Not all jc higgins model 50 have this hole spacing - Warne Maxima Steel Rifle-Scope Base - 2 piece base for J.C. Higgins, Mauser FN .860 RHS

I purchased this base for my JC Higgins Model 50. Apparently, not all of these rifles were set up with the same configuration. My rifle has a rear hole spacing of .500, not .860. My fault, I should have measured first.

Other than not fitting, this base seems to be of good quality.