I think some of you imagine this to be a lot faster than it is. There's a good delay before a holstered weapon is reloaded, and if it turns out that delay isn't long enough, we can always increase it. This shouldn't be usable for cheating out of a reload; this should be for switching to another weapon, using it for a bit, and then switching back to your reloaded initial weapon.
It's still really powerful! But I wanted to jump in before everyone thinks this is instant or whatever.