Scope mounting holes stripped

Discussion in 'Gunsmithing' started by scasolari, Nov 12, 2019.


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  1. scasolari

    scasolari New Member

    Messages:
    3
    Joined:
    Jan 19, 2015
    So got my new scope today and in a rush to get the Talley rings loctited before work, I stripped the top thread of one of the holes on the rear of the action. It's preventing the rest of the screw from catching and twisting in. If I take the base off, I can thread the screw in no problem. The adjacent screw keeps the base rock solid but it'll ease my head if I have both screwed in.

    So what are my options? I was thinking either a longer screw or drilling the shelf down a little further so the screw catches.
     
  2. elf

    elf Well-Known Member

    Messages:
    163
    Joined:
    Nov 26, 2017
    A gunsmith can chase the threads for you. The best method might be to buy blank bases from Weaver (I think) and have the holes redrilled to another location.
     
    Alibiiv likes this.
  3. livetohunt

    livetohunt Well-Known Member LRH Team Member

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    350
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    Feb 16, 2017
    Or drill and tap to larger screws. Lots of people go to the 8-32's.

    If its only stripped on "the top thread" you might be able to use a longer screw and grind it down to exactly what you need.
     
    Jnm300ultra and Black Hat like this.
  4. Vol1975

    Vol1975 Well-Known Member

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    Feb 6, 2017
    You can do it ur self or take to a gun smith and have both the front and rear screw holes enlarged to the next size hole up. Easy and cheap. Why take a chance. One mistake equals one heartbreak.
     
    Alibiiv likes this.
  5. shortgrass

    shortgrass Well-Known Member

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    Mar 31, 2010
    Be aware that if you up-size the scope mount screw holes to 8-40 (NOT 8-32.) the holes in the mount will need to be adjusted, also. 8-32 is not a gun tap, but bases would need modified for that, also. You just need a 6-48 tap and a longer screw. A gunsmith that just does 'general' work should have both in his shop, or obtain those yourself. The screw should screw in more than just a turn. Thats what stripped the hole, not enough engagement with the tapped hole before you tried to torque it. Taps and screws are available from both MidWayUSA and Brownells. If the package the mounts came in don't have torque specs, they can be found using a 'search' on this forum.
     
    smokepoler and MNbogboy like this.
  6. Jmatt

    Jmatt Member

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    Dec 21, 2018
    I had a similar problem when I tried to install a one piece DNZ rail/rings. Someone had enlarged the holes on the action and tapped them poorly. The hole closest to the barrel in my case could not be through tapped and I could only get two turns on that screw as it was. So I bought an 8-40 bottom tap, an American made bottom tap, as the hardened steel will just ruin a cheap Chinese tap, and now I get 5 full turns. Also retapped the rest of the holes and bought Torx head screws and ground them down to length to achieve maximum thread contact through the top of the receiver. Probably overkill but the entire sighting system of the rifle starts with mounts that don't move!
     
  7. ShtrRdy

    ShtrRdy Well-Known Member

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    Jan 14, 2012
    Sounds like you can have the thread cleaned up on the receiver and screw and it'll be fine.
     
  8. skipglo

    skipglo Well-Known Member LRH Team Member

    Messages:
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    Jan 23, 2015
    Cut a small notch in one screw longitudinal and thread it back into the hole...it will chase the thread and you should be good to go..but you have to buy another screw....

    .