Venomstick121
Airman 1st Class
- 291
- Dec 21, 2023
I am talking about the f-4u and p-51 for the most part
Why did the US ww2 fighters have 50 cals instead of 20mms like their european cousins
- Thread starter Venomstick121
- Start date
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Combination of several factors…
Weight
Amount of ammo that could be carried
Primary targets - the primary target of US fighters were lightly armored fighters. .50 Cals are more than enough to take them down.
The German's used 20mm, hut what was their primary target? Bombers…
Weight
Amount of ammo that could be carried
Primary targets - the primary target of US fighters were lightly armored fighters. .50 Cals are more than enough to take them down.
The German's used 20mm, hut what was their primary target? Bombers…
MIflyer
1st Lieutenant
Well, logistics was a big factor. No one else had to support so much in so many different theaters of war than the USA. No one else can even distantly close.
And for everyone else, upgrade to 20MM was from .30 cal. Big difference from .50 cal!
The introduction of .50 cal armor piercing incendiary API ammo made the .50 cal very effective, probably superior to 20MM in many cases. There were cases in which USN F6F's shot down Japanese Vals with ONE round of API. When the guns basically ran out of ammo they often could get a single round into the chamber by activating the charging mechanism. And with the USS Laffey begging its fighter cover not to leave it at the mercy of some Kamikazes they had an incentive to give that approach a try.
Finally, except for the first 6 months or so the USA was on the OFFENSE. 20MM and 30MM are useful against heavily defended bombers. An Axis fighter attacking of tight formation of B-17's or B-24's and scoring a kill without a getting his butt shot off was pretty low. Statistics showed about 1% chance of scoring a kill in one pass, even with 20MM. And if you make 100 passes at US bomber formations they are likely to hurt you. But the USA, on the offense, had little reason to worry about large formations of heavily armed Axis bombers.
And for everyone else, upgrade to 20MM was from .30 cal. Big difference from .50 cal!
The introduction of .50 cal armor piercing incendiary API ammo made the .50 cal very effective, probably superior to 20MM in many cases. There were cases in which USN F6F's shot down Japanese Vals with ONE round of API. When the guns basically ran out of ammo they often could get a single round into the chamber by activating the charging mechanism. And with the USS Laffey begging its fighter cover not to leave it at the mercy of some Kamikazes they had an incentive to give that approach a try.
Finally, except for the first 6 months or so the USA was on the OFFENSE. 20MM and 30MM are useful against heavily defended bombers. An Axis fighter attacking of tight formation of B-17's or B-24's and scoring a kill without a getting his butt shot off was pretty low. Statistics showed about 1% chance of scoring a kill in one pass, even with 20MM. And if you make 100 passes at US bomber formations they are likely to hurt you. But the USA, on the offense, had little reason to worry about large formations of heavily armed Axis bombers.
US-manufactured 20mm cannons being badly unreliable had a lot to do with that.
SaparotRob
Unter Gemeine Geschwader Murmeltier XIII
Heck, even I know that.
MIflyer
1st Lieutenant
The 20MM cannon used in Marine F-4U deployed to Okinawa were found to jam at high altitudes. The reason given was that they had skipped the high altitude testing.
UK had to move all this around, Commonwealth small arms calibers and Lend Lease received from USA
38 S&W
9mm
455 Webley
45 Auto
303
30-06
8mm Mauser
50 Browning
50 Vickers
55 Boys
15mm BESA
J.A.W.
Banned
Did the British conceal-carry security cops & spy chaps - carry the small calibre Walther, back then?
Pocket Pistols in 25 or 32acp, Hmm. I know the French and Germans used those calibers, but haven't seen for official British Armed forces.
Alan Stevens
Airman 1st Class
- 113
- May 24, 2023
20 mm was needed for defeating aircraft like the B-17, B-24, B-29 and Lancaster.
50 cal with tracer and AP was sufficient for defeating single engine and twin engine aircraft.
50 cal with tracer and AP was sufficient for defeating single engine and twin engine aircraft.
J.A.W.
Banned
Which Spitfire wing accommodated the 6 x .50" fit-out? I can visualise 4, but the Mustang III was compared unfavourably for that "Light"
armament, even with the Spit, let alone earlier 4 x 20mm Mustangs, which did comply with the RAF 'standard' (& carried UK-Hispanos).
I meant slower than when fitted with 8 x 0.303".
J.A.W.
Banned
So the 6 x.50" was too heavy, & slowed the Spit down that way - rather than by the drag of protruding cannon?
(Ever seen the Martin-Baker M-B III with the 6 x 20mm (mock-up) fit out, they even designed a more compact belt feed system.)
As far as I know it was the drag of the protruding cannon that made the difference. In 1940-41 when they started fitting cannon to RAF fighters, the 0.5cal wasnt a viable option, not reliable, low rate of fire and USA not in the war. The Spitfire could carry 4 cannon and 4 x 0.303 " there were mock ups with 6 x 20mm cannon
ThomasP
Senior Master Sergeant
In service the 4x 20mm of the Hurricane Mk IIC lowered the Vmax by about 1.5-2 mph per 20mm ( total of about 6-8 mph). I have read that the Spitfire Mk VB/C & Mk IX had their Vmax reduced by about 2-3 mph per 20mm installed (total of about 4-6 mph for the 'B' wing and 8-12 mph for the 'C' and universal wing).
The cannon barrels, blisters and stubs all added drag to the Spitfire costing speed, about 10mph or so.
Clayton Magnet
Staff Sergeant
- 902
- Feb 16, 2013
