Correctly mounting a scope on a rifle

Discussion in 'Long Range Scopes and Other Optics' started by peterb, Jun 16, 2009.

  1. peterb

    peterb Active Member

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    I have been putting scopes on rifles for about 40 years. This is not to say that I have it right, and now that I am shooting further than 300 yards, thought I would throw this in and get some advice. (Previous threads have been a brilliant learning experience !)
    I normally mount the scope on the rifle, then sitting back a little, take an imaginary line through the vertical cross hair extended down to the centre of the bolt (as viewed from the rear.) My .223 and .308 both have Lynx mounts which can be adjusted to enable scope alignment.
    This, by the way, is before you actually start dialling turrets.

    Can anybody tell me if this is the correct method, or is there a better way to ensure alignment from the start ? (We gotta keep it simple !)

    I tried a bore sighter years ago without much success and it was that exercise that led me to discover my current method.

    Cheers,

    Pete.
     
  2. CAM

    CAM Well-Known Member

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    peterb

    I'm no expert, but one way to line up the cross is to drop a plumbbob on a colored string, level your action and then look at the string from 100m or what ever distance you want. works very well to get the cross straight with the action.
    If it is a pricey scope I always lap the rings.

    Cam
     
    Last edited: Jun 16, 2009

  3. jimbires

    jimbires Well-Known Member

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  4. peterb

    peterb Active Member

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    Thanks guys.

    I had actually watched a demo video on the Horus Vision site and that was much the same as you two have suggested.
    With Lynx mounts, you actually have an allen screw on each side of the vertical mount to tighten it onto the small poles which come up from base mount . Depending on how you tighten these screws dictates how the scope aligns with the rifle. I can literally have the scope sitting at about 5 degrees off alignment with the bore of the rifle. I can also have it sitting parallel to the bore, but not necessarily vertically over it.
    That is what I am trying to resolve.
    Short of measuring their position with a vernier, I can only use the visual appraisal method and want to know if that is sufficiently accurate.

    Cheers,
    Pete.
     
  5. MontanaRifleman

    MontanaRifleman Well-Known Member

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    That's a good article, and I would use Cam's method first, the shoot the plumb line to confirm the alignment. When mounting the scope I would place the rifle as close to the plumb line as I could and still focus the scope on it. Then look through the bore and align it so it splits the bore as well as you can with your eye. Then adjust the widage knob until the reticle aligns with the plumb bob. This should get you extremely close if not dead on. Not only should this get you perpendicular to the scope but it should also get your windage very close to zero.

    Just my $.02

    -MR
     
  6. peterb

    peterb Active Member

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    Thanks MR. I will be doing just that.
    Pray tell, good sir, do you know if the scope is not seated close to aligned, does the reticle movement actually straighten it out for accurate all range shooting ?

    Cheers,

    Pete
     
  7. HUAINAMACHERO

    HUAINAMACHERO Well-Known Member

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    Pete,
    I asked the same question months ago, and I got very interesting answers. A fine and very rich discussion developed between members on how to do it better. I learned a lot reading it. Give it a look, it might help you.
    The thread is called: Leveling your scope, look for it through the search option.
    Hope it helps.
     
    Last edited: Jul 24, 2009
  8. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Pete,

    I have actually never mounted a scope like this. The last time my scope was mounted, it was moutnted by the guys at store where I bought both my rifle and NF scope. They used a couple of different levels and a scope zero tool and did a fair job (I watched the whole process). The next time I mount a scope, which should be fairly soon, I will do it just like I described to you.

    Not sure what you mean by "seated close to alinged"? Here are my thoughts on it... the closer you can get your bore to the plumbline, the less error you might incur by eyeballing the plumbline's disection of the bore. i.e., if your muzzle was right up against the plumb line, you would have virtually no error in plumbing the center of your bore. If you could focaus your scope enough to adequately see the plumbline to this close distance you could extremely close to aligning your windage reticle to the center of your bore, if not dead on. You would also plumb the reticle in the process, making it perpendicular to the bore.

    When doing the shooting test. I would fire at least 3 shots on zero and 3 shots at 20 MOA (or more) high, to make sure that if there is a descrepency, it is not the single bullet which might be a little off.

    Hope this helps,

    -MR
     
    Last edited: Jun 17, 2009
  9. woods

    woods Well-Known Member

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    After years and many different ways of mounting a scope I have settled on this way for the last couple of years

    Get and EXD thingamabob

    BROWNELLS: EXD ENGINEERING VERTICAL RETICLE INSTRUMENT: EXD ENGINEERING

    which is very well made and mine checked out perfectly level
    [​IMG]
    [​IMG]

    The twin V-notches center it on your rifle barrel and your scope
    [​IMG]

    this will align the bore and the scope while the rifle is in a vise. When the bubble is level then the rifle is completely uncanted.

    Next while the rifle is still in the vise aim it out the door at a distant level object; 4' level on a fence, weighted rope hanging from a tree or the edge of a building you have verified level (for instance). With the EXD bubble level, rotate the scope in the rings until the reticle is level with the distant object. Now you have to tighten the rings with the EXD level and the reticle level which is not an easy thing to do but can be done with a lot of patience.

    That will level the reticle and I have yet to level one this way and get to the range and feel like it is a little off. That happened quite often with the shoulder-it/adjust-it, shoulder-it/adjust-it method.

    Now that you have the reticle level when the rifle is uncanted it is important to be able to duplicate that in the field. The best anti-cant device I have found is the ScopLevel

    Scoplevel Anti Cant Leveling Device

    that will fold down when not in use and is visible without loosing your cheek weld on the stock
    [​IMG]
    [​IMG]

    FWIW
     
  10. peterb

    peterb Active Member

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    Collectively, your blood is worth bottling.

    MR, the issue I have is that with the Lynx mounts, it is possible to move the scope mounts sideways at right angles to the rifle bore. This then can put the scope out of vertical alignment with the bore, but still aligned if you get my drift.
    However, Woodsy has just given me something to do. Even though I am a farmer, I actually do quite a bit of machining and welding of aluminium from time to time. The device he has sent me pictures of is not hard to make and is really clever. Took a few secs to work it out, but that will solve the above problem as I explained.
    I have also been doing a little more research around the site as you suggested and once again am beginning to get a good grasp on how all this comes together.
    I actually got hold of my spirirt level yesterday which has a laser in the end with the ability to give a flat knife edge beam. I used it to check the scope and found it as near as damnit to bang on. Shooting will give me the final answer.
    Tremendous, Thanks guys,

    Cheers,
    Pete.
     
  11. MontanaRifleman

    MontanaRifleman Well-Known Member

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    Pete,

    That is an ingenious looking contraption. Why didn't I think of it and get it patented?:rolleyes:

    Since I dont have access to a machine shop, and if I did I think I would do more damage than good, I will do it with the plumb line.

    Keep us posted on your progress and results, and I will do the same.

    Cheers,

    -MR
     
  12. peterb

    peterb Active Member

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    Okay, the weather down here has been absolutely diabolical,strong winds, wild rain storms and a decent wind chill factor.
    lightbulbFunny I was relegated to the shed this arvo. Took me about 3/4 of an hour to make the backing plate and the small section which sits on the scope. made it from 6mm x 100mm flat ali plate. Could not find a small string spirit level, so used a mammoth spirit level instead.
    Would you believe the thing actually works !!
    If you are at all handy, I think two pieces of 1" x 1/2" with a piece welded (or bolted ) across the top and bottom holding them together but with a slot gap for the bolt to run would also work. All you would have to do is to place the two 1"x 1/2"pieces back to back and cut them at an angle to get the 'v' to fit the barrel.
    But then again, if the device is only a few bob, why worry. As for me, I have never seen anything like that in my life, and the real satisfaction in all of this is making something like this and then having it work right through to the final outcome which is being able to confidently hit the target -if you're good enough !
    Not good to be so enthusiastic though, I am in the early stages of buying a 12 - 42 x 56 night force scope with Mildot reticle. Not the NXS as they are way beyond my reach, and besides, I don't think I can honestly shoot well enough to be able to justify one of those.
    (They do cost over here!)

    Great outcome once again,

    Cheers,

    Pete.