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Minimum clearance between the barrel and scope?

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sanjose View Drop Down
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    Posted: February/12/2011 at 12:12
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!
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sanjose View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sanjose Quote  Post ReplyReply Direct Link To This Post Posted: February/12/2011 at 12:25
to add to it...with the 0.6 m clearance (about a credit card), the scope center height comes to about 1.5 inch. Using medoium rings will make it 3.2 mm higher.
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Kickboxer View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: February/12/2011 at 14:31
There is no "minimum height", just clear the barrel.  I've had to grind down lens covers a couple of times.  Once again, the lens cover must clear the barrel.  I've had clearance so thin a dollar bill would BARELY slide between the bell and the barrel.  Never a problem on a WinMod70 Laredo 7mmSTW with no muzzle brake.  
Welcome to the OT forum...


Edited by Kickboxer - February/12/2011 at 14:36
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SD Dog Quote  Post ReplyReply Direct Link To This Post Posted: February/12/2011 at 14:32
What are you mounting the scope on?  Most of the time as long as the scope is not touching the barrel, you are fine.  Extremely hard kickers can cause scope tubes to flex some.  .6mm is pretty close tolerance but should be fine. 

Moving the scope up 3mm is not much, but you are the determining factor with that.  If it make your check weld uncomfortable, then it is a problem.

Forgot, Welcome to the OT!


Edited by SD Dog - February/12/2011 at 14:33
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Post Options Post Options   Thanks (0) Thanks(0)   Quote dsr Quote  Post ReplyReply Direct Link To This Post Posted: February/12/2011 at 16:21

This video might answer your question.

 
 
enjoy,
 
dsr
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sanjose Quote  Post ReplyReply Direct Link To This Post Posted: February/12/2011 at 16:52
Thanks for the welcome Kickboxer, SD and Dsr!

Appreciate your input and advice!

I am installing this on a sako A7 in 30-06. So does have some recoil.

If the flex is anywhere near as you see in the video, 0.6 mm could be a little too less of clearance. Would also need a very grinding of the lens cap...almost paper thin. The fit is great with the low rings. Not sure of 3.2 mm will make a major difference...I probaly need to just order a the medium rings and try the fit.

Thanks again!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: February/12/2011 at 17:25
Originally posted by dsr dsr wrote:

This video might answer your question.

 
 
enjoy,
 
dsr

,,, if shooting the .50BMG.  Special case...
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Griffin99 Quote  Post ReplyReply Direct Link To This Post Posted: February/12/2011 at 17:41
+1 SD Dog
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kam Fong as Chin Ho Quote  Post ReplyReply Direct Link To This Post Posted: February/13/2011 at 15:03
Is about 5mm "just fine" or kinda "too much" for my general purpose varmint and whitetail rifles?

Sorry, I'm a scope-noob...

Thanks.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Kickboxer Quote  Post ReplyReply Direct Link To This Post Posted: February/13/2011 at 16:41
5mm clearance??  C'mon, let's not get all hung up on this.  5mm is 0.2inches.  No, it is not too much. Some are really uptight about how "tall" the scope sits.  It is all personal preference.  I just happen to have had a rifle/scope combination where the scope bell was REALLY close to the barrel. I shot it that way for years and it has always been under 1/2 MOA.  7mmSTW is not exactly the lightest "kicker" out there.  One of the best gunsmiths I've ever known, armorer for the 1980 U.S. Olympic Shooting Team, mounted the scope... could just barely pass a dollar bill between the scope bell and the barrel.  Even with the sunshade on it, it never "touched".
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jetwrnch Quote  Post ReplyReply Direct Link To This Post Posted: February/14/2011 at 23:37
FWIW, the line of sight measurement from line of bore is more important the further out you're shooting. How much more important I couldn't say. Being able to acquire the sight picture quickly and comfortably may be of more importance. If the stock has a high comb the low rings may cause issues with cheek weld, etc. Just a thought.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Xlr8n Quote  Post ReplyReply Direct Link To This Post Posted: February/15/2011 at 09:53
I agree with  jetwrnch's comment above ^^^ From an accuracy standpoint the closer to the barrel the scope is mounted, the more parallel the scope line of sight and barrel line of sight are which is optimum, but proper cheek to buttstock, and eye level to eyepiece alignment needs to be considered as well.
You're not going to be as accurate if you're crouching your neck or tilting you head to see through the scope.
 
Keep in mind scope clearance becomes more critical with the larger the diameter of the scope objective.
 
If my math is correct, on any given rifle a 3-9x40 scope with 7mm of clearance between the objective bell and barrel would have the same overall crosshair height as a 3-9X50 with 2mm of clearance between the objective bell and barrel.
 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ed Connelly Quote  Post ReplyReply Direct Link To This Post Posted: February/15/2011 at 18:53
If you can slide Obama's brain between the barrel and the scope you're in good shape.....
 
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