Primary Source WWII Era US/British 20mm Cannon Data (TM 9-2200)

[Vermillion]

Ah the wonders of the goodies you can find on the internet  

The other day I found an original copy of TM 9-2200 War Department Technical Manual; Small Arms, Light Field Mortars and 20mm Aircraft Guns, 11 October 1943 available for sale from a used book dealer for $25 dollars. Excellent, excellent find   Its in pristine condition, and looks like it has literally never been opened except for a passing glance, and its 58 years old.  

Since there seems to be a continous debate about the American AN-M2 and British Hispano 20mm cannon (same gun, just depends on who made it) I have scanned in the pertinent parts and put them together into a nice little pdf format file.  Its 1.6 megs, and you can download it from the following link. It contains detailed data (size, weight, shell fillings, ballistic coefficent etc.) on the gun itself and the 3 different types of ammunition available for it, including photo's of each shell type.
 http://www.vermin.net/temp/TM9-2200-20mm.pdf

If you wish to keep a copy, you might want to save it to disk, since my website (and webspace) will be undergoing a massive change in the near future and its location will most likely change.

For all those Luftwobble types who have for SO long insisted that the Hispano's only used AP type ammo up until 1945, please take a good long look at the document. You will find that HE-I, AP-T, and Ball ammunition were all used at least as early as 1943 when this document was published.

Hopefully in the near future I will get the time to do the same for the US Aircraft fixed mount .50, flexible mount .50, fixed mount .30, and flexible mount .30, all of which are slightly different.

Enjoy  

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Vermillion
**MOL**, Men of Leisure

[Sturm]

Great find Verm, and another thing I was not part of the conspiracy on the 1 type of ammo  

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Sturm6 StaffelKapitän
JV44 Platzschutzstaffel
Airfield Defense Squadron

[brady]

 This is an excellent source, I have access to one at a local museum,I would love to own one and may order one my self,I seam to recall Pyro saying he had almost the whole series.

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[This message has been edited by brady (edited 03-23-2001).]

[Hooligan]

Thanks Verm.

Hooligan

[-aper-]

Hi Verm

Thx for the info!

Could you explain  me some numbers of H.E.I rounds:

As far as I understood:

Projectile with fuze = 2000 grains = 129,6 g
H.E.I filler = 174 grains = 11,3 g

My question is what was the HE/Incendiary proportion in these 11,3 grams of H.E.I.

[Vermillion]

Aper, I honestly don't know for sure.

What I posted was the entire section that was in the TM9-2200.

However, I once found the following data during some of my other research. (And its on my website)

 

The US Army's 20mm High Explosive/Incindiary cannon shell used during WWII has the following characteristics.      

Total Projectile Mass =  1565 grains
Explosive Mass = 165 grains of TNT

Source:  US Army's Small Arms Ammunition Pamphlet, 23-1 SSA.  August 1968. Picktany Arsenal. Or alternatively, US Army Ammunition Data Sheets, Small Caliber Ammuntion. TM 43-0001
 

The two round are suppose to be the same, but their overall weight is quite different. However, their filler weights are quite similar.

So if you use both sets of data together, you could maybe guess (IMO) that of the 174 grains of total HE/I filling, 165 grains were high explosive, and 9 grains were some incendiary compound.

*shrugs* Not a good answer, but all I can think of.

All I know is that the TM 9-2200 is from a war time data set, and the TM 43-001 is from a 1968 data set. So they may be talking about WWII era shell, and a post war era shell.

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Vermillion
**MOL**, Men of Leisure

[Tony Williams]

The US WW2 datasheets I have state that the Mk 1 HEI projectile weighed 0.286 lb and had a 174.25 grains filling, made up of 107.75 grains tetryl and 66.5 grains of incendiary composition.

Tony Williams
Author: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/

[Nashwan]

Tony, do you know the details of the filling for the US .50 cal AP/I round?

[Vermillion]

Nashwan, TM9-220 doesn't list a AP/I round for the .50 cal.

It lists an:
AP
Ball
Incendiary
Tracer

AP round
bullet weight: 710 grains
ballistic coefficent: 0.472 lb/sq in.
Muzzle velocity(45" barrel): 2,935 ft/sec
Muzzle velocity(36" barrel): 2,845 ft/sec
Max Range (45" Barrel): 7,600 yds

Ball round
bullet weight: 698 grains
ballistic coefficent: 0.467 lb/sq in.
Muzzle velocity(45" barrel): 2,935 ft/sec
Muzzle velocity(36" barrel): 2,845 ft/sec
Max Range (45" Barrel): 7,600 yds

Incendiary round
bullet weight: 620 grains
ballistic coefficent: 0.317 lb/sq in.
Muzzle velocity(45" barrel): none given
Muzzle velocity(36" barrel): 3,100 ft/sec
Max Range (45" Barrel): 7,600 yds
Note: It does not state what the incendiary compound is, or what its weight is.

Tracer
bullet weight total: 676 grains
tracer compound component: 70 grains
ballistic coefficent: 0.500 lb/sq in.
Muzzle velocity(45" barrel): 2,860 ft/sec
Muzzle velocity(36" barrel): 2,7300 ft/sec
Max Range (45" Barrel): 7,300 yds
Length of Trace: 1,600 yds

Thats all I have, maybe Tony has more

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Vermillion
**MOL**, Men of Leisure

[Tony Williams]

Well, I have the Definitive "History of US Small Arms Ammunition" which has 62 pages on .50 cal.....a bit much to read through, but I'll see what I can do.  

The USAAF started the war using a mix of AP and incendiary.  Later, they switched to a new API round which became standard for most purposes.

The AP M1 was a steel-cored ammo in service in 1940 (750 grains at 2,650 fps).

The AP M2 was adopted early in 1941, using a tungsten-chromium steel core (later modified to manganese-molybdenum steel because of the cost of the 4% tungsten element) and weighing 718 grains.  This was fired at 2,900 fps and could penetrate 7/8 inch of homogenous steel at 200 yards.

The incendiary M1 weighed 633 grains and contained 35 grains incendiary compound.  This was adopted in January 1942.

The API M8 was designed following examination of the Soviet 12.7mm B-32 API ammo (bet you didn't know the US owed anything to the Soviets in ammo design - well, I didn't either until I looked it up!) and was standardised in October 1943.  It weighed 662 or 649 grains (depending on the type of core used) and was fired at 2,910 fps.  Armour penetration was slightly less than the M1 AP (7/8 inch at 100 yards).

This design was basically an AP with a small quantity (12 grains) of incendiary material filling the gap between the AP core and the tip of the bullet jacket.  

The M8 was developed for ground use but adopted by the USAAF because of the difficulty B-17 crews were having with the attacking Luftwaffe fighters; the AP would penetrate but not usually do much damage, the incendiaries couldn't penetrate to the fuel tanks.

The Ordnance department recommended continued use of the M1 incendiary, mixed with the M8, because of its better incendiary effect.  It was also recommended to keep the M2 AP for ground attack and in the forward guns on bombers to confront head-on attacks.

These seemed to be the main ammo types used by the USAAF in WW2 (apart from tracers).  I believe that the M8 remained in service in the Korean War.

Tony Williams
Author: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/

[Nashwan]

Thanks for the data. Exactly what I was looking for

[Sundog]

Great info Mr. Williams and Verm. Thanks!

P.S.- So why do I keep getting a wounded pilot when shot by .50s from 400 to 600 yards on dead astern in AH?  

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Sundog
VMF-111 Devildogs
MAG-33

'Criticism is always easier than craftmanship.'

[chisel]

Cool info Mr. Williams, thanks.

Any idea as to what there definition of "penetration" was?


I've heard that the in some US tests (AFV) that penetration was cracking the plate, while other countries/testing methods required an actual hole thru the plate.

[Jigster]

bah

[This message has been edited by Jigster (edited 03-25-2001).]

[Tony Williams]

No, Chisel, I don't know how they defined penetration.  I also don't know how the "homogenous steel" they used for the tests compared with armour plate.  Anyone out there got any info?  I shall ask around.

Tony Williams
Author: Rapid Fire - The Development of Automatic Cannon, Heavy Machine Guns and their Ammunition for Armies, Navies and Air Forces.
Details on my military gun and ammunition website: http://www.users.globalnet.co.uk/~autogun/