Flip up sight problems
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Old 07-03-2012, 11:44 AM   #1
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Default Flip up sight problems

I've been having problems sighting in my AR. The first set of flip up sights I had on it were pro mags and they were shooting way high even with the front post all the way up. So I purchased magpul sights. Those shot way low. I checked to make sure the gun was level and it was. Anyone have problems with this before? I have a bushmaster xm15-E2S.
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Old 07-03-2012, 12:41 PM   #2
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Quote:
Originally Posted by FearTheFree7 View Post
I've been having problems sighting in my AR. The first set of flip up sights I had on it were pro mags and they were shooting way high even with the front post all the way up. So I purchased magpul sights. Those shot way low. I checked to make sure the gun was level and it was. Anyone have problems with this before? I have a bushmaster xm15-E2S.
Post a pic so we can have a look but my first thought is that you have "same plane" sights mounted on a gas block. Is the front sight on a gas block or on the hand guard rail? If on a gas block, is it taller than the rear sight?
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Old 07-03-2012, 01:43 PM   #3
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In addition to what Jpyle said, BUshmaster uses commercial height sights, not milspec. If you're mixing a BM front with a milspec height rear you have to unscrew the front post so much it flops around. BM does sell a $6-7 tall front sight post to fix this. Can't remember what they call it but Colt was in the name. I had to put one in my ArmaLite to get it to zero with a milspec rear.
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Old 07-03-2012, 01:43 PM   #4
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I put a full rail hand guard on mine as I originally had the FSB on it and my sight was way off after putting the troy handguard on ,my magpuls were shooting way way high and I literally have it unscrewed most of the way out but finally got it ,my rear sight is all but 1/8" from the right . Im not going to try to move the rail around to adjust its lined up perfect with the receiver . its set and Im leaving it there . not all brands are the same height and hopefully the magpuls will work for you .
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Old 07-03-2012, 09:42 PM   #5
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Quote:
Originally Posted by Jpyle

Post a pic so we can have a look but my first thought is that you have "same plane" sights mounted on a gas block. Is the front sight on a gas block or on the hand guard rail? If on a gas block, is it taller than the rear sight?
They front sight is on the gas block and they look to be on the same plane.
image-4285508320.jpg   image-4132563950.jpg  
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Old 07-03-2012, 10:04 PM   #6
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Anyone have AutoCAD or software that can draw a couple of linear lines on that picture to compare the sights in relation to the bore axis?

It appears, and I took a copy and was just playing with it on the laptop here with a cut and crop program, that your sights are not in line with the bore axis and I think that might be contributing to your problem.

Do you have a micrometer by any chance? Where you can get the measurements of the two different front sights and see what the difference is in post height?
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Old 07-03-2012, 10:08 PM   #7
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Not anymore. I'm done with auto-cad sorry. You may be able to use a carpenter square to get a pretty good idea.
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Old 07-03-2012, 10:13 PM   #8
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You won't want to run that front sight on your gas block. MagPul advises thatthese were made to be run on handguards. Gas blocks can get hot enough to melt the sight.
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Old 07-03-2012, 10:15 PM   #9
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Quote:
Originally Posted by SSGN_Doc
You won't want to run that front sight on your gas block. MagPul advises thatthese were made to be run on handguards. Gas blocks can get hot enough to melt the sight.
Did not know that. Good to know. Ty
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Old 07-03-2012, 10:22 PM   #10
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Originally Posted by mountainman13 View Post
Not anymore. I'm done with auto-cad sorry. You may be able to use a carpenter square to get a pretty good idea.
Yeah, I haven't had a license for it in years. Just messing around it appears the front sight is high in relation to the rear sight and where I assume the dead center of the barrel should be, forcing the front of the barrel down.

I think you might just not have the correct sights for your application. Quentin mentioned BM doesn't use mil spec above. Are the Magpul sights mil spec?

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