Does anyone know what the radius of the rear bridge on a Winchester model 70 is? I need to build a sight base and have no easy way of measuring the radius. No optical comparator around here.

There is a formula in the Machinery's handbook on how to measure it. It is fairly easy with a mill and dial indicator.

Jim

Yeah I was hoping someone knew it off the top of there head so I wouldn't have to do that. I probably have it written down in one of my old gunsmithing books but finding it might take a long time. Push come to shove I may measure it that way.

One of the gunsmithing books has the radii of all Weaver mount bases.

My old notes show a 1.340" raduis for the rear bridge of the M70's

Thanks that sounds about right.

OH the joy of the internet. I looked for base spec and found I could print the whole chart on weaver bases right off of Brownells site. Its called W.R. Weaver Company Mount Base Specifications. Thought some of you might like to have this also.

Thanks!