Quote:
Originally Posted by chrisgrove
Post war in UK, the 3.7 inch ordnance was used for the 32 pounder towed AT gun (and for the Tortoise).
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Not quite. The ammo for the 3.7" AA and 32 pdr was different, so needed a different barrel to fit.
And of course there were two very different types of 3.7" AA - the Mk 6 was much bigger than the Mks 1-3 guns and used larger cartridge cases for a much higher velocity.
So there were three cartridges used in the same calibre, none of them interchangeable:
3.7" AA Mks 1-3: 94 x 675R with 135mm rim diameter (12.7 kg shell fired at 790 m/s)
3.7" AA Mk 6: 94 x 857R, rim 150mm (12.7 kg shell fired at 1,040 m/s)
32 pdr AT: 94 x 909R, rim 141mm (14.5 kg shot fired at 878 m/s).
See:
http://quarryhs.co.uk/ammotable10.html