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MG FF/M:
The MG FF/M was a motor cannon with 20 mm caliber. This gun was manufactured in Germany under licence, but it was developed by Oerlikon in Switzerland. The MG FF/M was 1338 mm long at a weight of 26,3 kg. The cadence of this weapon was 540 rounds per minute at max, the speed, the projectiles got, leaving the muzzle was 700 meters per second.
The cartridge had a weight of 202 g, 134 g apportioned to the projectile. The ammunition was stored in magazines.
Deployed by the Luftwaffe in 1935 it soon became obsolete, because the penetration was not enough to destroy the heavy allied bombers anymore. The MG FF/M often got jammed or the shells broke, what didn´t make this weapon very reliable.
The MG FF was mounted in nearly the whole "Bf 109 E" family, the "Bf 109 D" and the "Bf 109 F-0" and "F-1". It was als well used as wing armament, as also as motor gun.
Incidentally, I believe that the 60-round drum was normally only loaded with 55 rounds as it was more reliable that way.
The point of showing the 20mm was not adequate is a specific situation shows the complexity of comparing any weapon system. In this case at short range an incoming radial engine fighter (or light bomber) could not be stopped with 20mm in time. Hence there are limits to the 20mm effectiveness. The fact they moved from .50 cal to 20mm to 40mm does not change the discussion about fighter air to air armament effectiveness. It does show that even quad 20mm cannot stop a fighter quickly enough to protect a ship.
The point is that the fighter with 4 x 20mm will do a lot more damage, faster than a fighter with 6 x 0.5 mg. This can easily make the difference between the attacker reaching the target or not. There is a reason why the F6F5 could have been been armed with 2 x 20 and 4 x 0.5 had the US 20mm been reliable.The point of showing the 20mm was not adequate is a specific situation shows the complexity of comparing any weapon system. In this case at short range an incoming radial engine fighter (or light bomber) could not be stopped with 20mm in time. Hence there are limits to the 20mm effectiveness. The fact they moved from .50 cal to 20mm to 40mm does not change the discussion about fighter air to air armament effectiveness. It does show that even quad 20mm cannot stop a fighter quickly enough to protect a ship.
But that was not my comment. It is that the 6 or 8 .50 were good enough for the day, and did not see a need to switch to 4x20mm. In WWII the US did not have production capability of either 20mm guns or ammo. They could produce massive amounts of .50 guns and ammo.The point is that the fighter with 4 x 20mm will do a lot more damage, faster than a fighter with 6 x 0.5 mg.
But that was not my comment. It is that the 6 or 8 .50 were good enough for the day, and did not see a need to switch to 4x20mm. In WWII the US did not have production capability of either 20mm guns or ammo. They could produce massive amounts of .50 guns and ammo.
A related fact is the Germans said it took 26x20mm shells to bring down a B-17 while only 3x 30mm (all averages).
Also in the Eastern theater the USAF quickly added semi armor piercing incendiary rounds to ignite the unarmored Japanese fuel tanks which appears to have been extremely effective. In this case 20mm discussion is moot as the .50 was sufficient.
But that was not my comment. It is that the 6 or 8 .50 were good enough for the day, and did not see a need to switch to 4x20mm.
They also could and did produce lots of 20mm, the fact it was useless wasn't the fault of the producers, but the designers.In WWII the US did not have production capability of either 20mm guns or ammo. They could produce massive amounts of .50 guns and ammo.
That I understand and your comments on the 40mm as well.Nor did I claim the US should stick with the .50 for Kamikaze as AAA. I brought it up to show there were situations where the 20mm was NOT effective.
Remembering that on the Me109 you could only carry one weapon there is logic to making it as effective as possible. I am ignoring the extra 2 x 20mm as it had such a serious impact on performance. It worth remembering that the RAF and France post war used the german ideas and produced the Aden and Defta 30mm cannon, guns widely used in many nations so there must have been some logic to the approach.A related fact is the Germans said it took 26x20mm shells to bring down a B-17 while only 3x 30mm (all averages). So their choice was to develop a 30mm they could put on anything at the cost of very low MV. I do not remember ever reading of a large change in bomber loss rates when this put into service. So merely comparing round energy seems to be unrelated to effectiveness in combat. There must be other factors that were more important.
On this we will have to disagree. A 0.50 bullet is normally going to knock a small hole going in and a small hole going out. If it hits something then there is a good chance that the object will be seriously damaged or destroyed. A 20mm is going to cause a hole going in and all sorts of holes all over the place when the warhead goes off. A 20mm is far more likely to cause serious damage than the 0.50. The rates of fire were similar (RAF Hispano II) and the balistics were pretty close as well so they don't really factor into the equation.And back to 'alot more damage' I disagree from the combat result for the fighters that used 4 (or even 2) 20mm. The results were around the same. Germans were known to shoot down 5+ planes a day with the FW-190 but not with the ME-109. The USAAF had about the same success with the 6 or 8 .50 cal setup. They did it with different damage types. The explosive shells tend to shred lightweight parts over a larger area. The .50 cal damage hard parts, (engine props, etc.) when they actually hit them. So it s trade of similar hit probability vs end affect.
I agree that the US didn't ahve a reliable 20mm until the closing days of the war but disagree with the statement about not having a reliable gun until 1958. The post war 20mm guns fiitted to the USN aircraft were copies of the UK Hispano II and Hispano V both of which saw significant service and were perfectly reliable. These weapons on the USN aircraft could of course have been used in USAAF aircraft.Also the USAAF never had reliable 20mm it was not really an option. They went through at least 4 versions before ending up with the Colt version around 1958 or so. I can't find any discussion as why the P-38 did not swap out the 20mm for a .50. But in the East many B-25's were converted and then an actual standard version with a hard nose and 8x .50 plus 4 on the sides was created. Again probably because the .50 was plentiful and got the job done.
In which case you have to ask yourself why the USN were so keen to have 20mm guns on their aircraftAs I said before simply looking at only technical specs is of no consequence. In war you fight with what you have and modify/invent as needed.
Also in the Eastern theater the USAF quickly added semi armor piercing incendiary rounds to ignite the unarmored Japanese fuel tanks which appears to have been extremely effective. In this case 20mm discussion is moot as the .50 was sufficient.
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A related fact is the Germans said it took 26x20mm shells to bring down a B-17 while only 3x 30mm (all averages). So their choice was to develop a 30mm they could put on anything at the cost of very low MV. I do not remember ever reading of a large change in bomber loss rates when this put into service. So merely comparing round energy seems to be unrelated to effectiveness in combat. There must be other factors that were more important.
And back to 'alot more damage' I disagree from the combat result for the fighters that used 4 (or even 2) 20mm. The results were around the same. Germans were known to shoot down 5+ planes a day with the FW-190 but not with the ME-109. The USAAF had about the same success with the 6 or 8 .50 cal setup. They did it with different damage types. The explosive shells tend to shred lightweight parts over a larger area. The .50 cal damage hard parts, (engine props, etc.) when they actually hit them. So it s trade of similar hit probability vs end affect.
Also the USAAF never had reliable 20mm it was not really an option. They went through at least 4 versions before ending up with the Colt version around 1958 or so. I can't find any discussion as why the P-38 did not swap out the 20mm for a .50. But in the East many B-25's were converted and then an actual standard version with a hard nose and 8x .50 plus 4 on the sides was created. Again probably because the .50 was plentiful and got the job done.
As I said before simply looking at only technical specs is of no consequence. In war you fight with what you have and modify/invent as needed.
That is a generalization not born out by combat. Numerous B-17s and P47's came back with severe 20mm damage and flew home. Shredding the skin basically doe snot bring plane down, a critical system or several less critical systems must be damaged/destroyed. The 20mm could not destroy an engine in one shot a .50 cal can, same with armor plate (typically). Any system hit by a .50 is at least severely damaged is had too much penetration. I have seen many gun cameras of many German fighters using 20mm and the plane they shot would at first lose sheet metal. It generally took a several shots before they finally found a soft spot to damage the plane enough to down it. When gun camera from US fighters were compared in the east once an SAPI round hit the fuel tank they always burned, a 20mm HE does not start fire like that. Against the Germans, IHMO the .50 cal fired until the engine quit, the pilot was killed, or the fuel tank flamed. Time on target is roughly the same so from that limited evidence the gun setups were equal.On this we will have to disagree. A 0.50 bullet is normally going to knock a small hole going in and a small hole going out. If it hits something then there is a good chance that the object will be seriously damaged or destroyed. A 20mm is going to cause a hole going in and all sorts of holes all over the place when the warhead goes off. A 20mm is far more likely to cause serious damage than the 0.50.
I will repeat the .50 was good and successful during WWII vs 20mm.
The 20mm was unreliable to the US as defined by the continued use of the 6x.50 setup until Vietnam as front line fighter main armament. Yes there were many choices investigated, models, experimental guns and aircraft (and rocket or missiles) and other stuff. But they were not the primary system in use in US Air combat until Vietnam.
If 4x 20mm vs 6 x .50 was such and overpower massive difference then the US(AAF) either screwed up so bad for over 20 years then you all know better than the people who were then in charge or it was not enough difference at that time to persue. I chose the later.
As far as every Air force wanting the 20mm, that is an unsupported claim not a fact never heard from anyone myself, and Russia went to 23mm or large because they only had 1-3 guns on a fighter had to deal with bombers.
Also the Russians used 1 20mm and 1 .50 (there 12.7 mm) on most of the production fighters in WWII. Again 4 20mm were no needed in there opinion. And I find it hard to believe if the .50 sucked so bad for country who found away to produce ungodly amounts of tanks, aircraft and trucks they would have made more 20mm cannons.
That is a generalization not born out by combat. Numerous B-17s and P47's came back with severe 20mm damage and flew home. Shredding the skin basically doe snot bring plane down, a critical system or several less critical systems must be damaged/destroyed. The 20mm could not destroy an engine in one shot a .50 cal can, same with armor plate (typically). Any system hit by a .50 is at least severely damaged is had too much penetration. I have seen many gun cameras of many German fighters using 20mm and the plane they shot would at first lose sheet metal. It generally took a several shots before they finally found a soft spot to damage the plane enough to down it. When gun camera from US fighters were compared in the east once an SAPI round hit the fuel tank they always burned, a 20mm HE does not start fire like that. Against the Germans, IHMO the .50 cal fired until the engine quit, the pilot was killed, or the fuel tank flamed. Time on target is roughly the same so from that limited evidence the gun setups were equal.
This is clearly wrong. I will not add to what others have posted. The reliability statement is also wrong for the USN aircraft fitted with copies of the British Hispano II and VI will repeat the .50 was good and successful during WWII vs 20mm. IF anyone wants to extend that beyond what I said that we need a new topic.
The 20mm was unreliable to the US as defined by the continued use of the 6x.50 setup until Vietnam as front line fighter main armament. Yes there were many choices investigated, models, experimental guns and aircraft (and rocket or missiles) and other stuff. But they were not the primary system in use in US Air combat until Vietnam.
No one is saying the USAAF screwed up, for the requirements they had in WW2 the 6/8 x 0.5 was good enough and did the job. Had they gone up against aircraft such as the B17 or IL2 then the problem would have magnified.So all the history off weapon development and technical data is moot when you look at the actual use and combat effectiveness.
If 4x 20mm vs 6 x .50 was such and overpower massive difference then the US(AAF) either screwed up so bad for over 20 years then you all know better than the people who were then in charge or it was not enough difference at that time to persue. I chose the later.
Actually it is borne out by combat. The IJAF believed that 4 x HMG was sufficient until they went up against heavy bombers and then they switched to 20mm as fast as they could. The Japanese HMG was a copy of the USAAF 0.5. The Lutwaffe also relied on cannon against heavy bombers. Every nation that went against heavy bombers went for cannon and left the HMG behind.That is a generalization not born out by combat. Numerous B-17s and P47's came back with severe 20mm damage and flew home.
Shredding the skin basically doe snot bring plane down, a critical system or several less critical systems must be damaged/destroyed. The 20mm could not destroy an engine in one shot a .50 cal can, same with armor plate (typically). Any system hit by a .50 is at least severely damaged is had too much penetration.
You see sheet metal as its pushed outwards by the exploading warhead, the slipstream gets itt and its pulled off. You don't see on a camera film the damage being done insde the aircraft.I have seen many gun cameras of many German fighters using 20mm and the plane they shot would at first lose sheet metal. It generally took a several shots before they finally found a soft spot to damage the plane enough to down it.
Do you think they would show gun film of aircraft that got away? and yes a 20mm would do far more damage than a 0.50When gun camera from US fighters were compared in the east once an SAPI round hit the fuel tank they always burned, a 20mm HE does not start fire like that.
As mentioned before for the USAAF the 0.50 was good enough. You clearly believe that it was at least the equal of the 4 x 20mm in which case you need to ask yourself why did the USN want to use the 20mm?Also when you read the biographies of US fighter pilots I do not ever remember hearing anyone state 6 or 8 .50 cal was not sufficient. On the contrary the guys flying the P-47 seem to universally acknowledge the value (firepower) of the 8x.50cal.
All airforces British, Italian, Japanese, French, Russian went to 20mm during the war, only the USAAF stated with the 0.50 out of choice. You should also remember that the Russian 12.7 HMG was a much better weapon than the USA 0.5 and they went to 20mm. It is a very supported claim.As far as every Air force wanting the 20mm, that is an unsupported claim not a fact never heard from anyone myself, and Russia went to 23mm or large because they only had 1-3 guns on a fighter had to deal with bombers.
In the Russian opinion the 20mm was needed and the LA5 and LA 7 were armed with 2 or 3 of themAlso the Russians used 1 20mm and 1 .50 (there 12.7 mm) on most of the production fighters in WWII. Again 4 20mm were no needed in there opinion. And I find it hard to believe if the .50 sucked so bad for country who found away to produce ungodly amounts of tanks, aircraft and trucks they would have made more 20mm cannons.
from: Modifications and Attempts at Standardization[In 'Guns of the Royal Air Force 1939-1945' by G.F. Wallace - who was there - there is an account of British tests of the British and US Hispanos which took place early in 1942. The British were unhappy with initial supplies of the American-made guns: "there were frequent misfeeds and lightly struck cap stoppages, and the life of several small components was very short" so a comparative test between one British and three American guns was set up. The intention was to fire 5,000 rounds from each gun without replacing any components. "The British gun fired the full programme but the performance of the American guns was so bad that in each case the trial had to be abandoned before the 5,000 rounds had been fired." The British gun experienced 19 stoppages in firing 5,012 rounds. The American guns experienced 67 stoppages out of 4,092, 97 out of 3,705 and 94 out of 2,610 respectively. Incidentally, Wallace states that the US guns were "beautifully made and better finished than our own" and expressed surprise that although lightly struck caps were a major source of stoppages, even more frequent were mis-feeds.]