Vickers S gun 40 X 157R tank buster round

[Quatermass]

Ive managed to get hold of an S gun round, searching the forum I couldnt
find any information so I thought id start a thread. Perhaps other members
could post pictures and information.

Compassion of British 40mm projectiles:

S Gun projectile overall length 164mm.
40mm Bofors AP projectile overall length 156mm.
2 PR AP projectile overall length 132mm.
2 PR Naval WW1 common pointed projectile 142mm approx.

AP Mk I 2lb 5ozs / 1.13kg (Wallace gives a shot weight of 2lb 7ozs / 1.22kg)
AP Mk V 3lb / 1.36kg

Clarke gives details thus: armour-piercing MkI. weighing 2 1/2lb, it was a
solid projectile with a tungsten nose which could penetrate 50mm (1.95in) armour
(the round is also illustrated with a line drawing of a 3.7cm flak AP round with
some very strange dimensions!) Clarke certainly seems mistaken on the tungsten
nose, a good case of not trusting a single source of information.

souces:
The guns of the R.A.F. 1939-1945 G.F. Wallace
Flying guns world war II. Anthony G. Williams & Dr Emmanuel
Gustin
British aircraft armament Vol 2. R Wallace Clarke

 

[Falcon]

Nice round. Please could you post a photo of the headstamp.

 

[StielGr]

There was a thread started a few years ago that might help.

http://www.bocn.co.uk/vbforum/threads/31093-RAF-20mm-Hispano-and-40mm-Vickers-S-help

PC

 

[Quatermass]

Thanks StielGr, thats what i was looking for.
Falcon, picture of the base attached.

 

[Falcon]

Thanks for the photo. It's unusual that it is a normal 2 Pounder headstamp. As far as I knew all of these had a special 40 M/M headstamp.

 

[SG500]

Thanks for the photo. It's unusual that it is a normal 2 Pounder headstamp. As far as I knew all of these had a special 40 M/M headstamp.

Falcon, have a look at the headstamp on the link (post 8)
http://www.bocn.co.uk/vbforum/threads/31093-RAF-20mm-Hispano-and-40mm-Vickers-S-help
It doesn't refer to 40mm and I've had 3 of them over the years all with similar headstamps, none with reference to 40mm.
Interestingly the one I have has "AP" stencilled on the base.
Dave.

 

[2pounder]

Just had a look at the paperwork I have on the 40mm SBH ammunition and various notes refer to using the 2pr No.1 Mk II primed No.27 ( as the no.16 was not suitable at low temps.) one illustration shows this stamping on the base.

 

[Falcon]

Maybe I was wrong there then. I am pretty sure some cases marked "40 M/M" do exist.

 

[2pounder]

I'll take a flier on the 40m/m case and say its an export type much as the 1 1/2pr are marked 37mm but no broad arrow.

 

[Tony Williams]

Two things seem pretty clear: "40 mm" stamped S-gun cases do exist, but a lot of (most?) S-gun ammo doesn't use them. I've always understood the 40 mm-stamped cases to be rare.

Logically, in circumstances like this one would expect that early production would use the general headstamp until they got around to making a specific 40mm bunter, but I don't know if that's what happened in this instance. How do the dates tie up?

I'd be surprised if this had anything to do with export - this ammo was only made in wartime and I've never heard of any attempts to sell it abroad.

 

[Falcon]

I saw this headstamp on a cut down case at a car boot sale a few years ago. The rim was exactly the same size as a 2 Pounder. I didn't buy it as they wanted 15 for a ruined case that was cut off to about 2 inches long and had been engraved on the side.

 

[hangarman]

I saw this headstamp on a cut down case at a car boot sale a few years ago. The rim was exactly the same size as a 2 Pounder. I didn't buy it as they wanted 15 for a ruined case that was cut off to about 2 inches long and had been engraved on the side.

View attachment 63374

My case is stamped as per Falcons drawing. The projectile is stamped

AP 40M/M VT
JMB
1 / 43

Hangarman

 

[Falcon]

It is an interesting headstamp as it is not laid out in the usual way that British headstamps are. There is also no obvious date marking.

 

[StielGr]

My case is stamped as per Falcons drawing. The projectile is stamped

AP 40M/M VT
JMB
1 / 43

Hangarman

The projectile I have is also produced by JMB. James Mackie, Belfast.
Unfortunately it has suffered from some corrosion.

PC