To lap or not to lop that is the ?

Discussion in 'Long Range Scopes and Other Optics' started by rharfo, Jul 18, 2013.

  1. rharfo

    rharfo Well-Known Member

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    Last year I was in a hurry to shoot my new HS Precision and Swarovski Z5. I didn't lap the lightweight Talley rings. I have an October elk hunt in NM. Should I pull the scope and lap the rings? Is everybody else routinely lapping Talley (one piece lightweight) rings? Rifle shoots 1/2 like its supposed if I do my part.
    Thanks in advance for your thoughts.
     
  2. Ludicrous

    Ludicrous Well-Known Member

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    If the scope has not moved on you and the combo shoots good leave it alone.
     

  3. mtnwrunner

    mtnwrunner Well-Known Member

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    Yeah, what he said.:)

    Randy
     
  4. MudRunner2005

    MudRunner2005 Well-Known Member

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    Couldn't have said it better myself.

    However, unless you're just really OCD, and feel it necessary. Regardless...I wouldn't bother with it.
     
    Last edited: Jul 18, 2013
  5. highridge1

    highridge1 Well-Known Member

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    Leave it , it's already together no reason to take it apart to lap
     
  6. 42769vette

    42769vette Well-Known Member

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    Home run
     
  7. rharfo

    rharfo Well-Known Member

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    I am a bit OCD but will leave it. Good to go! Thanks everbody.
     
  8. bruce_ventura

    bruce_ventura Well-Known Member

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    I would lap those Talley rings for two reasons. First, the Talley rings that I’ve used looked like the ring surfaces were extruded, not machined. I could clearly see the extrusion marks. When I lapped them I could see that they were not perfectly round. Here’s a photo of a pair of Talley rings half way through the lapping process. They’re mounted on a Weatherby MkV. These rings needed to be lapped quite a bit to make the surfaces round. They were aligned fairly well before I started, too.
    Ring Lapping (3)_smc.jpg

    This eccentricity in the rings reduces the surface contact area, or stresses and deforms the scope tube, or both. It can cause the scope to slip, the point of aim to change with temperature, and leave ring marks on the tube. So, to answer the OP's first question, I always lap Talley lightweight rings.

    Second, Swaro Z5 scopes have a parallax adjustment knob on the turret housing that moves a focus lens back and forth inside the scope tube just in front of the turret housing. That’s right where the front ring grabs the tube. You can see the sliding inner lens tube if you look into the objective with a small light. The sliding inner tube must fit precisely inside the scope tube, or else the focus knob will be stiff, the inner tube will bind, or the point of aim will not hold.

    If the front ring is not round, it will deform the scope tube, which can put stress on the sliding lens tube. Now add the effect of shock and recoil. Over time, the parallax adjustment could become worn at the stress points, causing the lens tube to become loose. That could lead to a point of impact that changes with temperature or focus setting, or shot to shot.

    Some of these problems can take a while to become noticeable. All of this can be avoided by lapping the rings.
     
  9. Sully2

    Sully2 Well-Known Member

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    There is no such "requirement" for rings to be "round" on their ID. They can be very oval in shape and still grip the tube of the scope sufficient enough to prevent slippage....thats not to say that "oval" shaped rings WILL do the job.....but they can be out of round and still do as percieved.

    One major scope manufacturer states to NOT lap their brand of rings.

    Tell ya what makes rings go oval and scrape scope tubes....and thats trying to tighten down ring screws to about 50 FOOT POUNDS instead of what they are supposed to be....and then scratching your head when things go haywire