I don´t know, if you all have seen the AMX 13 "Loader".
It´s principally two drums - HAND turned - to the turrets back.
As the turret is oszillating, the drums are always in line to the cannon.
So regardless of round used, the cannon fires, one of the 2 men in the turret rotate manually one of the two drums, and slide the chosen shell into the cannon. In Line.
AMX ( and later Kürassier ) is rather a self propelled gun, than a Tank. More in line with the Marder II / III than a Centurion.
The AMX 13 is the Panther ´s gun on a cheap, quick, agile suspension.
Shooting HE is simply a waste. AP is the intended round.
The kind of shell in the drums and on the way into the gun is totally irrelevant.
Hermann