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Thread: Precision shooting and.......... Your eyes.

  1. #1
    Spartan Elite zfk55's Avatar
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    Precision shooting and.......... Your eyes.

    Not a C&R, but..... As concerns vision, ......This is what happened to Latigo with his Wilson Custom AR10 and an insanely clear and expensive scope...... a Premier Heritage 1,000 yarder.




    She has a custom, internally re-machined Armalite AR10 receiver/magazine well cut to accept a slightly longer AR10 custom magazine, this because of the required OAL.

    All internal receiver areas are coated with a Tungsten Disulfide Matrix derivative. The chamber and throat are cut to accept one projectile profile only. The Sierra 175 MK,

    and no other. Because of these cuts the TTL, seat depth and OAL are specific and critical, thus the need and reason for a custom machined Mag-well.

    Walther 17-4 S/S barrel, internally tapered .006 electro-polished bore and a 1-10 ROT. Moly Specific.

    SWS foregrip and a prototype trigger from his inventory that later evolved into the Chip McCormick trigger.

    The following is the sequence and history of some 1,850 chrono'd and logged in rounds sent downrange, some of which were moa in 5 round groups, but Lat wandered in and out of moa to 2moa week after week. He was getting frustrated. I'll make this as short as I can.

    We used the original Load Data, case prep and the cases themselves were not easy to get. They were to be Lake City headstamped "LR". Those are the USMC Long Range cases that are once fired and collected by a specific case and projectile supplier.



    Prep, shoot... no moa, change the load by 1/10gr increments up and down...... moa once in a while.
    Note the "bell curve" of the weighed brass



    This is what we tried:

    Powder charge change in 1/10gr increments to 2gr under and 2gr over initial data.

    TTL OAL

    Bushing change

    Seat depth changes

    Seat depth and charge changes to 2gr under and 2gr over intial data.... Chrono spread literally tight with the original data, IE: 2505fps. SD +-7

    The above amounted to some 1,800 rounds with one critical change midway through. We found that our Moly process, similar to Sierra's was not deep or hard enough. You should be able to go 7 to 800 rounds without seeing any coppering of the lands/grooves at all. I changed my process to match Stewart's and the coppering after 160 rounds disappeared, but still no consistent moa shooting. Lat was discouraged to say the least. He was about ready to stack it in the armoury and work with his M1 Garand for a while, until..............

    Lat's down prone in the shootshed and I told him I'd been watching his shooting technique all along and judged it solid and correct, but today I had an idea. I had him remove his prescription shooting glasses, put on his contacts and fire 5 rounds. MOA!! We went back to the armoury and reloaded 20 of the original load data we had on day one! 4 moa groups right out of the gate! Back to the armoury for another 20 rounds.........But this time, I had him remove his contacts. Sub-moa! Back for another 10, same results sub-moa!

    So, 1,870 SMK projectiles, pounds of powder, frustration and disappointment was all traced back to something so simple we hadn't considered it. Contacts and prescription shooting glasses. Those contacts did a slight floating action on his lenses and the shooting glasses changed with his prone head position. He could move his head slightly and got a better, sharper picture. That should have told me something, but I never imagined it.

    The Wilson performs exactly as designed, and Latigo is an extremely happy camper. A lot of component dollars lighter.... but happy.
    Last edited by zfk55; 12-05-2017 at 06:37 PM.
    .. An' ole' Brer' Rabbit..he set in de bushes.. he watch an' he wait.. lay low an' don' say nuffin'

  2. #2
    Spartan in Training
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    That's some serious patience, glad he got it sorted out, but I would think most folks would have either thrown more money at it or given up.

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    Spartan Elite SteelHorseCowboy's Avatar
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    In boot camp, our drill instructors had us wrap a boot band around the nose piece of our BCGs. This held them a bit higher on our faces, getting the center of the lenses more centered to our eyeballs.

    Tell Latigo to consider iLasik. Best investment I've ever made for myself. Started with 20/40 on the left, 20/60 on the right, and now my vision is 20/10 in both.
    Don't ever think that because I'm peaceful, that I've forgotten how to be violent.

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    Spartan Elite SteelHorseCowboy's Avatar
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    It's almost annoying actually...
    Found a couple of dead pixels in my computer screen.
    Don't ever think that because I'm peaceful, that I've forgotten how to be violent.

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    Shooting prone,It is very easy for prescription glasses & contacts to alter the sight process through optics.
    I'm glad I can't shoot prone anymore,my body can't take the stress it puts on my joints anymore.

  6. #6
    Spartan Elite SteelHorseCowboy's Avatar
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    Yep. Even contacts have a contour to them that affects light passing through. Well, we all probably know that's how they correct your vision, what I mean is that it can do weird things at odd angles.

    I prefer not to even wear safety glasses when I shoot, just because of this. I do it anyway though.
    Don't ever think that because I'm peaceful, that I've forgotten how to be violent.

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