Art touches on it, but there are two things to remember:
1. You want the optic to clear the rifle: a manufacture's catalog or inquirey (perhaps e-mail to Savage or Springfield Armory) will tell you this.
2. When you mount the rifle with the butt to your cheek in a consistant manner that can only come with practice, the center of the sight should be at the center of your eye. You don't want to have to hunt around for the sight. This is actually a function of the stocking of your rifle. Rifle stocks today are made for a mythical average man who will mount a scope on his rifle. But sometimes a little higher than normal scope mount will actually bring a particular rifle's scope up to a better position in regards to the eye.
It is obvious, if you understand this, that no rifle stock could actually ever be made that is ideal for all scope objective sizes. So it is worth playing around with the mounts at first.
If you cannot play with them personally before buying, get the recommended mount for the scope. If you need to go a little higher, you can try a higher moun later. But if you need to go lower, you have a stock problem, which is more complicated.
Try
www.springfeild-armory.com for information, since it's their scope.
[This message has been edited by Herodotus (edited September 01, 2000).]