New build shooting way right

Discussion in 'AR-15 Discussion' started by KHickam, Jul 7, 2015.

  1. KHickam

    KHickam Member

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    Howdy

    Last night after receiving a new premium mid length upper from PSA - I put it together on the lower I had built and put on the BUIS UTG sight I had bought for my lady

    Any way - taking it out to zero using a good quality ammunition AE 223 55 gr - gun is 1/7 in a 16" barrel.

    We fired it off bags while prone - way we zeroed our rifles in the military and even after moving the rear sight almost all the way left it still shoots a bit right

    figured it was Denise's trigger control but it shoots right for me too even though it was grouping pretty well - 1/2 to 3/4 inch with a three shot group (also taught in the military)

    Wondering if it could be the sight - because my MBUIS sights on basically the same gun shoot center without much adjustment

    Suggestions?
     
  2. MisterMcCool

    MisterMcCool Well-Known Member Supporter

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    I have heard of loose gas blocks causing inaccuracies like this.
     

  3. Triumphman

    Triumphman Active Member

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    I've heard of this, but on other assemblies.

    You first need to find if there's any abnormalities of straightness between the receiver and barrel.

    Run a straight-edge along the centerline of receiver and along the barrel's centerline all way to front sight to help determine any cants off to the right.

    Now, knowing if barrel/receiver are straight, you need to determine if front sight is canted off.

    Put assembly in vise to hold in a vertical 90* and put a straight-edge along each side of the front sight to see if it's mounting is vertical also. If not you found the problem. Sometimes you can see a sight's cant by visual.

    Another source of shooting either right or left, is remove the handguard and check tightness of barrel nut and that it conforms to proper torque. I've heard of looseness in this area before from PSA.

    If all straightness checks and barrel nut check are good, then I would say your UTG sight is bad. It's possible it's an airsoft sight and not a good AR sight. If you want a good sight for not much money, I use Pro Mag on my ARs.
     
  4. Sniper03

    Sniper03 Supporting Member Supporter

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    Hickam,

    Lets see some pictures of the rifle.
    Are we speaking of a standard front sight housing (A-Post)?
    If so it could be very possible PSA has the Index Pin on the Barrel Extension and the Front Sight Housing completely out of alignment. Usually caused by misdrilling when installing the Front Sight Housing (A-Post). I am saying this because you said you had the BUIS Rear Sight on another rifle and it was OK. So pictures might help. If it is out of alignment being a new barrel they would get it back. When this happens with standard sights usually the Rear Sight Aperture is adjusted clear over against the side of the Rear Sight Aperture Housing and you still do not have enough adjustment to correct the windage for a center target hit.
    So give us some pictures on the front and rear sight in relationship with the barrel.

    03
     
    Last edited: Jul 7, 2015
  5. KHickam

    KHickam Member

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    Okay we are trying - I meant I have cranked the apeture all the way over practically - and hits are still about 1/2 inch right. There is not much if any adjustment left for the apeture
     
  6. mopowerbmx

    mopowerbmx New Member

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    Try a different buis. Without pictures it is hard to say. I made the mistake of buying a cheap buis and it was way off as well. I went with a magpul and it was spot on after I installed it.
     
  7. skibbyshot

    skibbyshot New Member

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    A couple of thoughts - What distance are you shooting? Have you tried different ammo?
     
  8. KHickam

    KHickam Member

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    We put a Magpul BUIS on it and we did have to crank it left but not nearly as far as the UTG sight - we were shooting 62 gr M855 the second time we were zeroing it from 50 yds
     
  9. Triumphman

    Triumphman Active Member

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    That does sound like the front sight/barrel slipped in the holding fixture when they drilled for the sight/gas holding pins.

    Shoot some weak Wolf and Tula ammo to see if it still ejects correctly without short stroking. If it does, call PSA to start a return for warranty as the gas block isn't aligned correctly with gas hole.
     
  10. Alpha1Victor

    Alpha1Victor New Member

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    You check the crown?
     
  11. JonM

    JonM Moderator

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    pics would help a lot
     
  12. fsted2a

    fsted2a Active Member

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    Here is a possibility, although being PSA it is less likely: there is a tiny amount of wiggle room between the detente/pin on the barrel, and the slot it goes into on the upper receiver. If you don't center the barrel perfectly and have something to hold it there while tightening the barrel nut, the torque will cause the detente to move left (from the shooters perspective), causing your aim to go right. The tier 1 manufacturers have tools to keep it centered while tightening, which is why they are so close to being zeroed leaving the factory. I personally use a couple of toothpick tips, one on each side, to keep the detente centered on my builds. OP, I don't know if this helps any, but I thought having my perspective might help your understanding.