Exactly! I'm no gun expert, but I think I'd be able to figure out the caliber by looking at it.

[That and she plans to tell Mikami about the bullet later. Mikami must have seen the bullets the gunner uses, right? Shelley thinks that the gunner's bullets will be well enough to be compared, and she has good enough memory to remember Top Dollar's bullets' general shape and size]

When one's investigating, anything goes! Even the tiniest details can be meaningful.

[That's what Lottie says]