It looks pretty good.
My advice would be this in future attempts.
In the old guns, the rust builds up in recesses, as thats where its hard to whipe.
Scratches happen on places that protrude from the gun.
Usually ill dab into the recesses with a thinned paint, and then whipe clean over it.
It adds a touch of realism that you cant put your finger on.
This looks pretty good however, for a first run at it.