Leveling the Scope Reticle for Long Range Rifles

Discussion in 'Technical Articles - Discussion' started by ADMIN, Jan 21, 2013.

  1. ADMIN

    ADMIN Administrator

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    This is a thread for discussion of the article, Leveling the Scope Reticle for Long Range Rifles, By Bruce Winker. Here you can ask questions or make comments about the article.
     
  2. ba19500

    ba19500 Well-Known Member

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    I recently bought a Wheeler professional scope leveler. If this thing really does get it level, and the shot is left or right of center 20" higher, then I am wondering if by turning the scope tube, I am just canting it which is defeating my purpose. How good are these units?
     

  3. bruce_ventura

    bruce_ventura Well-Known Member

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    The Wheeler product does a really good job of aligning the turret to a flat horizontal surface on the receiver. This is a variation of method 5 in the article. It's great for short range, but susceptible to rifle manufacturing and alignment errors at long range.
     
  4. walkin

    walkin Member

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    If the scope is offset, like say on a win 30-30, the crosshairs would be canted so the verticle axis would go through the center of the bore, I'm guessing you would need to hold the gun with the verticle axis of the crosshairs plumb when shooting, with the gun canted?
     
  5. bruce_ventura

    bruce_ventura Well-Known Member

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    Walkin, in theory that's correct. In practice, 30-30 is not a long range cartridge. Even if the reticle alignment is off, canting errors will be small at ranges up to 300 yds. Only by pushing the cartridge to 500 yds will canting errors become significant (six inches or more).
     
  6. walkin

    walkin Member

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    Bruce,I was basically trying to use that as an extreme example to get it straight in my head . Going to try out the ring true,sako trgs 30-378 and a 257 wby mag vangaurd.

    Thanks for the reply
     
  7. Len Backus

    Len Backus Administrator Staff Member

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    I must confess that since I was busy lately I had not read this article carefully until this morning. Very impressive. I feel it is THE definitive article on reticle leveling anywhere out there. Nice job!

    And I just bought one of your Ring True Alignment Tools.
     
  8. Wile E Coyote

    Wile E Coyote Well-Known Member

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    Yesterday, I received a 'Ring True Alignment Tool' in the mail. That was fast - 2 days from CA to NY.

    This norning I used the tool to check 2 scopes. The first rifle/scope is several years old and has been tested and trued the hard way - by shooting and dialing elevation then adjusting. I know this rifle is dead on. If I followed the directions correctly, the Ring True confirms what I already knew.

    The second rifle has a new scope that I mounted this past week for my nephew . The reticle was leveled by eye and checked by sighting on a cable holding a bird feeder about 75 yards out the back window. It was bore sighted by eye and a couple rounds fired to know it is on paper and very close at 100Y. NO! I didn't shoot the bird feeder. Anyhow, this was to be my starting point for the next trip to the range, knowing this setup would need to be tweaked. According to the Ring True tool, I'm canted to the left by a small amount.

    For the sake of science, I'm going to leave the rifle alone until I have the opportuinity to shoot a few rounds as is; probably next weekend. First check how out of plumb my eyeballs are then I'll use the Ring True to re-setup the scope as per the instructions.

    If there is anything substantial to report, I'll do so here in a week or so. Then I'll make an appointment with the eye doc.


    Pete
     
  9. Triple BB

    Triple BB Well-Known Member

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    Great info and a great article. I purchased a B-Square cross hair alignment tool a few weeks ago, but haven't used it yet on my custom build. My intent is to verify the scope is level and in alignment. I initially used method 5 to set everything up. Question for Mr. Bruce. I have a custom rifle build with everything being trued and squared at least per my smith. If I verify alignment with the B Square tool, I assume it would be fairly simple then to further fine tune it via the live fire method hopefully using only a handful of shots? Any suggestions. Thanks...
     
  10. bruce_ventura

    bruce_ventura Well-Known Member

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    Triple BB,

    For a trued action and a straight barrel, you should be within 2-3 degrees using that tool. You'll know for sure when you do the live fire test.

    You need to fire at least six rounds to determine the center of two groups. If you need to change the reticle alignment, then you should repeat the test (six rounds) because your point of aim may have shifted. Ammo costs can add up using this method.
     
  11. kermodie

    kermodie Active Member

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    Good read, however there is a misprint in the live fire method.

    "If the second group falls to the left or right of center, the scope should be rotated clockwise or counter clockwise respectively" - should read, if the second group falls to the left or right of center the scope should be rotated (counter clockwise or clockwise) repectively. The upper reticle line should be rotated toward the deviation, same effect as the shoot one hole and adjust the reticle to the hole method of alignment.
     
  12. rick523

    rick523 Well-Known Member

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    Now I'm confused,if group falls to left why would you rotate it counter clockwise, or towards the group? :cool:
     
  13. bruce_ventura

    bruce_ventura Well-Known Member

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    It would not surprise me to have gotten this wrong, because these discussions are often counter-intuitove. Tonight I worked through this problem two different ways and got the same result. I believe the article is correct as written.

    Take Fig 2.B in the article, for example. Bullet impacts fall to the right of the plumb line. This aiming error can be corrected - for this elevation setting only - by moving the aim point to the right by the same offset.

    Which way do you rotate the scope to correct the aiming error for all elevation settings? Recall that 24 MOA of elevation adjustment have been added to the reticle to get the bullets to land so high on the target. The aim point is still down at the lower impact point (bottom of the figure). The rifle bore and the scope tube rotation axis are both pointed up at the second impact point (top of the figure). Therefore, rotating the scope counter-clockwise in the rings will swing the aim point to the right, because the aim point is below the axis of rotation. And that's what the article says you should do.
     
  14. DocB

    DocB Well-Known Member

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    Good Morning Sir,

    From your very informative and educational article I gather that you are not a fan of laser borsights and favor an "old school" optical collimator, which is fine with me because I'm an 'old school' kind of guy.:)

    I am interested though in your views as to why an optical collimator is preferable to a laser boresighter.

    Again, thank you for a very well written and enlightening article. I will be visiting your store quite soon for the Ring True Alignment Tool as well.

    Doc