Own one, ridiculously fun, to quote my father "it's the only gun I've ever shot that makes me giggle". It holds more than 10 rounds of .22 short and has wooden barrel shroud, making it an evil assault rifle to some (which I find a minor plus). Gets regular stares at gun ranges and occasional "I'll let you shoot mine if you let me shoot yours"
To reload you pull the plunger out of the magazine tube and drop bullets down the tube. the tube's located directly below the barrel (and the barrel extends about 1/4 of an inch beyond the tube) so you wouldn't be able to top up without yanking the suppressor. You might be able to get a few rounds in if you shorten the mag tube and cut a slot in the side to drop the rounds in.
If you do end up attaching a can, post pics. Nothing like making my favorate useless gun even more joyously useless.