I was specifically thinking of the T148E1 grenade launcher however it is/was a semi automatic firing a 40mm projectile however you could in theory own and shoot a 2 Bore single shot shotgun that was within the 12"/24" ruling or in other words a 12" smooth bore barrel with a minimum length of not less than 24". You could use it to shoot slug and less than lethal projectiles which would give hours of fun and keep things vaguely steady by using shortened cases however the real problem is justification. How do you explain to your FEO that you 'need' a 33,6mm diameter short barrel shotgun, alternatively there is always the gurlie lightweight 4 Bore 26,7mm offering.
Anyone fancy owning/shooting something that looks bit like this?
Great fun to shot, accurate and fascinating to actually to see the grenade in flight. I'd love one even if it was a 2 bore. 