[Kip Russell]

Shop owner needs to go shopping:

I've never had one of those magazines, but I've read they can be unreliable, and in any case are heavy and bulky.

If you really need a lot of shots without reloading, I'd go with a 60-round Surefire. Not that much larger than than a 30-round PMAG (see picture).

[Pollster1]

True, but the drum is more photogenic.