How wide are Weaver scope base recoil grooves, really?

[beatledog7]

I recently acquired a used bolt action rifle with scope bases and rings in place. The rings are about .53", and the scope I want to mount has an objective bell diameter of 48mm, so I only need about .24" or .25" rings. Using the existing rings will place the scope about .28" too high, so they have to come off.

I got one off, but the other has been tightened so hard I've buggered up the torx screw heads. So there's a trip to the gunsmith or to Lowes' for an easy out. The bases, which I assume to be Weaver-style, are fine: no reason to change them.

That aside, I have what should not be a mystery but has become one. Shopping for lower rings online made me second guess what kind of bases these are. My research says the recoil groove in a standard weaver rail/base is .18" wide, but these bases have grooves that are just .148" wide. (The lug on the ring I got off measures .145".) I found that odd, so I went to another supposedly Weaver base (factory rail on my Buckmark Hunter), and it's grooves also measure .148"

Am I nuts, or are the specs I'm finding all hosed up? Or maybe these bases are not Weaver. So then, what kind of bases have recoil grooves that are .148" wide?

 

[beatledog7]

Update: The second ring is off. Bases are Weaver 47s, just as they should be, but I'm left with the groove width mystery. Gonna order low rings, Weaver-style Millet windage-adjustable Angle-Locs, just like the high ones that came off. They have to fit.

 

[esque]

I measured two different Weaver bases,
both measured .144"

 

[beatledog7]

Hard to believe nobody else wanted to chime in here. I was sure the answer would pop up in a few minutes.

 

[dprice3844444]

sears makes a nice easy out also

 

[ApacheCoTodd]

Supposed to be .180 but I'm not certain on the tolerance span.