H&r 999 da

[A1armorer]

The revolver works in S/A; the sear sets in the hammer notch when pulled rearward and squeezing the trigger enables the hammer to fall and the gun fires.
However, in D/A, the hammer does not rotate rearward far enough to engage the D/A sear. And while the trigger is held the hammer can be rotated rearward and the sear is set; then squeezing the trigger the hammer will fall.

Is the rearward rotation of the the hammer a function of the lifter?

I will sure appreciate the help.

[376Steyr]

If it was mine, the first thing I would do would be to pull the grips off and soak the entire gun in solvent, then flush the innards with still more solvent, and then see if it wanted to work. My experience with older guns is the trigger assemblies are often choked with old solidified oil. Sometimes a good cleaning is all that is needed. Numrich Gun parts company has a good exploded schematic view posted online, if you absolutely feel you need to take it apart.

http://www.gunpartscorp.com/Manufacturers/HarringtonRichardson-33274/Revolvers-36449/999-38120.htm?page=5

[Thumbcocker]

That was the unofficial revolver of every teen aged boy in Southern Illinois back in the day.