Possibly Sports Match?
Nope it appears these are a set ofAlloy BSA scope master mounts for 30mm scope tube will fit 9.3 to 13mm dovetails. see through high rings..
One is threaded to accept a recoil stud as shown. Dovetail seems to be 10mm or 11mm
They came on a used scope I brought. The stud was not fitted. The allen headed screws take a 7/64th key
£12:00 posted within UK