1½ pr Vickers Mark B ammo?

[Tony Williams]

As well as the 1½ pr Vickers Mark A (the naval automatic gun, using 37x124R ammo), there was a semi-automatic Mark B fitted experimentally to two seaplanes just before WW1: a Short S.81 and a Sopwith No.127.

I have always assumed that the Mark B used the same ammo as the Mark A, but I have just noticed some different information in Friedman's Naval Weapons of World War 1, as follows (Mark B data first, Mark A in brackets):

Barrel length: 38 in (62 in)
Chamber volume: 4.42 in[SUP]3 [/SUP](7.66 in[SUP]3[/SUP])
Propellant charge: 397 grains Cordite (1,042 grains)
Chamber pressure: 9 tons in[SUP]2[/SUP] (17 tons in[SUP]2[/SUP])
Muzzle velocity 1,200 fps (2,100 fps)
Projectile weight 1.5 lbs in both cases.

So, assuming that the author's data is correct, what was this much smaller cartridge case? Since I have never heard of any such, I am wondering if it might have been a standard 1 pr (37x94R) case loaded with a 1.5 lb projectile.

Has such a combination (with the projectile crimped in) turned up? Can anyone shed any light on this?

 

[womble]

Tony

I have a 1 1/2 pdr case length is 122mm it is a VSM Dummy it has had a hard life, been dropped a few times so possibly the case length could be + 1 or 2 mm, please see attached photos, hope this helps.

Regards Womble

 

[Weasel]

Hi Womble,
Fantastic round, thanks for posting a picture of it for us, best regards Weasel.

 

[Tony Williams]

I have a 1 1/2 pdr case length is 122mm it is a VSM Dummy it has had a hard life, been dropped a few times so possibly the case length could be + 1 or 2 mm, please see attached photos, hope this helps.

Thanks for that, Womble, but that's the 1.5 pdr case which is used in the "Mark A" data in my first post. The one I am looking for is clearly going to be smaller, given the much smaller chamber volume quoted.