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Posted: 10/4/2009 5:55:07 PM EDT
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I finally decided on the YHM front and rear push button flip up iron sights for my new Aramlite M15. What a disappointment. I have gunned, mostly hunting, for over 30 years and never had this problem. I expected to be on the paper at 50 yards after a few rounds but that didn't happen. Moved up to 25 yards and my group is at the top of the top target (put 2 targets on a 2 1/2 foot high backer board, 1 on top, 1 on bottom). Got on the paper but only did this by aiming at the bottom of the backer board, nearly 2 feet below the center of the top target. Shot 70 rounds and called it quits with no improvement.
The front sight is a globe style, the rear has both large and small peep sights, The front in mounted on the gas block ahead of the forearm and the rear is set on the back of the picatinney rail. It just doesn't seem right to have to aim so low to get on target. Do I not have the sights set up correctly? Do I have the wrong sights? Am I doing something wrong? Appreciate the help! Bill |
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If these are your sights the front is designed to be mounted on the same plane as the rear sight, ie. not on the gas block.
bigger pic 
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YHM makes two different front sight heights. One is designed to be mounted on the gas block, and the other is designed to be mounted on a free float rail system. The height is different because of this. Take a look here...
This one is designed for mounting on gas blocks: 
And this one is designed to be mounted on a free float rail: 
- Now, you're saying that your front sight is mounted on the gas block, right? And your shots are hitting way high when you're aiming at the bottom of the target? That would tell me that you might have the wrong sight base for your application. If you're using the shorter of the two bases shown above on the gas block, that would account for your shots going WAY high like you're describing. Take a look at your front sight and see if that's what it is. If that's the problem, just send it back and get the correct one. |
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http://img101.imageshack.us/content.php?page=done&l=img101/6807/img0136j.jpg&via=mupload
Not sure if I got the picture loaded but here goes. I was told by the supplier that these sghts would work with the Armalite M15. They are the exactly the ones shown by tumble weed above. The front sight is mounted on what I think is referred to as the gas block. It has a picatinny type top and the sling attaches at the bottom of it. If the picture came through you can see the front and rear sights are on the same plane. tell me if you think it is the wrong sight. http://img101.imageshack.us/img101/6807/img0136j.jpg |
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The only way to be sure is to measure the height of the front sight post above the bore, and measure the height of the rear aperture above the center of the bolt carrier. These measurements should be very close to each other.
It also looks like your rear sight is mounted forward a bit, reducing your sight radius. This wouldn't cause the problem you're describing though. |
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Ok, I will do that. I received a reply from the supplier (Valhalla) and he is willing to work with me. I have a question that may seem a little dumb.
Somewhat rusty with geometry but considering I am hitting high when aiming on the target center, I assume a lower front sight would bring the sight plane down getting closer to the center aimed at? Thanks. |
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Quoted:
Ok, I will do that. I received a reply from the supplier (Valhalla) and he is willing to work with me. I have a question that may seem a little dumb. Somewhat rusty with geometry but considering I am hitting high when aiming on the target center, I assume a lower front sight would bring the sight plane down getting closer to the center aimed at? Thanks. If your front sight is too low your shots will hit high. Raising the front sight in relation to the rear sight will make your shots hit lower on the target. Your front sight appears (to me anyway) to be lower than the rear one. I'm gonna guess the supplier accidentally gave you a front sight designed to be mounted on a free float hand guard rail instead of the one made for use with the gas block rail. If they'll allow you to trade your front sight for the correct one, I'll bet your problems will be solved. |
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YHM makes a gas block riser to install on the railed gas block so that the QDS same plane front sight will work properly.Go to the YHM web site and look under mounts.
Otherwise the QDS sights are as mentioned intended to run on the same plane...that is the gas block would have to be the same height as the top of the receiver rail. HTH ETA link http://yankeehillmachine.com/store/product491.html |
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