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  1. #1
    Join Date
    Oct 2008
    Posts
    3,665

    Default Williams FP-SW Rear Sight

    My Williams Gunsight catalog lists a FP-SW for the M11. Am I correct in presuming it attaches to the two grooves milled into the top of the M11 receiver and therefore will not attach to an unmodified K31?

  2. #2
    Join Date
    Dec 1969
    Location
    Northern Virginia
    Posts
    211

    Default

    The Williams FP sight screws to the left side of the receiver. It is not a “clamp-on”: you will need to have the receiver drilled and tapped. The Williams FP-SW uses the same base that is used for the Model 70 Winchester … 70AP, but with a longer windage slide. Casual observation will show you that the 1911 series receiver is not cylindrical like the Model 70, the Schmidt-Rubin tapers from rear to front. The base of the FP-SW is “close” , but it really does not fit the 1911 receiver without some grinding to get the base to fit the taper of the Swiss receiver. If you don’t do this fitting, the gallows arm will not be perpendicular to axis of the bore. It’s not off by much, and some folks who shoot only casually may not even notice it. If you shoot with a small rear aperture, the aperture will appear as a “cat’s eye” instead of round because of the misalignment. Again, that may not bother some folks. I’m just picky.

    If you look at the receiver for the K31, you’ll see that the bridge (back part of it) is not round at all, it is sort of a rounded inverted trapezoid. To mount a Williams FP-SW on a K31, you’ll have to do some serious grinding on the sight base to get the base to fit properly, and I would recommend also bedding it to the receiver with Marine Tex. Yes, I’ve done it … about ten years ago when I first decided to shoot my first K31 over the National Match Course. I used it for one season and then replaced it with a Redfield base for the International Sight. I have since replaced the Redfield International sight on that rifle with a John Wilkes sight, which fits the same base, has much more elevation and windage adjustment. The Wilkes sight is the grand-daddy of today’s RPA “Tracker” sight.

    If you want a click-adjustable receiver sight for a K31, and you are not a“serious competitor” or you think you can’t afford the excellent clamp-on Swiss Products sights, the Williams is a worthwhile choice, but it’s not going to be inexpensive, either. The basic sight with screw driver adjustments is about $73, the sight with Target knobs is about $85, and add to that about $9 for the thumbscrew for the elevation slide lock, unless you want to be fumbling around for a small screwdriver every time you need to make an elevation change (even with the target knobs). So you’re close to $100 already just for parts. Add whatever the cost to do the drilling and tapping and fitting, if you’re not equipped to do that yourself.

    Resp'y,
    Bob S.
    USN Distinguished Marksman No. O-067

  3. #3
    Join Date
    Oct 2008
    Posts
    3,665

    Default

    Quote Originally Posted by BobS View Post
    The Williams FP sight screws to the left side of the receiver. It is not a “clamp-on”: you will need to have the receiver drilled and tapped. The Williams FP-SW uses the same base that is used for the Model 70 Winchester … 70AP, but with a longer windage slide. Casual observation will show you that the 1911 series receiver is not cylindrical like the Model 70, the Schmidt-Rubin tapers from rear to front. The base of the FP-SW is “close” , but it really does not fit the 1911 receiver without some grinding to get the base to fit the taper of the Swiss receiver. If you don’t do this fitting, the gallows arm will not be perpendicular to axis of the bore. It’s not off by much, and some folks who shoot only casually may not even notice it. If you shoot with a small rear aperture, the aperture will appear as a “cat’s eye” instead of round because of the misalignment. Again, that may not bother some folks. I’m just picky.
    Thank you. That lets me know this is not worth pursuing.

  4. #4
    Join Date
    Dec 1969
    Posts
    113

    Default Sights

    Leon-I think that you are starting to be on the path that leads to what is real and not the path to what might be (however desirable but not realistic).Target or sorta target sights will all ways come at a price!!!Will

  5. #5
    Join Date
    Oct 2008
    Posts
    3,665

    Default

    Quote Originally Posted by Will Durant View Post
    Leon-I think that you are starting to be on the path that leads to what is real and not the path to what might be (however desirable but not realistic).Target or sorta target sights will all ways come at a price!!!Will
    I was curious about how the Williams FP-SW was mounted. An e-bay vendor described one as mounting without gunsmithing, so I got curious. The only dumb question is the one not asked.

    As I mentioned in a different post, the Swiss Products diopter option was a factor in my decision to buy a K31.

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