For a crime novel I need an early side by side double in 12 gauge. It should be a good quality older (late 19th or early 20th century) American gun, such as a well-to-do man might have inherited. Because both gun and shell casings have been recovered, it is necessary to be able to describe both accurately and in detail. There are many descriptions of guns on the web, but they don't give the kinds of information that would interest a detective. None I have seen even says what the chambering is, much less whether the shell casings are brass or paper, or whether they are currently available commercial nitro loads. It makes a difference, for example, whether the shell is rare or common, as it affects the detective's ability to trace it.
I am completely dependent on the good will of you experts here, since I can offer nothing in return except my thanks and an honorable mention in a manuscript that may never be published. My limited expertise is in handguns, so I will have to take what you say as gospel.
