
|}

==See also==
*[[List of weapons of military aircraft of Germany during World War Two|WW2 Luftwaffe aircraft weapons]]
*[[MK 108 cannon|Mk 108 30 mm cannon]]

==References==
{{Reflist}}

==External links==
* [http://www.lonesentry.com/articles/ttt/mg151-aircraft-weapon-ww2.html WWII era US Military report on the weapons]
* [http://www.wehrtechnikmuseum.de/Exponate/Artillerie/k-020MG151Dr.JPG External Image]
* [http://www.prinzeugen.com/Weapons.htm Prinz Eugen site containing information]
* [http://books.google.com/books?id=hdQBTcscxyQC&printsec=frontcover&dq=Aircrafts+of+the+Luftwaffe&ei=MaChS7X1BIqCyATijfTMBA&cd=1&hl=en#v=onepage&q=&f=false Aircraft of the Luftwaffe - Gun placements]
{{Aviation lists}}

[[Category:Automatic cannons]]
[[Category:Aircraft guns]]

[[Category:2Fix]]