Why was the US the only nation to rely on the 50

[CurzonDax]

But I think the bottom line is this, logistics and supply. Its great weapon, but not the best, and it will do the job well, not great but well. Look at Pratt Whitney. The did build kickin engines but again supply and demand. Also the .50 has a higher cyclic reate than many cannons of its time and it has withstood the test of time, the fifties of today are not much more different than thier ones 60 years ago. Also to fire one is like to have the hand of the Goddess in your hands. Also I bet that B-17 armourors liked to carry a fifty around to install much better than a cannon!

:{)

 

[syscom3]

I dont think the Germans had armed their fighters with a full compliment of six heavy MG like the US did. remember, that when the war began for the US in 1941, there were two fighters that were designed from the outset to handle high flying "enemy" bombers. The P38 with its concentrated firepower which acted like a buzz saw, and the P47, which had eight .50's which would have ripped apart its opponant, just from the ammount of lead flying through the air.

 

[Glider]

As a defensive weapon for bombers I have always believed that the .50 was more or less an ideal weapon. It had range, accuracy and you could put twins in a turret giving you a good rate of fire. 20mm in a turret would be too heavy.
However as you will have noted to take on a Heavy Bomber I believe that you needed something bigger.

 

[carpenoctem1689]

The 12.7mm was perfect for bomber defense, because like stated above, it was lighter then cannons, had a great fire rate, good range and decent enough power to deal with interceptors. The 12.7mm, unless concentrated, or used in high numbers (six to eight) wasnt the best anti-bomber weapon, because youd have to get in close enough to be in the enemies defensive range, and you couldnt bring him down too quickly. But cannon arent as effective against fighters because they have a slower rate of fire, and that decreases the chance of hitting a small, fast aircraft. So they tended to go overboard with 12.7mm (p-47 had eight, some say adequate, i say a little too much) or go with all cannon (Tempest, some spitfires and hurricanes, typhoon) or my favorite, mix up two cannon, two machine guns. The 12.7mm was perfect fopr defense, and adaptable to attack.

 

[syscom3]

The problem with mixed armorment is the different trajectories the shell would have. I think some P38 pilots disliked the 20mm because of that.

I always did think the B17/B24/B29 should have have a pair of 20mm or 30mm cannons.

Off topic, but the B52's had a .50's for the tail gunner, untill the advent of the vulcan cannon.

 

[lesofprimus]

Yes syscom, Ive heard the same thing from some Vets, concerning the 20mm trajectory compared to the .50's...

Then again, Ive also heard that some loved the 20mm for the extra puch it carried.... You can never make everyone happy all the time....

(except the Sturmgruppen pilots)

 

[CurzonDax]

There is also the cyclic rate. One of the reasons why the P-47 and the Lightning could plow the field was the higher cyclic rate of the .50 compared to the cannons of its contemporaries. Yes the rounds were smaller and the range was shorter in the .50 but more bullets were flying downrange than a cannon.

:{)

 

[Jank]

The range of the .50BMG was not shoretr than any of the 20mm rounds used in the war.

The .50 had a flater trajectory due mostly to its high sectional density, ballistic coefficient and velocity.

 

[Jabberwocky]

Lunatic posted a very good giude to the ballistic properties of various aerial weapons of WW2.

http://members.cox.net/rg_lunatic/gunpage/

and Rings PRO page also has an excellent technical comparison between the various fighter armaments, if his service privider ever fixes the bloody hosting problems it has been having!

 

[Glider]

All guns are different and there was a significant difference between the best and worst of any calibre. However if we are comparing the USA M2 .50 against the standard British Hispano II the cyclic rate was similar.

M2 13.5 rds per second
20mm 10 rds per second

slower certainly but the 20mm was quick enough for the job.

 

[syscom3]

Doesnt the 50 cal have a longer sustained rate of fire?

 

[Glider]

To be honest I don't know but the ideal burst for any fighter pilot was 2 seconds so I don't really know how important that was.

At the end the M2 was more accurate at long range as the gun ballistics were better but the 20mm carried 8-10 times the explosive so was far more effective when it hit. As the M2 wasn't 8-10 times more accurate the advantage was definately with the 20mm.

 

[Jank]

The 20mm did not carry "8-10 times the explosive" compred to the .50 BMG because the .50 BMG bulets had no explosive. Ball, armor piercing and incindiary. Thats it.

 

[Glider]

Let me rephrase that to Incendary material.

 

[Jabberwocky]

A 20mm Hispano HEI (High Explosive Incidenary) round carries about 10 1/2 grams of explosive material.

A 12.7 M8 API (Armour Piercing Incidenary) carries about 0.85 grams of incidenary material.

So a Hispano HEI round carries about 12 time the amount of chemical material that a .50 cal round does.

Obviously, the 20mm HEI round is going to have significantly more blast/overpressure, fragmentation and ingintion effects than the smaller M2 round.

Standard belting for the Hispano from 1942 was a 50/50 mix of AP ball and HEI. I'm not sure about the M2 belting, but I think that it was something like API-AP-API-AP-Tracer.

 

[wmaxt]

The tracer round had a different trajectory than other .50 pounds.

As for loadout, often in the Pacific P-38 groups used no tracer rounds and their kill count went up. The count went up because they relied on the gun site rather than the tracer for more accurate aiming and the lack of a tracer (no warning for the target) allowed a second try if the first didn't connect.

wmaxt

 

[DerAdlerIstGelandet]

Also the .50 has a higher cyclic reate than many cannons of its time and it has withstood the test of time, the fifties of today are not much more different than thier ones 60 years ago.
:{)

The .50's of today are the same one from 60 years ago. They have just been overhauled. We have several .50's in my unit and they were manufactured in 1942.

I dont think the Germans had armed their fighters with a full compliment of six heavy MG like the US did.

Depends on the fighter you are talking about:

Dornier Do-335B-2
Two 20mm MG 151/20 machine guns above the nose
Two 30mm Mk 103 cannon mounted in the wings.
One 30mm Mk 103 cannon firing through the propellor hub.

Fw 190A-3
Two 7.92mm MG 17 machine guns above engine.
Two 20mm Mg 151/20 cannon mounted in wing root.
Two 20mm MG/FF cannon in outer wings.

He 219A-2/R1
Two 20mm MG 151/20 Cannon in wing roots.
Two or Four 20mm MG 151/20 Cannon in belly tray.
Two 30mm Mk 108 cannon in Shräge Musik mount.

He 219A-7/R1
Two 30mm Mk 108 Cannon in wing roots.
Two 20mm MG 151/20 Cannon in belly tray.
Two 30mm Mk 103 Cannon in belly tray.
Two 30mm Mk 108 cannon in Shräge Musik mount.
Ammunition: 100 rounds per gun

He 219A-7/R2
Two 30mm Mk 108 Cannon in wing roots.
Two 20mm MG 151/20 Cannon in belly tray.
Two 30mm Mk 108 Cannon in belly tray.
Two 30mm Mk 108 cannon in Shräge Musik mount.
Ammunition: 100 rounds per gun

Bf-110G

Armament:
Nose: Fixed firing forward
Two 30mm Mk 108 Cannon with 135 rounds per gun
Two 20mm MG 151 Cannon with 300 rounds(port) and 350 rounds(starboard)
And
Two 20mm MG 151 Cannon in Shrage Musik Installation (Firing Obliquely forward)
Or
Two 7.92mm MG 81 in rear cockpit

Optional:
Waffenwanne 151Z ventral tray housing two forward firing 20mm MG 151 cannon

 

[102first_hussars]

I know that other nations, like Germany and Japan changed caliburs late in the war, but why was America the only one favoring the high calibur machine gun rounds from the get go? As for the rebuttle that Germany and Britain used 20mm, that is not a machine gun. That is a cannon.

Well Canada still uses the 50.cal as a platform machinegun and Ill tell you that weapon is a bastard to carry in the feild, shit that thing weighs close to 100lbs, personally I wouldnt have even gone with the lighter 30.cal.

But the Brits and Canadians used 50.cals in our bombers and spits, and in some cases we mounted them oon our shermans.

 

[syscom3]

The german fighters looked like they got plenty of cannon, but not 12.7mm MG

 

[DerAdlerIstGelandet]

[
Well Canada still uses the 50.cal as a platform machinegun and Ill tell you that weapon is a bastard to carry in the feild, sh*t that thing weighs close to 100lbs, personally I wouldnt have even gone with the lighter 30.cal.

It weighs more than that. In order for a unit to carry it on foot, you have to break it down into 3 parts. The Barrel, the Reciever Assy, and the Tripod Assy. It takes 3 people to carry the .50. That is why in the US, it is only a crew served weapon and is mounted on Tanks, Helicopters, and Vehicles now adays.

The german fighters looked like they got plenty of cannon, but not 12.7mm MG

For MG's they did not have 12.7mm anyhow. They used 7.7mm and 13mm mostly.