British Ordnance Collectors Network
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30/20mm usn
- Thread starter kahu1
- Start date
Tony Williams
Well-Known Member
Another postwar experimental 20mm US aircraft gun round from my Ammo Photo Gallery, the 20x158RB T5 for the T33 gun. It's shown with some other 20mm experimentals and the 20x110 Hispano for comparison. The two next to it are replicas of WW2 German projects known only from drawings.
Tony Williams
Well-Known Member
It's covered in Chinn, although the emphasis is more on the gun than the ammo (as usual). As I recall, it was dropped in favour of the 20x102 in the race to become the USAF's new standard aircraft ammo. I'll look it up later and see what it says.
Thanks Tony, there must be a huge difference between the 20X102 and the 20X158 in performance and also size of gun, amount of rounds they could carry etc. I really wouldn't want to be on the receiving end of a 20X158.
Dave.
Tony Williams
Well-Known Member
The 20mm T33 gun project was commenced by Oldsmobile in 1944 with the aim of producing a high-velocity gun which would fire shells at 3,500 fps and at a rate of 750 rpm. The design was gas-operated, and apparently based originally on the Rheinmetall MK 103 30mm gun although it was much modified as it went through various versions.
The project was handed over to the Armour Research Foundation in 1946 and development went on until 1952. By the end of the project, a potential production version was estimated to achieve 1,000 rpm with a muzzle velocity of 3,800 fps. Weight 140 lbs and length 83.5 inches. The cartridge was electric-primed and fired a 1,600 grain (104 g) shell. Some 900 grains of propellant were used.
The project was handed over to the Armour Research Foundation in 1946 and development went on until 1952. By the end of the project, a potential production version was estimated to achieve 1,000 rpm with a muzzle velocity of 3,800 fps. Weight 140 lbs and length 83.5 inches. The cartridge was electric-primed and fired a 1,600 grain (104 g) shell. Some 900 grains of propellant were used.
