The brass piece looks like a FLEEM (sp?). Fleems were used as a medial tool for blood letting in the 1800's and earlier. Yours looks like the body without the blades. I won't swear to it but that what it looks like to me.
I think the other 'gun grip' style piece is that of a small handsaw.
I have similar such models in my tool box...
The thin slot where a barrel might go would be for the saw blade I think.