Wouldn't that be counter-intuitive? In a mortar, it's the rebound socket and breech plug that 'work' against the recoil forces generated by the expanding gasses of burning increments, and in a gun it's the breech, recoil mechanism and trails that do the work. The muzzle just happens to be there, providing some final guidance but without exerting itself.
Now, perhaps in the days you are referring to, it was the end of the barrel where
you worked, with sponge and rammer. ;D