i recognize the major marks- provisional - inspection, final Black powder, 10Bore/12 muzzle "not for ball"
but does anyone know what the "3" on both ends of the marks represents (the chambers measured 2 11/16 - so common British 2 5/8 short ten)
and the "S.P" on the under rib? some barrel maker's initials? the serial number is preceded by "P S" only on the barrels. I know that SP with a crown was later used to signify a heavy proof.
and the R in a circle?
I am guessing these are maker's marks, not proof house stamps but thought someone here may have seen them before. they are on the underside of a Clabrough hammer gun