When you never ran out of ammo

why are the revolvers more in those moves like an smg

In reality cowboys would modify their guns. Lone Ranger modified his Winchester so whenever he reloaded, it would instantly fire the next shell.

Yeah it's odd

how can there only be room for two of them even though theres room for 2 million rounds?

You mean: 584958484985984985985948548477238499939330494940494900400000959584844732283 rounds