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Posted: 5/17/2005 10:08:29 AM EDT
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Well, I just put a rail on my midlength and when i look down the sights, it looks like the front sight base is slightly to the right instead of straight up and down. I did take it off to install the rail, but i don't think I made it cant like it is. Could I have done something in my disassembly installation to have caused it to cant to the right or was it always like this and i just never noticed it before? How do manufacturers ensure the FSB is straight? Is anyone else's like this? I'm going to take it to the range today to see if it is still zeroed after taking it off. Hopefully it is... |
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i was kinda thinking that too, or it could even be my buis thats throwing me off. it's the surefire m81 rail. I had to change the hanguard cap to a round one since i had the triangle one. I installed it last night so late that i didn't even post pics!!! LOL! the fact that i was tired could be it too. i've been at work all day, and can't wait to go home to inspect further... |
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It is probably appears to be off due to tolerance stacking. The real test is when you zero your sights. I have a Bushy M4 upper that when you look down along the carry handle/rail, over the handgards and at the front sight base everything looks out of wack, but it zeroed with five clicks right windage. BBossman |
Index pin? Are you talk about if i removed the barrel? If so, I didn't, i just took the flash hider off and the FSB, to take that triangle hanguard cap off and put a round one on. |
In that case it will depend how close you got the FSB back to it's original position. Pretty tough to do. But as long as it zeros again, no worries. |
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Is this the AK board? JK I have an older Bushmaster A2 that has a very slightly canted FSB. I never noticed it until I put a carry handle ARMS mount on it. Now, when looking through the sighting channel, I can see it looks very slightly off. Since it zeros fine, I try to ignore it. But I know that can be difficult when you want everything perfect (like all of us do). |
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Well, I just got through shooting it. i must have done something wrong, cause point of impact proves it has indeed canted towards the right. maybe i'll take it apart and put the pins in backwards. (maybe thats what i did in the first place. It's a RRA upper, and the pins seem to be the same on both sides. Anyone know what I did wrong? could it be the barrel shifted or something? hmmmm... |
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How did you hold the upper steady when you took the FH off? The indexing pin in the barrel matches a notch in the upper and alligns it. IF it was good before you did the work then the FSB is probably square to the indexing pin. I think youd have to seriously do some damage for the FSB not to relocate within a degree or so from its original position after you reinstall it. |
I took the flashhider off by holding the barrel with my hand actually. I was trying to figure out how tight it was to see if i really needed to but those barrel vice jaw thingies. it came off really easy which supprised me. I wasn't expecting it to budge. I'm sure thats not why it moved. it has to be something with the FSB itself... I'll try fixing it today after work... hopefully i don't do any more damage...
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Dont think so. The FSB is located by straight pins on a RRA.... there is hardly any possibility of reinstalling the same FSB on the same barrel... and not get it almost exactly where is was.... Since there is no room for adjustment, the pins locate it in the same place every time. Did you change the rear sight at the same time? You say it used to zero with the windage set to machnical zero? If you did not change the rear sight, and only removed the FSB then reinstalled it.... it should zero in exactly the same place. If it does not, then I would guess you rotated the barrel in the upper receiver, due to a slightly loose barrel nut, because there is some play between the indexing pin and upper receiver slot. Just how far off are we talking about? Are you having to move your rear sight all the way to the right to get it to zero... or just several clicks? |
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Well, don't know if this was the problem, but i took it off again. The front pin was broke in 2 pieces. Don't know how it happened, but it did. I just took one from my other RRA upper that is not in use right now. I'm thinking you are right on the rear sight. I did take it off, and i think the fact that it's canted towards the left is playing an eye trick with the front sight. After taking the handguards off both my RRA uppers, they look like they are positioned in the exact same place. I hate it when i THINK something is wrong. The only thing wrong is right now so I'm happy. Thanks for all your posts. At least you tried to help the helpless...
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