S&W #4 .32 break action revolver

[boot strap jack]

Just picked this up today, it is missing some nickel. I was wanting to know if these function like a modern double action, IE.. single or double, or just double? This revolver seems to be double action only. Sometimes the hammer may stay cocked if drawn single action, most of the time it drops on releasing it. On times that it does stay cocked, if you put a little pressure on the hammer she will drop. The action locks up tight, and shoots in double action just fine, just a long, long, long trigger pull. So what are the ideas out there? I did open it up and everything appears to be fine.
BSJ

[boot strap jack]

I did a lot of looking for a model 4 s&w on the wire, none found. I did find a S&W 32 DA model #4. This is what I have. S&W made the 32 DA and 38 DA, the first on a frame of the 1 1/2 size. The second is on the #2 size frame. Mine is 32 DA 4th model of that gun. Also I did find out these were able to fire single and double action. After finding this out, I opened it up again and finally foundb the sear notch on the hammer. This notch had been stoned almost off the hammer. I think someone thought it was a burr on the hammer, not realizing that this was the single action sears notch. At first looking at the insides the double action part of the action looks to handle all task. Numrick arms list a new hammer, but out of stock. Now I need to hunt down my needle files and try to cut the notch in it again.
BSJ