I have a Model 64-6 snub firing pin in frame that is DAO and the hammer catches at about 1/4 to 1/3 of the travel to the rear. It can be pulled through and is not very noticable when the trigger is pulled quickly. I tried pulling the hammer by hand without using the trigger with the cylinder both closed and opened. No bind or catch using that method. Backing off on the strain screw can just about eleminate the catch but I know that is not a fix. I don't think the hammer is rubbing the frame. Oiled the heck out of it. Still no joy. Just got it today didn't notice this problem in my pre buy inspection as it is DAO. Any help is appreciated. Thanks

I would take of the side plate and look for burrs. Maybe around the trigger return slide area or the slide itself, or a stud boss, maybe look for a line forming on trigger or hammer. Try it with the hammer block piece out, they sometimes have a rough spot or the corners of the "flag" piece hang up a bit. I have never seen a real bad seer surface, but, it could happen.

Another possibility would be that the DA sear is improperly fit (short) or worn, and the DA cam on the hammer is striking the corresponding cam on the trigger during the hand off from the sear to this interface.
With this condition, during the trigger pull, instead of a smooth rearward travel, the shooter will feel a "bump" about midway back.

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Ret. LE, FA Instr, S&W Armorer

Pull the grips and see if the rebound slide is hitting the main spring. There were some Wolff springs that didn't have the right curve and would sometimes interfere, one of them may have found it's way into your gun.

Pulled the grips. Rebound slide not hitting main spring. Trying to find my correct screwdriver to pull the side plate.

OK got the side plate off. Didn't see any lines forming or signs of a burr. Put side plate back on with hammer block left out. No change at all. I could disassemble further when I have more time available. Thanks for all the advice so far.

Armorer could well be right. The little DA toggle like piece on the hammer engages the trigger then does a hand off from it to the hammer itself. If that isn't just right it can cause a hitch. Best let someone who knows what they are doing take care of it. I went through 2 of them learning when I got a new trigger for my 396, bobbed it and installed. This is one of the places where the difference between just right and messed up is very small. Pulling the hammer itself back means that that piece is never engaged. Never thought of that.

You talked me into taking it to my trusted gunsmith in Bradford Ohio. I think you are right with your advice. Thanks so much to all who replied. This forum is great.

My gunsmith confirmed this tonight. I'll let him fix it. Thanks so much for your advice.