Weaver ring to base fit

[abbydad]

I recently installed a Weaver #63B base onto which I tried to fit (previously used by someone else) Weaver #49044 and Weaver #49047 rings. Both sets were supplied with "quick detach" "square cross bolt" fittings. Neither ring would take up tightly on the base. I then tried (new) Weaver #49164 rings (same style fittings) and they fit fine. Could (today's) Weaver base have different a cross section from one made several years ago; or, could the used ring's lower half have "stretched in width" from previous tightenings? Gremlins?

 

[brcman]

Abbydad, I just went through the exact same thing while setting up a rifle for my grandson. They have changes something just a little so one cannot mix old rings with new bases.