A very strange British gun

[CutlassCollector]

Originally Posted by fernando

But this doesn't tell us how the grenade was thrown away from the barrel ... or does it ?
Certainly not like nowadays, in that they use a bulletless cartridge containing propellant gas !

I guess the gun was charged with powder into the first section smaller diameter of the barrel and then the stem of the grenade/missile is designed to match the larger diameter of the barrel and is pushed right down on top of the charge.
Marcus's post 3 gives a good impression.

CC