Tony Williams
Well-Known Member
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?
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?