Scope mounting issue

Discussion in 'AR15/10 Rifles' started by banjoman, Jan 4, 2013.

  1. banjoman

    banjoman Member

    Feb 2, 2009
    Finally got a scope for my RRA ATH. A Nikon Coyote special. The problem I have is there is not enough vertical adjustment to get the scope zeroed. I've heard of people "shimming" the scope to get it closer. Never had to do this before. Is it possible? If so How do I do it?

    Oh an the mount is a RRA high rise scope mount. Thanks in advance for any help
  2. Bullet bumper

    Bullet bumper Well-Known Member

    May 20, 2009
    Shiming mounts is not a good idea it can be done but it tends to bend things .
    A much better solution is a tapered base.
    I presume the Rock River mount is on Weaver or Picatinny rail.
    If it is a removeable rail , then it can be replaced with a tapered rail say 15 or 20 MOA taper .
    If the rail is intergral and I think it may be on an ATH and can't be removed then the next best option is a new mount with the taper built into the mount like ARMS
    MSP Variable Eye Relief Scope Mount and 30mm Rings with MOA: MSP Scope Mounts
    This mount has 3 heights of rings and lots of ring spacing and eye relief options plus choice of 15 , 20 , 25 and 30 MOA taper .
    Also you can buy a set of ring inserts for mounting 1 inch scope tubes in the 30 mm rings .
    Works best on a rail that is right on specs. However if it's to tight and will not lock up teh locking claw can be gently hand lapped witha stone until it locks tightly . If it's too loose you have a problem and the loose protection plate between the claw and the rail taper will need the outside surface to be built up with a steel shim glued inplace with epoxy .
    This is generally not a problem with commercial made rails.
    I would contact Rock River and ask them if the rail will take an ARMS QD mount , it should.
    Another option is aska local gunshop to get you one on the proviso that it fits the rail nicely . Tight by hand .
    This would also be another option and would fit out of spec rails
    Last edited: Jan 4, 2013

    FEENIX Well-Known Member

    Dec 20, 2008
    Instead of shimming, have you considered the Burris Signature Zee Rings with offset inserts ...

    Scopes - rifle scopes, handgun scopes, hunting scopes by Burris Optics

    Last edited by a moderator: Sep 8, 2018
  4. threejones

    threejones Well-Known Member

    Oct 15, 2010
    Might just be a bad mount. I'd check it against another one of the same kind first.
  5. shortgrass

    shortgrass Well-Known Member

    Mar 31, 2010
    Turn the mount around , and see what happens.
  6. notajeep

    notajeep Well-Known Member

    Dec 22, 2011
    I'm guessing in the last two weeks you've got it figured out. If not just FYI you may consider a mount and or rings with 20 MOA built into it. I've got a 20MOA one piece mount on my M-700 and with a 200yd zero I can dial my vertical adjustment all day. IT's like buying that extra insurance on a rental. Most folks don't need it, but when you do it sure is nice to have.

    My mount and ring experience with my M-700, Short action, Left handed was a real PIA. Those mounts are not easy to find, and cost was somewhere near $100 just for the mount. As for an AR-15, I'm in the middle of building one and don't plan to purchase optics and mount till spring. Good luck
  7. banjoman

    banjoman Member

    Feb 2, 2009
    Thanks for all the input guys. I purchased a Burris PEPR mount and all is well.