hand stop
Is it a 40X or 40XB, barrel size has nothing to do with the model ?
Are you referring to the base or the handstop? No such thing as stop plate.
For 40X #19793 for the swivil base and #19798 for the swivel block.
For the 40XB #15820 for the rail and #15824 for the swivil block.
bjm