17 pounder anti-tank gun

[Tony Smith]

I think another reason the 3.7"AA was not used as an anti-tank weapon was the non-availability of any armour piercing projectiles, either of the solid shot type of any of the various shaped charge AP types. Mike Calnan might be able to elaborate here on this.
As far as I know, there were only two projectiles for the 3.7", a HE bursting round and a HE shrapnel round.