[NoAlibi]

Is there a rule of thumb that will let you know what height rings (Low-Medium-High) will accommodate which size objective lens of the scope you're putting on your rifle?

[Red State]

Well, obviously this can vary significantly from gun to gun, but in my experience:

Low rings work for scopes with objective lenses of 28-32mm

Medium rings work for scopes with objective lenses of 38-44mm

High rings work for scopes with objective lenses of 50mm

[JDGray]

Depends on the base your using. Best to choose a base, set your scope on it, and go from there. I just installed a VXIII, 30mm tube, 50mm objective, and set the scope on the base with .040" clearance. I couldn't get low enough rings:)

If your scope has no clearance, stack coins under it to get the right height, measure the stack, and buy a set of rings accordingly.

[NoAlibi]

Thanks guys, now I have something to guesstimate with.

One more question please - Is the ring heigth measured from the base to the center of the ring, the bottom or the top?

[JDGray]

Is the ring heigth measured from the base to the center of the ring, the bottom or the top?

Top of the scope base, to the bottom of the tube. If your using a 1 piece weaver base, the stack of coins will represent the thickness of rings you will need. Midway has a very good ring selection, with the heights listed, use them as a reference for height and p#, then Google the part number. You'll probably find them cheaper, but Midway has taken a bunch of my money over the years:)

[NoAlibi]

JDGray - Thanks for the answer.

I don't remember when I first hooked up with Midway, but they got a bunch of my money too. There was a time when you went to them first, but lately the good deals have been few and far between. Some of their so-called "sales" are laughable - discounting 30 cents off a $35 item. So I don't mind using their resources and then pricing it out on other sites.

[DRYHUMOR]

Some makers use what they call a "standard" height, it usually clears a 50mm scope.

Sako rings sit on high bases, the mediums will clear a 56mm scope in most cases.

The barrel contour and length of the scope come into play also, along with how far forward or backward it has to be mounted for the eye relief.