Ron was glad, at least, that Harry had shut the door. Although he wasn't happy about having to explain the gun to Harry, it would probably be easier than explaining it to Hermione . . . or to Harry and Hermione.
"It's . . . insurance." Realizing that wasn't the clearest explanation, Ron added. "Harry, you know some of the people I deal with aren't exactly on the up and up. And Muggles, well, you point a wand at them, they're not liable to realize you mean business, yeah?"
He hoped that would be enough to satisfy Harry, even if he also doubted it, because Ron his best mate, and the last thing he wanted was Harry beating himself up over the risks Ron had to take when it came to keeping them all alive.