so um.. is it supposed to do this? (AR15)

K

Kaylee

New member
AR-15, Bushmaster, A2 sights. The rear sight block seems to have some kinda spring pressure torquing it off center. It's angled about 5-10 degrees counterclockwise off the bore axis.

Hrmm.. I THOUGHT something was wierd when it needed 8 clicks left to sight in.

So um... what's going on, and how do I fix it?

Thanks!

-K
 
I wouldnt worry about that too much. I did at first when I first got my Bushmaster Shorty AK. The I took it to the range and sighted it in. There werent any problems at all. The M-16's I use in the Air force are just like that too. Ive asked around and noone cane really give me an explanation why the rear sight cants to one side like that. Also I wouldnt worry too much about having adjust 8 clicks like you did. I once was issued an M16 that I had to crank over 27 clicks to the right. The rear sight looks weird as hell but the gun shoots pretty damn good.
 
Kaylee,

Not a problem.... normal condition for A2 rear sight.

If you have to crank over "too far" one way or the other, the front sight base is probably slightly off kilter.... again, nothing to worry about unlees something is either loose or non-functional.

If you plan to shoot "X course", out to 600 in Service Rifle competition, you will need to have it checked out by a smith who knows AR's. At 600 in wind, you just might need the entire windage range. If your sights are "off center", you could run out of clicks if the wind is strong enough from the wrong direction.

my .02,
Swampy
 
Swampy's correct

Funny how BM's are smitten with the sight alignment problem. I assembled my AR, boresighting to eliminate this problem. I wonder why Bushmaster hasn't tried this?

Their method of whacking the FSB with a mallet is iffy at best. I would recommend a reassembly of the barrel with the upper, paying careful attention to the index pin and its corresponding slot, shimming if necessary.

On reassembly, lube the barrel nut and extension with dry moly. Hold the upper in PRA blocks, do not clamp the barrel into a vise! Boresight to make sure windage is on. This requires lots of trial and error but if you do it, it will be correct. Mine is 2 clicks from absolute center.

FYI, I think BM is getting cheap. First, no feed lips on the barrel extension. Then FSB problems.
 
Kaylee, the twist in the rear sight is normal, but should not require your zero to change very much at all as the post is directly under the sight and twists on the axis.

HOWEVER: It your front sight on straight? Many stock ARs come from the factory with a front sight on over or under timed.
 
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