The attached photograph shows a 23 X 139/SR T4 round.
The .9" cannon for this cartridge was developed for use as an aircraft cannon. The ordnance department of the United States Army started its development in about 1935.
The T4 was designed by Colt.
The case is based on the 28 X 199/SR (1.1" USN anti aircraft round).
It was never officially adopted and after 1945 it became obsolete.
The practise projectile is painted black with an aluminium dummy fuze.
Headstamp is CAL .90" T4 2536 - F.A.I.E.D.B
Considering its experimental the T4 rounds seem to be surprisingly easy to get hold of (I know where one is for sale if anyone is after one).
T1, T2 and T3 rounds were also produced. The T1 was a heavy weapon with a maximun firing rate of 150rpm. The T2 was supposed to be an improved Oerlikon design but was too heavy and in order to obtain the required rate of fire of 400rpm the cases had to be lubricated. The T3 had a different breech lock from the T2 but its rate of fire was the same. T1,2 and 3 catridges/rounds are extremely rare - if anyone has any of these variations I'd be interested in seeing photographs of them (or even aquiring them if they are spare!).
All INERT etc.
Dave.
The .9" cannon for this cartridge was developed for use as an aircraft cannon. The ordnance department of the United States Army started its development in about 1935.
The T4 was designed by Colt.
The case is based on the 28 X 199/SR (1.1" USN anti aircraft round).
It was never officially adopted and after 1945 it became obsolete.
The practise projectile is painted black with an aluminium dummy fuze.
Headstamp is CAL .90" T4 2536 - F.A.I.E.D.B
Considering its experimental the T4 rounds seem to be surprisingly easy to get hold of (I know where one is for sale if anyone is after one).
T1, T2 and T3 rounds were also produced. The T1 was a heavy weapon with a maximun firing rate of 150rpm. The T2 was supposed to be an improved Oerlikon design but was too heavy and in order to obtain the required rate of fire of 400rpm the cases had to be lubricated. The T3 had a different breech lock from the T2 but its rate of fire was the same. T1,2 and 3 catridges/rounds are extremely rare - if anyone has any of these variations I'd be interested in seeing photographs of them (or even aquiring them if they are spare!).
All INERT etc.
Dave.
