Hello,

I have this revolver, SN 107XXX (mine is blue):

Smith & Wesson 32 Double Action Fourth Model Revolver
The National Firearms Museum: Smith & Wesson 32 Double Action Fourth Model Revolver

The cylinder spins freely when the hammer is down. Is this normal operation?

The cylinder seems to lock up correctly when the hammer is cocked.

Thanks

This is definitely not normal. You may just need to clean the insides and inner workings or you may need to replace something like the cylinder stop, or its spring, or the plunger or screw that bear on the spring. This is a five screw gun, and the fifth screw (into the frame in the front of the trigger guard) is the area in question. See blow-up pictures for an early K-frame, they are essentially the same.

Froggie