Thank you. I believe you are very close as this screw measures .131. This screw is for the tenon fitted to the dovetail in the barrel which the forend latches onto. I think it was a half dog screw but sometime in the last 100 plus years the nub has worn away and the screw was damaged by being tightened against the barrel dovetail proper instead of the mortice in said dovetail. I appreciate your response.
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