Re: Show Some Grit, Perhaps?
A steam gun was what the 'constables' on the island of Rish were using, though no one actually saw one in action.
It's a standard looking gun, slightly larger than a pistol, with a second hand grip to the front. It's powered by steam rather than explosive powder. The gun is connected via hose to a canister worn on the back.
That was all anyone could determine visually.