Screw broke on scope base

Discussion in 'Technical Questions & Information' started by mtwehn, Nov 5, 2009.

  1. mtwehn

    mtwehn New Member

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    Nov 5, 2009
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    3
    Looking for advice/opinions on the following.

    the rifle is a remington Model 760. Holding the rifle the hole with the broken screw is nearest to the butt of the rifle. The other three holes for the scope base are fine. I want to mount a Leupold base and rings on the rifle. The Leupold base is a single piece so all 4 screws attach the base to the rifle. the front 3 screws are pefectly fine.

    I broke off the screw head with a torque gun removing the old base last night :mad:. When removing the base the other three screws came out with minimal effot, then the 4th broke. Dont know what kind of base it was but it was mounted in 30 years ago.

    My question:
    Would you attmept to drill and use a screw extractor and possibly have to retap the hole or will the three good screws hold the base? Given its a single base I am believe the three screws will hold throuhout the years. Thouhts?
  2. zb338

    zb338 New Member

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    Recently moved to Pennsylvania.
    Take it to a good gunsmith. It will be worth the few
    bucks he will charge you.

    Zeke
  3. Helix_FR

    Helix_FR Active Member

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    Imperial, MO
    I would not attempt yourself unless you have experience in doing it. Screw extractors are great for larger screw bases but the tiny ones just don't work that well. Most times they too break off in the hole you created, then you got yourself a real mess b/c now you have a piece of hardend steel in the middle of a broken screw.
    Drilling a broken mount screw is also hard to do unless you have a mill or a drill press with 1/1000 run out on the head. Also using left handed drill bits can save you the grief of having to retap the hole. I had situations were while drilling the broken screw backs itself out. Chances are that the broken screw is not broken perfectly flat so any hole that you start with such a small bit will walk out of the hole and ruin the receiver. You have to go slow with very minimal speed and usually these speeds are slower than any drill press can turn. (i start any broken screw heads at about 50 rpm most drill presses are 500 minimum)
    So here is an option. Soak that broken screw in some penetrating oil for about a day. Take a punch and lightly tap occasionaly to break up any corrosion that may be binding it. Get a hardend small flat blade screw driver (one that is small than the hole) and tap that into the broken screw making a score in the broken screw. Then try to start turning it out. It may also help to turn and tap at the same time. This is were a gun vise is very handy. If you can get to the bottom of the screws by disassembling the gun that will help some b/c now you can turn a different direction if CCW doesen't work . Do not turn CW if the gun is still assembled, you can ruin parts real quick if your not careful and potentially bind the action.

    Good luck, If in doubt take it to a smith, its not that expensive and its worth saving that scope.
    My worry on the scope mount with 3 screws is depending on caliber the shock from that unscrewed end will ruin the scope and also put more stress on the 3 remaining screws which can cause those remaining to strip themselves.
    Last edited: Nov 5, 2009
  4. mtwehn

    mtwehn New Member

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    the gun is a .270. I have experience with taping holes and removing screws but Ive never done anything so small. My tap and die kit dont even have a 4-40 or 5-40 set. I am thinking a gunsmith is the correct route
  5. Suicide*Ride

    Suicide*Ride New Member

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    If there's some screw threads above the hole, file or grind the end flat & then use a paper thin grinding wheel (Dremel) to cut a slot like a regular flathead. Don't forget to use some penatrating oil before trying to turn it. If it's broken flush, I'd disassemble the rifle, & drill the screw out from the inside of the reciever, using a drill bit that's the same size as the hole or using a sharp (new), ball burr & a Dremel motor.

    Good luck if you do it yourself, & welcome to TFF!

    SR :)
    Last edited: Nov 5, 2009
  6. mtwehn

    mtwehn New Member

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    I took it to a Smith. It broke off clean with no threads showing. Thanks for the welcome and I appreciate everyones response.
  7. langenc

    langenc Member

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    Oct 23, 2009
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    Montmorency Co, MI
    If you are goint to mount the scope forget the loctite. A drop of fingernail polish is adequate for most rifles, except perhaps some loudenboomers.

    Clean the screws and holes w/ oil remover first-scope and mounts. Never had one come loose.
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