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12/8/2011 2:36:07 PM EDT
So I took out my bushmaster today, which I have for about a year but never get to shoot. Its shooting about 4 in to the left and 7 in down. We tried two different shooters, two different scopes, a bore guided laser, and a shooting mount. None of those things made a difference. The rifle has about 500 rounds through it. Does anyone have any ideas whats causing this, and how to fix it?
12/8/2011 3:15:46 PM EDT
[#1]
if its grouping at the same spot then the sights/scope just need adjusted.
Whats distance are you talking about?
A bore sighter just gets you close, gotta zero from there
12/8/2011 3:43:54 PM EDT
[#2]
That's exactly what we did saddlerocker. We started at 100 yds, and weren't even touching the paper. So we moved it in to 50. I maxed out the up adjustment on my acog, and was still low. We did the same thing with my friend's scope.
12/8/2011 3:48:33 PM EDT
[#3]
well as long as its grouping, the rifle should be fine.
Is it shooting decent groups, albeit way off center?

Unless maybe the rail that your mounting all the optics and back up sights on is way out of spec.
Or maybe the barrel is somehow not centered

You sure the optics were mounted correctly?
Did you try iron sights? (flip or whatever back ups)
Edit: I see you said a Bushmaster
12/8/2011 3:50:32 PM EDT
[#4]
just wondering due you have a flat top upper, or one with a carry handle?
12/8/2011 4:09:18 PM EDT
[#5]
The whole upper is bushmaster factory components. I've installed an Adams arm piston, a new flash hider, and that's it.
I'm pretty sure it's not the optics, because the flip up sights are way off too.
The groups were prob .75 in. Just way off center.

Yes it is a flat top.
12/8/2011 4:20:50 PM EDT
[#6]
Did it shoot okay prior to the new parts?  Did you remove the barrel at any point?
12/8/2011 4:36:22 PM EDT
[#7]
Could be the face of the upper isn't square with the bore. They sell a tool to lap it square, or return it.
12/8/2011 4:37:44 PM EDT
[#8]
It's always had this problem. I was told that it was a breaking in issue by my old boss, manager of a gun range, so I just took his word on it.
12/8/2011 5:15:06 PM EDT
[#9]
unfortunately Bushmaster probably wont touch it now with the piston kit installed.(I would still contact them and try)
Should have been sent back.
I cant imagine spending the money on a piston kit for a rifle that cant zero

I would send it to ADCO or someone who has tons of AR experience and hope they can fix it.
Or you can buy tools and try diagnose the issue yourself.
12/8/2011 7:47:21 PM EDT
[#10]
Your old boss didn't know much about firearms, that's for sure.  Take it to a competent gunsmith and have the upper receiver trued or replaced (it's only a $75 part).



Also, if you have the barrel removed have it checked for straightness.

12/8/2011 9:02:37 PM EDT
[#11]
Im thinking about sending it to Rainiers arms ( I have done alot of business with them and have no compliants). I dont have any experience with adco.  I'm just a little upset that I spent alot of money on a rifle that can't even be zero'd.
12/9/2011 11:17:37 AM EDT
[#12]
Have you tried without flash hider/comp?  Or sighted though the barrel while upper propped in a bag rest?  At 50yds, you should be able to get the group pretty darn close to POA by sighting through the barrel.  Adjust sights a couple inches low to where you spot through the barrel and the sights adjust opposite when you are trying to bring POA to the spot you see through the barrel...
12/9/2011 12:02:22 PM EDT
[#13]
I normally use a laser bullet bore to check the sight and before I install the comp... Now if I notice I can't get it on target Ill try shooting it without the Comp to make sure the bullets are not hitting and tumbling or just getting kicked to one side... unless you shot it before and didn't have that problem then I would say its in the build and start by taking it apart to the receiver and checking from there forward... I have to had to lap the receiver to get them square, Easy to do just expensive tool to buy.....
12/11/2011 10:09:08 PM EDT
[#14]
So I took the rifle back to the range Saturday. I tired different ammo, we placed the rifle in a shooting rest, and shot it without the flash hider. I got the same results. I guess I'll have to send it off now.
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