How much clearance between scope and barrel?

[sanjose]

Changing the scope rings to a Warne Maxima fixed.
With the low rings the minimum clearance between the barrel and objective is only about 0.6mm.
That does not leave room for the flip covers that came with the scope. But I can alsways shave the bottom, or use the bikini type.
If I get the medium height one, it will be about 3.2 mm higher giving a total of 3.8 mm clearance.

Is there a minimum amount of clearance that one should have to accommodate for barrel flex etc?

Secondly does 3.2 mm make material difference?

Thanks for your comments!

[GeoffLinder]

The lower clearance is fine as far as things go. 1/2mm clearance is way more than the flex in these components (better not be much at all). Lower is usually better when it comes to mounting a scope BUT 3.8mm is not a big difference in eye position so that may be the better way to go so you can use the flip-ups you want to use and not have to futz with things :-)

The most important factor here is whether the scope sits at the height your eye sits at when your cheek is in place on the stock comb. Barrel clearance means nothing in comparison to this fit point as long as the scope doesn't actually touch the barrel

[r3dn3ck]

Pulling the scope higher off the gun will have an effect on your mid-range trajectory in that the bullet's flight path above line of sight is greater the higher your scope is mounted and the further you place your far zero. What all that translates to would be that you may be hitting much higher than you think at ranges inside your zero range.

I have seen this with a couple of my guns and the net effect was that (using an exaggerated example here) if I zero'd at 200yrds, then at 100yrds the bullet was 5" high and I had to know pretty closely how far the target was and how big it was or I could easily be outside point-blank range and have to hold a little low for really close shots.

[Fjold]

Close your eyes, shoulder the gun, then open your eyes and see where your eye lines up.

[sanjose]

Thanks guys!

I agree that a higher clearance will make a diffrernce in target sighting at different ranges. I am not abke to figure out how much difference 3.2 mm additional will make.

How much extra clearance did you have in the gun you used in your example above?

[GeoffLinder]

Thanks guys!

I agree that a higher clearance will make a diffrernce in target sighting at different ranges. I am not abke to figure out how much difference 3.2 mm additional will make.

This is NOT an important thing and nothing to worry about. 3.2mm will NOT have a difference that matters or that you can even measure.

Example 1: 135gr .270 bullet at 2740fps. 2.5" center of scope to center of bore height offset. Zero at 250 yards = 3.18" high at 150 yards

Example 2: 135gr .270 bullet at 2740fps. 3.5" center of scope to center of bore height offset. Zero at 250 yards = 2.78" high at 150 yards

So as you can see, a 1" difference in scope to bore height and all that changes in mid trajectory is a 4/10 of an inch decrease in the 150 yard rise point.

As I said, nothing to worry about :-)

[Divernhunter]

First of all mount the scope as low as you can. Then if it is a hunting rifle throw away the stupid flip-up scope caps. IF you use them and hunt long enough they will cost you an animal. It will be a snap shot and you will not be able to get the caps open etc and still shoot. Carry a lens pen if you are concerned about the lens getting dirty. Use a leupold scope and you will not have to worry about any other weather conditions and such.

[beauregard]

Close your eyes, shoulder the gun, then open your eyes and see where your eye lines up.

Holy crap, that's awesome. Thanks for the tip.

[sanjose]

Thanks all!

GeoffLinder, that makes sense. I too tried the ballastics app for a difference in scope height of 1/8 inch and there really is no difference. Appreciate your looking this up!

Fjold, Tried that and the fit is OK. Don't know if 3 mm will make a difference in fit. Thinking of going with GeoffLinder's advice and ordering the medium rings. That will be the best way to try for fit.

Also had posted this question on opticstalk and someone pointed to tis video. Sounds like there could be some flex. I am using this on a 30-06 Sako which has decent recoil.

http://www.youtube.com/watch?v=s5pVya7eask

Thanks again!

[GeoffLinder]

Fjold, Tried that and the fit is OK. Don't know if 3 mm will make a difference in fit. Thinking of going with GeoffLinder's advice and ordering the medium rings. That will be the best way to try for fit.

http://www.youtube.com/watch?v=s5pVya7eask

Thanks again!

3mm will not be a worrisome thing on eye fit. If you find the scope a tad high for your cheek weld, a cheek piece adapter can raise your eye position to what is needed.

[Nessal]

I think people put TOO much emphasis on getting the scope as long as possible. You should shoulder the rifle and then see where your natural position is. You will shoot better being comfortable rather than trying to force your head as low as possible on the rifle.