The gloss black Top Mount Base #57 from Weaver has been machined to tight tolerances for a custom fit. This aluminum base offers maximum strength so that the rings will hold tight.
The Winchester 52 may require bolt and/or safety alterations, otherwise the firearm will not function safely and properly. Consult with a qualified gunsmith.
To pinpoint the correct base for the Winchester 52 Rifle check the spacing of the tapped holes for the rear base and compare it to the hole spacing for the front base. If the hole spacing is the same use 46+ 46. If the hole spacing is different use 25+ 57.