Nobody makes bases to fit as many guns as Weaver. Yet each base is machined to tight tolerances for a custom fit. They're designed to fight the effects of recoil with a square cut notch that precisely mates to the sturdy cross bolt in every Weaver Detachable Ring. Custom hardened fastening screws come with every Weaver base.

No.39 mount

Fits:
Ithaca Lightning X3, front or rear
Colt Cotlsman .223, .243, .308 round receivers, front or rear

Note:
This is only a single mount. You will need to order two mounts for mounting a scope.