I had one a few months ago with the same problem. With block in battery (unloaded), do you have to push the lever underneath to work the slide? If not, then the block is not going to battery completely.
The problem was that the trigger mechanism was not thinking the block was in battery, but close enough to allow the hammer to work. Had to work on all parts to get it to work correctly. (Worn trigger assembly to new block.)
The dog was not allowing the hammer to go full stroke and gave light hits on the .22 rim.
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