My eyes were first drawn to the holster. An old crossdraw design that was copied (successfully) up through the 80's, at least.
I picked up a New/Old Stock example from an online vendor who specializes in finding old leather. Mine was made by Earl Ginn company, a small leather maker shop I used to patronize as a young cop. He was located in the South SF Bay Area city of Belmont. Many agencies used him for their duty gear, and he did repairs/modifications of other leather gear.
I still have some of my old leather gear from those days, made by him, and I wanted to get the New/Old Stock crossdraw holster that was from his shop.
I have more than half a dozen J's that work with this holster, but this pic was taken using one of my 642-1's.
The crossdraw design's belt tunnel (wider on one side) allowed for the holster to be tipped within a range of angle to suit the wearer.
As far as using the 50's vintage Cobra? Why not, presuming it remains in good working order. If it were me, I'd stick with standard pressure .38SPL, though. No reason to stress such a nice old example of Colt's revolver heydays.
I have a not-quite-so-old snub, front a short production S&W made using an older revision of the 37 Airweight. Produced as a DAO model for a canceled overseas police contract, using an older frame before MIM and some of the newer metallurgy was incorporated. I'll never use +P in it (after discussing it with some people at the factory, as an armorer). I carry it, and run it for range quals/drills, using some assorted standard pressure loads I've come to favor. As a last resort, I'd not feel ill-equipped using standard pressure 158gr LSWC, but would really try to avoid RNL.
Nice Colt.
