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Posted: 6/19/2007 5:25:45 AM EDT
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There were a few posts on here in the past dealing with adjusting a barrel with a canted front sight. I searched but could not come up with anything. I just bought a used AR with this problem. It zero's but the rear sight is all the way right with only 2 clicks to spare. And you can actually see the front sight is out of alignment. The procedure had something to do with hitting the front sight with a leather mallet while the upper receiver was in a vice. Any help is appreciated. |
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Vise not needed, but since this is a used upper, you need a benchmark to really start. With the upper shot gunned open, take a good look at the center point of the feed ramps against the centerline of the front take down lug. If the two are centered together, then the leather mallet strikes against the FSB just above the barrel while holding only the upper receiver it's self will allow the entire barrel to slip in the upper barrel socket for the needed new index. Also, keep in mind that this center points may be off a bit, and if the direction that you are slipping the barrel will more true these two points, the better. Short of pulling the barrel to confirm that the barrel extension pin and the gas port/FSB are on the same index plain, you will have to check it via the center points given above. The reason that I bring this up is that there are some nightmare barrels floating around that the FSB's where not installed correctly (FSB/extension pin not on the same plain), and the barrel may already be maxed indexed already in a semi attempt to band-aid the problem. (Barrel lugs to the bolt alignment already to the point that they may be rubbing at lockup/release, and more barrel rotation not even allowing the bolt to enter the barrel ). |
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