I had issues with one of my ROAs doing the exact same thing, found 2 issues, the half cock notch was cut too deep, and the hand was short by approximately .005. Added material to the hand and dressed it back to where it needed to be and removed a small amount from the front of the half cock notch. The short hand was the bulk of the problem. While I was fiddling with all this I also added a small amount of metal to the back of the bolt where it meets the hammer plunger and corrected when the bolt drops, it was dropping halfway between the locking notches. Its now dropping into the front of the lead cuts. When the revolver is cocked there is one click at full cock. It does this for all 6 chambers.