Marlin 1894 1895 336 XLR: Will also fit Henry Rifles that are completely flat on top of receiver and are drilled and tapped.Mount fits both left and right hand firearms.Base screws are 8-40 X 1/4a ^2 long. Ring screws are 6-40 X 5/8a ^2 long. Base screws use a 9/64a ^2 Allen wrench and ring screws use a 7/64a ^2 Allen wrench.Outside to outside of rings is 4.08a ^2. Standard rings are .63a ^2 wide and have 2 screws per ring. 6 Hole to hole spacing dimensions are .50a ^2 1.88a ^2 .50a ^2 .37a ^2 .50a ^2. Mount has 6 holes thru it so it can be used on the long and short receiver. 2 holes will not be used. Depends on the gun to what 4 will be used. Height of mount from top of receiver to centerline of scope tube is - medium 1.06a ^2 high 1.19a ^2.