They used clips, not magazines, inserted from the top, and the clips would have been ready to go, so it wouldn't have been too big a deal to go around the array stuffing the cartridges in.
There were probably no such arrays with magazine loaders, since they needed access from the bottom.
Both would jam occasionally too, and you would clear jams from the top, so the top-loading C-96 was the right choice.
The C-96 also used smaller caliber, higher velocity cartridges (than, say, the Luger LP 08), better at punching holes in engine blocks etc.
- Bill