Muzzleloader
Modern mortars use a shell with the propelling charge and primer attached at the base.  Unlike older muzzleloading mortars, which were loaded the same way as muzzleloading cannon, the modern mortar is fired by dropping the shell down the barrel. A pin at the bottom fires the primer, which then ignites the main propelling charge.  Both the modern mortar and the older mortar were used for high angle fire.  However, since the mortar is not loaded in separate steps makes its definition as a muzzleloader a matter of opinion. However, in the simplest terms it does load from the muzzle end.