Explain Windage Adjustable Bases

Discussion in 'Long Range Scopes and Other Optics' started by mtngun, Apr 18, 2011.

  1. mtngun

    mtngun Well-Known Member

    Messages:
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    Mar 12, 2011
    I'm researching rings and bases and lacking a clear explanation (I've searched this and other long range/sniper sites) thought I'd be safe asking this question regarding scope mounting and windage centering.
    Scope needs to be mounted left to right centered over the rifle bore to insure there is no crossing of the barrel and scope centerline axis. If there is a crossing the scope will be "on" at a single yardage.
    How can I insure the tapped reciever, base and rings will all be accurately machined or designed? There are 6 connecting points where misalignment may be introduced.
    I see usoptics has addressed this by offering rings that incorporate windage adjustment to center the scope.
    Other ring manufacturers offer matched sets of rings and close tolerance rails.
    Is one risking mis-alignment by mix-matching ring and rail manufacturers?
    I see some manufacturers offer one piece rail/ring assy. I do not want to go that route.
    Lacking a good gunsmith I believe I will settle on a base/ringset from a quality manufacturer that specs close tolerance/matched sets. Doing so seems to me will solve the problem of mis-alignment in the scope to ring and ring to base junction.
    I would need to verify proper alignment of the optical center of the scope to the centerline of the screw holes through the base into the reciever and the centerline of the bore.
    I'm aware of plumb alignment and have that figured out. My goal is to know my alignment is good so that I can develop accurate charts for distance/windage/coriolis-spin-drift.
    I know one is at the mercy of the manufacturers or a good gunsmith. The proof will be apparent when I get this all purchased/set-up and test fire my 200-100-500 yard rounds. I don't want to be unpleasantly surprised.
     
  2. 436

    436 Well-Known Member

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    Mar 22, 2009
    I think your thinking over kill on the rings and mount question... If you want to split your adjustments into fractions; buy a base with a friction windage screw; like Leupold Std's otherwise you'd have to use a friction windage adjustment on your scope... Optional
    When using a windage capable mount.. Count your scopes "windage click’s" then divide the number by 2 and click back to that number... That's the mechanical center of the scopes adjustment. Put the scope into your rings on the adjustable windage mount; center the reticle "up and down' with the drop line {make sure your drop line is in your bore view cutting the center of the bore in half left to right in the bore} using the adjustments in the mount make sure the reticle and bore are centered on the drop line..... Here’s some other things you can try in centering up your project.


    There are many ways to set up ring's, mount and scope.


    Scope Alingment .223

    Good luck
    436
     

  3. mtngun

    mtngun Well-Known Member

    Messages:
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    Mar 12, 2011
    I tend to overthink these things (anal engineer). I want to get the best alignment possible right off.
    I briefly looked at a couple of topics in your attached link. Thank you for providing those.
    Being unfamiliar with some of the brands offering rings and mounts I felt I'd be taking a leap of faith in going with "any" set (matched or not) of base and ring.
    I could assume that all manufactures accurately machine all aspects of their products. Knowing how much is outsourced now days I rather be sure.
     
  4. 436

    436 Well-Known Member

    Messages:
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    Mar 22, 2009
    Sure I understand, start with Leupold USA; there are others; but for what you want to do I think they'll work just fine for you.
    Good Luck
    436
     
  5. topgun736

    topgun736 Member

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    Jul 19, 2010
    Lets talk about cold hard facts.There are no perfectly straight barrels and yes the factory drilled holes in the receiver may not be in line with the bore axis,that is why if we all buy the same rifle,rings,mount, and scope, chances are that the windage and elevation will be different on all of them when they are sighted in at the same range. Windage adjustable bases are an exellent idea,they are still being produced by several manufacturers and were designed to overcome these problems.Also purchase a bore sight collimator not for zeroing but to check your scopes performance. and to find the center of the scopes windage and elevation travel.Once you have done this move the base screws to zero the the rifle as you are sighting in off the bench. then do your fine tune with the windage knob. Yes I'm probbably given myself away here which is ok. I have built and serviced thousands of scopes in my shop for over twenty years, and we continually have scopes come into the shop with the windage knob turned all the way to the right or the left where the gunner behind the gun has turned that knob untill it stopped and then turned it even more untill they popped off the turret or pinned the iverter tube to the inside of the main tube wall.in some cases they have broken the inverter spring. the original Denver Redfields have the least travel in the varriable modles. The original Elpasso Weavers have alot more travel,but the one I have checked that has the most in a present day scope off the shelf is a Leatherwood Hi-Lux.