If you were a fighter pilot in WWII, would you rather have the high rate of fire of the 50 cal, or the hitting power of the 20mm? I personally feel the 50 cal was plenty hard hitting enough to take out ANY aircraft, and its high rate of fire made it even more effective...the slow rate of fire for the 20mm meant you had to be a much better marksman...
50 cal (high rate of fire) vs 20mm cannon (hitting power)
- Thread starter grampi
- Start date
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The Italian .50 was good for 700 rd/min (down to 550 rd/min when synchronised). Shvak was a bit faster, up to 800 rd/min un-synchronised. Muzzle velocity was about the same. HE shell for the Breda .50 was 34g, for Shvak was 96 g heavy.
20 mm FTW.
Clayton Magnet
Staff Sergeant
- 854
- Feb 16, 2013
The 20mm Hispano and Browning M2 had similar rates of fire, and similar muzzle velocities.
swampyankee
Chief Master Sergeant
- 3,954
- Jun 25, 2013
The USN rated the 20mm as three times as effective as the 0.5 in, at least when it worked. I'll take a working Hispano.
Shortround6
Major General
AS Tomo and CM have pointed out the rates of fire for both calibers of gun varied quite a bit.
For an american pilot the difference in rate of fire was 600rpm for the 20mm and 800rpm for a wing mounted .50cal (give or take) so the difference in rate of fire was not that different per gun. A four cannon Corsair was firing 40 20mm shells per second, a six .50 cal Corsair was firing 78 or so .50 cal bullets per second. The 20mm shells had about the same muzzle velocity and weighed almost 3 times as much, and they exploded (mostly)
Most service 20mm cannon fired at least 500rpm (early German and Japanese guns) while later German (MG 151) and Japanese army (Ho-5 cannon) fired at 700-750 rounds a minute. U.S. .50 cal fired 1 to 2 bullets more per second. or about 13% more at best. The Axis 20mms hit harder per projectile.
We have a lot of threads on the subject.
The U.S. 50 did the job but it was no wonder weapon.
For an american pilot the difference in rate of fire was 600rpm for the 20mm and 800rpm for a wing mounted .50cal (give or take) so the difference in rate of fire was not that different per gun. A four cannon Corsair was firing 40 20mm shells per second, a six .50 cal Corsair was firing 78 or so .50 cal bullets per second. The 20mm shells had about the same muzzle velocity and weighed almost 3 times as much, and they exploded (mostly)
Most service 20mm cannon fired at least 500rpm (early German and Japanese guns) while later German (MG 151) and Japanese army (Ho-5 cannon) fired at 700-750 rounds a minute. U.S. .50 cal fired 1 to 2 bullets more per second. or about 13% more at best. The Axis 20mms hit harder per projectile.
We have a lot of threads on the subject.
The U.S. 50 did the job but it was no wonder weapon.
Folks, my opinion depends on whether you are taking on a 4-engine bomber or a light/medium bomber/fighter. I want more lead heading down range to hit a Japanese or German fighter since they are maneuverable while I would want a 20mm for taking on a heavy bomber because it takes a lot less of them to bring down a heavy bomber (plus they can have an explosive round). The USAAF and USN were very lucky that they were taking on flammable IJN/IJAAF aircraft and German fighters with their .50 cal (same goes for the RAF using 6-8 .303 round guns to take on HE-111/JU-88/DO-17's). Just my opinion.
As has been said there are many threads on this. In 1939 the RAF armament was 8 x 303 MGs and that was considered devastating, enough for a 2 second burst to take down a bomber, the effectiveness was increased with incendiary rounds. However even then the preferred armament for a fighter was for 4 x 20mm cannon, that's what the Whirlwind was all about. Prior to the USA entering the war the RAF standard armament for fighters was 4 x 20mm cannon. This was fitted to the Hurricane Mk2, the Typhoon Tempest Mosquito and Beaufighter. The Spitfire was an exception, they started to fit cannon in 1940, and had problems getting them to work, but even when it did work the decision was to have 2 cannon and 4 x 0,303mgs for various reasons, weight at high altitude and heating. While RAF pilots may have preferred cannon in the BoB, it is a fact that the LW ran out of serviceable bombers and gave up. But the Spitfire wasn't limited to 2 cannon and 4mgs by any law, some carried 4 cannon and 4 x 0.303 mgs which would ruin anyone's day.
There are statistics already discussed about rate of fire, you can then discuss weight of fire and effect of fire but the LW had another statistic of how many hits you could land in a "pass" and how effective those hits would be. This is concerned with bringing down a 4 engine bomber, but the problem then becomes the ballistics of large calibre rounds even rockets that can devastate a large bomber become increasingly unlikely to hit a fighter.
There are statistics already discussed about rate of fire, you can then discuss weight of fire and effect of fire but the LW had another statistic of how many hits you could land in a "pass" and how effective those hits would be. This is concerned with bringing down a 4 engine bomber, but the problem then becomes the ballistics of large calibre rounds even rockets that can devastate a large bomber become increasingly unlikely to hit a fighter.
Some carried 2 x 20mm and 2 x 0.5 on the universal wing. They could be fitted with 4 x 20mm but this created handling issues. The 20 series Spitfires which had a new wing and cut of hispanos seemed to work fine.
It was discussed on the forum here, some Spitfire MkVc had 4 cannon and 4 mgs, used in the Med theatre, I was surprised to read it too.
fastmongrel
1st Sergeant
If your engine is hit by a couple of .50 armour piercing incendiaries they might hit an oil line or a fuel line. If your engine is hit by one 20mm HE round that explodes you have lots of hot shrapnel spraying all over the engine compartment like shotgun pellets. Two.50 rounds is two hits one 20mm round is lots of hits.
fastmongrel
1st Sergeant
There's a picture of a Spitfire with 6 cannon. Don't know if they were dummies maybe for aerodynamic testing but imagine being hit by 6 20mm HE rounds. That's one burst B29 killing power.
Recommend reading this article about a P-61 with 20mm and .50 cal's trying to take down a B-29 https://www.flightjournal.com/wp-content/uploads/2011/12/splash1.pdf
8 x 303's aren't going to take down a B-17 or B-29 very easily while I agree completely 8 x 303's will do great against a LW DO-17/JU-88/HE-111.
The standard armament of a Mosquito or Beaufighter would ruin anyones day. 4 x 20 mm firing at 600 (as a round number) RPM means a 2 second burst is 80 shells, it wouldn't only wreck an aircraft but made a mess of shipping too, it wouldn't sink a ship but damage much of the superstructure. The same could be said of a P-47s 8 x 0.5 mgs. Two seconds of those would wreck any aircraft made. One thing I noticed from reading pilots memoirs, it didn't seem to matter where a Hurricane or Spitfire was hit by a cannon shell, if it wasn't in the engine, wing tips or tail the pilot frequently got injured in some way by splinters, usually in the legs.
fastmongrel
1st Sergeant
I have seen various rates of fire from 600 to 700 for the Hispano MkII so I usually write 650 rpm not that it makes a great deal of difference it will just make you 10% deader. The later Hispano MkV was 750 rpm.
As I said it is a round and not unreal number (600 is 10 per second), the advised firing time for pilots was 2 seconds, no reason at all why it couldn't be longer.
From what I have read it didn't matter what plane your were in, if the rounds entered off bore they bypassed the rear armor and pilots got arm and leg injuries.
A.G. Williams
Airman 1st Class
- 182
- Oct 10, 2020
Here's a detailed analysis of the effectiveness of different kinds of WW2 fighter armament: WORLD WAR 2 FIGHTER GUN EFFECTIVENESS
wuzak
Captain
It was a mockup on the prototype Mk IV/XX/XII Griffon Spitfire.
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