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Posted: 1/16/2005 1:54:57 AM EDT
| Read the FAQ regarding this topic and wanted opinions before having to send two weapons back. Went to the Horandy 75gr TAP as our duty and swithced out one bushmaster 14.5 1/9 with a bushmaster 14.5 1/7. Excessive elevation problem of approximately 18 inches with iron sights and optics. I doubted putting a taller front sight post would fix problem. Sent it back to bushmaster. Problem was resolved, but they claim too much torque was used on the barrel nut and replaced FSP with a taller one. For irons I guess I would have to buy into that explanation, but we changed out two more BM 14.5 1/9 to BM 14.5 1/7 barrels using just 40 torque to line up barrel nut and have the same problems. Can someone explain how a taller FSP would resolve the optic problem? Can we try something else before having send two weapons back? |
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Measure the height of the FSB from the center of the bore to the top of the "UP" marked flat and compare it to the original FSB. Been seeing this is a lot with recent BFI barrels, I'm wondering if they changed their FSB dim. Last excuse I got from them was that the taper pins were too tight. 
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| I'm no engineer and I'm trying to understand how the elevation got so out of wack for the aimpoint and agoc compac. The optics are mounted to the flat top and the irons are not being used as a reference. Their adjustment is to the extreme in order to zero. Why does the elevation change so drastically when all we did was change twist rate? I might have already went on this rant when the first barrel was changed a few months ago. Sorry if this is a repeat. Thx Tweak |
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interesting, you just gave me a piece of the puzzle, I missed where you said that they were off EL wise with optics on the flattop. since all you changed was the barrel then the barrels are probable goofy. something along the lines of how the barrel extension mounts to the barrel or how it fits the upper. maybe concentricity. if torque throws a barrel out of alignment (it doesn't) the throw would be random, not uniformly down, I think they are using crappy barrel extensions, seeing any accellerated wear on the bolt lugs? |
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