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Posted: 12/9/2010 9:14:56 AM EDT
| I have a bushmater patrolmans carbine and about a year ago I had the upper changed over to a flattop. I recently was give a set of rails from my cousin. I put them on my riflwe and noticed that the front sight base does not line up with the rail. There is a a little over a quarter of an inch that is not in line. I did notice that the rifle was shooting to the left also and the the direction the sight needs to move is to the right. This would make me think the base is canted. I will put up some pics later this afternoon. I donot know who made the rails but they are not free float and hve 4 screws that hold them together. |
| Sounds like the barrel canted a little bit when the upper was assembled. The barrel nut is tightened clockwise on the reciever, if the indexing slot/pin are a little off then the fsb cants a little bit to the left. You can leave it, it won't hurt anything as long as it's shooting straight. Or get the tools and redo it. |
| I looked inn the chamber and the feed ramps are matched up and flush so I think the barrel was put back on correctly. I do not think the front sight base was removed the pins do not look like they have been hammered on at all. The rails may be out of spec. That may be why I was given them anyway I think I will just take them off. They are really bulky and make the rifle heavier. As far as the rifle shooting to the right I think I will just go back and zero it again like we used to do before we went to the range to qual. I have an LMT rear sight so I have room for windage adjustment. |
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'shooting to the left also and the the direction the sight needs to move is to the right'
Don't forget, the front sight goes opposite the direction you want the POI to move, so the more right it goes the more left the POI goes. See if you can sight it in with a reasonable adjustment of the rear sight - if you can, there's no problem with the barrel/sight. |
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You will need to find a gunsmith to adjust your barrel.
Or It's not too difficult to do if you want to adjust it yourself. The barrel and rail might need to come off, then the barrel is turned and then re-tightened. If the alignment pin is against the stop, then you need to file the slot wider, to gain the necessary adjustment needed when indexing and rotating the barrel. Do a search and look in the FAQ areas to understand what is needed and how the barrel connects on your gun. |
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Quoted: 'shooting to the left also and the the direction the sight needs to move is to the right' Don't forget, the front sight goes opposite the direction you want the POI to move, so the more right it goes the more left the POI goes. See if you can sight it in with a reasonable adjustment of the rear sight - if you can, there's no problem with the barrel/sight. This. As long as your rear sight isn't completely left or completely right and still not zeroed, you should be fine. |
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Quoted:
You will need to find a gunsmith to adjust your barrel. Or It's not too difficult to do if you want to adjust it yourself. The barrel and rail might need to come off, then the barrel is turned and then re-tightened. If the alignment pin is against the stop, then you need to file the slot wider, to gain the necessary adjustment needed when indexing and rotating the barrel. Do a search and look in the FAQ areas to understand what is needed and how the barrel connects on your gun. Doing this will misalign the gas tube. Bending the gas tube to try to align it will pull it away from its proper engagement point with the gas key. If the FSB is in fact canted, the barrel is pretty much FUBAR. For the amount of gunsmithing work it will cost to correct the problem, he would be better off getting a new barrel altogether. A decent chrome lined barrel with FSB can be had for $200-$250. The barrel could still be sold off cheap though to offset the cost of the new barrel - just make full disclosure that the FSB is canted. OP - You should be able to see if your FSB is in alignment with the stock hanguards currently on the gun. The flat part along the top of the hanguards shouls line up evenly with the FSB and the upper receiver rail (remove the carry handle or sights so you can eyeball along the top of the rail). If ypu are still in doubtHave a gunsmith check the FSB for proper alignment. If it is true, then turn your attention to the rails. The rails of the hanguard should line up with the rails of the upper receiver, if they aren't, then something is wrong with the handguard. You could try to see if the rretaining ring behind the FSB can be rotated at all - it will rortate a little, but not much. This might help. If the rails seem like they are poor quality and heavy, it is very possible that you have a cheap set of airsoft rails. Either way, you would be better off getting rid of them. Decent quality rails can be had for around $150 (like the Daniel Defense EZ CAR). I would rather use A2 handguards than a cheap set of quad rails on my carbine. At best, the sight is in alignment and you leave your rifle as is with it costing you nothing. At worst, you will need to invest around $150 to either get a good set of rails, or replace your barrel (assuming you can sell off the old assembly for around $100). Just my 2 cents. |
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