[The demonstration of the gun furthers his interest in it, the portion of the barrel — if it's even called a barrel, being so square — sliding as he'd thought, but leaving him wondering exactly how it all comes together to fire.]

If I'm not to find shot balls and gunpowder easily, what is it you use for ammunition?

[Are they that outdated they're to be mocked? It's likely, and he's more curious about it than anything. Noting the way Wash leans forward and regards his own weapon, D'Artagnan sets it down and attempts to look pointedly at the man, but he's missing the sight-line of the camera again.]

I might be inclined to let you handle my pistol if you'd advise me on trying something new.