Browning BLR short action: Base screws are 6-48 X 1/4″ long and ring screws are 6-40 X 5/8″ long. Both use 7/64 Allen wrench. Outside to outside of rings is 4.29″. Rings are .63″ wide. 4 Hole to hole spacing dimensions are .50″, 2.81″, .50″. Height of mounts from top of receiver to centerline of scope tube is – low .94″, medium 1.06″, and high 1.19″. Mount fits both left and right hand firearms.