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Thread: Be cautious with optics screws

  1. #1

    Be cautious with optics screws

    Last year, when I was working with Leupold on the Delta Point Pro, they were testing a Pro on their accelerated testing machine, and broke the two screws holding the optic to the fixture. Today, my wife was checking zero on a C More RTS 2 mounted to a 320 Legion, using a Springer Precision plate, when the zero seemed to move three inches. We looked at the optic and realized not one but BOTH screws attaching the C More to the Springer plate had sheared. We had recently mounted this optic to replace a defective Romeo 3 Max and had reused the Springer screws. Pictures below.

    Moral of the story is to not reuse screws when replacing an optic, as they are a potential weak link. The sheared screws ruined the Springer plate, but that is better than if the optic was direct milled, and they sheared in the slide.

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    Likes pretty much everything in every caliber.

  2. #2
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    So replace screws every time you change batteries?

  3. #3
    Member Alpha Sierra's Avatar
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    Quote Originally Posted by GJM View Post
    Last year, when I was working with Leupold on the Delta Point Pro, they were testing a Pro on their accelerated testing machine, and broke the two screws holding the optic to the fixture. Today, my wife was checking zero on a C More RTS 2 mounted to a 320 Legion, using a Springer Precision plate, when the zero seemed to move three inches. We looked at the optic and realized not one but BOTH screws attaching the C More to the Springer plate had sheared. We had recently mounted this optic to replace a defective Romeo 3 Max and had reused the Springer screws. Pictures below.

    Moral of the story is to not reuse screws when replacing an optic, as they are a potential weak link. The sheared screws ruined the Springer plate, but that is better than if the optic was direct milled, and they sheared in the slide.

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    How many tightening cycles did the screws on Leupold's test rig have? Those on your wife's pistol?

    How tightly does the sight on your wife's pistol fit into the mount?

    The CZ mounting plate on my gun needed some clearance on the front lip to let an RMR go in, and even then if the sight wasn't almost perfectly plumb it would jam on the recoil studs, that's how little clearance there is on that setup.
    Last edited by Alpha Sierra; 01-20-2020 at 06:16 PM.

  4. #4
    Member MVS's Avatar
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    I have not broken any screws. Just a couple of days ago I did strip the head out of one trying to take a defective RMR on my Gen 5-19.

  5. #5
    What was the torque on those screws? I have been using a vortex wrench to torque to 12 lbs.

  6. #6
    Old man yelling at cloud OlongJohnson's Avatar
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    Are they quality grade 12.9 screws (like those made by YFS in free Taiwan)? Or the finest Chinesium from the mainland?
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    Not another dime.

  7. #7
    I donít how many cycles the DP Pro screws had, but it was being endurance tested on a special machine. It is interesting that the screws were the weak link for that test scenario.

    I believe there were four cycles on the screws that broke today. I called Springer and they were very helpful. They asked me to remove the plate and check the screw length, and it turns out the screws were about a thread or so too long protruding below the plate, preventing optimal tightness, and allowing vibration which led to the shearing. They have another replacement plate and screws on the way too me already.

    Long term, I wish the industry could standardize on a footprint like the Acro, and direct mill slides, so we could eliminate multiple failure points for shearing and stripping screws. I do think using fresh screws is a good approach when changing optics.
    Likes pretty much everything in every caliber.

  8. #8
    Member NickDrak's Avatar
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    Any idea on the manufacturer of the screws? Lots of Taiwan (YFS) screws out there in the pistol mounted optics universe.

  9. #9
    Quote Originally Posted by NickDrak View Post
    Any idea on the manufacturer of the screws? Lots of Taiwan (YFS) screws out there in the pistol mounted optics universe.
    Will ask Springer the next time I speak with them.
    Likes pretty much everything in every caliber.

  10. #10
    Member Alpha Sierra's Avatar
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    Quote Originally Posted by GJM View Post
    I donít how many cycles the DP Pro screws had, but it was being endurance tested on a special machine. It is interesting that the screws were the weak link for that test scenario.
    They had to have failed in tension, rather than shear, unless there were no recoil bosses/studs in whatever setup they were testing

    Quote Originally Posted by GJM View Post
    I believe there were four cycles on the screws that broke today. I called Springer and they were very helpful. They asked me to remove the plate and check the screw length, and it turns out the screws were about a thread or so too long protruding below the plate, preventing optimal tightness, and allowing vibration which led to the shearing. They have another replacement plate and screws on the way too me already.
    I kinda agree with you. Four cycles seems a lot to ask of such skinny screws (6-32?). Without knowing more about their metallurgy all one can do is err on the side of caution.

    If your wife's optic's screws were too long, the only way they would not have developed enough joint tension is if they were bottoming out on something solid (like on the slide).

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