The reason that the T-34 takes so long to load, is because their is no loader in the T34. The Gunner has to do his own loading, or the TC could try to do it for him. But from what I've read, usually the gunner had to lay in, aim, fire, and reload in the early T-34's.
I don't see this being the same problem with the Firefly, as they had a designated loader.