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Posted: 8/9/2006 6:53:35 AM EDT
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One of my recent builds is having an extreem windage problem. The rear sight (a Troy flip up BUIS) is nearly all the way to the right and the gun is still shooting a little left at 50 yards. My EOTech is also adjusted quite a bit to the right. If the extreem adjustment were only required in the rear sight and not the EOTech, I would guess that the front sight was canted a bit and that barrel just needed to be adjusted. Since the EOTech is also requiring adjustment, could the upper have a problem? The parts in question include an LMT take-off upper with an Operator barrel from Denny. |
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Clamp your rifle under your but on a chair or in an upper vise block if you have one. Insert a cheater bar (large screwdriver, wrench etc... whatever fits) through the FSB from the right side. Twist slowly to move the FSB left. The barrel is rotating in the receiver when it actually moves. You should feel a distinct POP when it finally moves. Stop right there. Go zero it again. You can also use the leather/rubber mallet method, but that's less controlled. |
I understand how that will work for the iron sights. In fact, I was thinking about doing that very thing tonight. However, I'm left with a few questions...
My biggest concern is that both the EOTech and BUIS required the windage adjustment. I primary concern that I have a problem w/my LMT upper reciever. Is that a possibility? If so, How could I diagnose that? |
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If you have the Eotech cranked over as well, it's time to pull the barrel and check the barrel socket and mating barrel extension lip. Either the barrel is bent, the mating surface of the upper socket lip to barrel extension has something between it (in a single spot to cause a cant), or you warped the upper receiver when tightening the barrel. Bottom line is the tech is looking down the upper receiver centerline, and the centerline of the bore should be on the same line as well (read sights can be mis-indexed over the bore, but the barrel bore should be centerlined with the upper to begin with). |
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