Weatherby Mark V standard receiver: Look at hole to hole dimensions below before ordering. Your firearm might be made on a different receiver. Mounts fit right hand firearms. Base screws are 6-48 X 1/4? long and ring screws are 6-40 X 5/8? long. Both screws use a 7/64? Allen wrench. Outside to outside of rings is 4.44?. Standard rings are .63? wide and have 2 ring screws per ring. 4 Hole to hole spacing dimensions are .86? 4.28? .60?. Height of mounts from top of receiver to centerline of scope tube is – low .94? medium 1.06? and high 1.19?.