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Muzzle brake causes MULTIPLE FEET off POI shift on sub moa rifle.

Discussion in 'Rifle Discussion' started by Eludnu, Jun 28, 2015.

  1. Eludnu

    Eludnu Oregon Member

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    The details. High end AR-47, Warne single mount base mounting Vortex VHS 4307. Sub MOA at 100 yards. (At the end of the story) First shot at 50 yards, next county over. Dial in way right, way up. shoot. Not on paper. Multiple rounds later, scope was at max right, max up, and shooting over 1 foot low and at least 2 feet left. :eek:

    The spotter in the group suggested the only possibility was the full forward venting muzzle brake. Removed, and reset scope to zero. 5 shots later, 3 rounds, one jagged hole at 100 yards.

    I am still flabbergasted. Had a can been on the end, it could not have resulted in anything less than multiple baffle strikes and a side exit. How in the world can a muzzle brake be THAT BAD on POI?
    Needless to say, now looking for a new muzzle brake.
     
    Last edited: Jun 28, 2015
  2. Riot

    Riot Benton County, Washington Well-Known Member

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    Might not even by the muzzle break, itself...the threads might not have been cut straight. If the new muzzle break is still causing issues, leave it off...accessories (hand guards, bayonets, etc.) touching the barrel do funky things to bullets sometimes.
     
  3. Mark W.

    Mark W. Silverton, OR Bronze Supporter Bronze Supporter

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    It can also be the same effect real hot loads have on a revolver with a very short barrel. If the powder is still burning as the bullet leaves the muzzle it is possible for the unrestrained pressure to "tip" the bullet a tiny bit as you can imagine this screws accuracy.

    Your forward blasting break maybe doing something similar. Also check to see if there are any wear marks around the bore of the break. It may not even have to touch just allow an uneven pressure to escape causing the bullet to be "tipped"
     
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  4. mjbskwim

    mjbskwim Salmon,Idaho Well-Known Member

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    man that far off it seems it would be striking the brake.
    When you did hit paper with the brake on,what did the holes look like?
     
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  5. Velzey

    Velzey Estacada, Oregon Gunsmith Gunsmith Bronze Vendor Bronze Supporter

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    Boy that's an odd one! I to think the threads may not be square to the bore. What's the inside diameter of the break? It sounds like you may have contact!
     
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  6. Riot

    Riot Benton County, Washington Well-Known Member

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    Contact with the muzzle break would be very apparent and I've only ever heard of a threading being cut wrong on custom cut jobs...I'm thinking, though, that for the bullet to be thrown off in a specific direction that either the threading isn't square, the break ports are just not evenly cut or the muzzle break is just lopsided.

    Obviously the smartest way to go about this is to simply replace the break and to see if it still is throwing the bullets off...

    However, you can also bring the target in a little closer than 100 yards and mess with the current break.

    Unthread the muzzle break just a little bit (maybe like a quarter turn) then shoot at your target...repeat a few times (turning it a 1/4 turn each time)...if it throws the round off in a different direction, it's your muzzle break...if it holds- it's your thread.

    *Caveat*

    If for any reason you think that the bullets have -or will- make contact with the break, don't do the above...
     
    Last edited: Jun 28, 2015
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  7. jbett98

    jbett98 NW Oregon Bronze Supporter Bronze Supporter

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    You could leave the brake on and rotate the firearm 45* to see what happens.
     
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  8. Velzey

    Velzey Estacada, Oregon Gunsmith Gunsmith Bronze Vendor Bronze Supporter

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    I've seen misalignment on several factory barrels...Savage, Smith and Wesson, and a Remington. So it happens. It could be the smallest little nick.. Rotate is a good idea! Have you talked to RRA about it?
     
  9. solv3nt

    solv3nt Portland Well-Known Member

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    Gangster style is 90 degrees.
     
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  10. ogre

    ogre Vancouver, WA Well-Known Member

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    I suggest that you start by closely looking at your brake. If the bullets are striking it I believe that you should see gilding metal contact on some part of the brake.
     
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  11. Eludnu

    Eludnu Oregon Member

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    Nice and round.
    The spotter, took the brake home so I too am curious to take a closer look at it's exit.
     
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  12. Eludnu

    Eludnu Oregon Member

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    My buddy took the brake home as it was one his co-worker was interested in trading. (A fair trade might include a toothbrush with no bristles, or a wheelbarrow with one handle.)

    I will get it back and run a very close inspection, including mic
     
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  13. DizzyJ

    DizzyJ Lost Member

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    I too am curious as to whether or not it (the bullet) was hitting the brake.
     
  14. mjbskwim

    mjbskwim Salmon,Idaho Well-Known Member

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    I'm guessing here,but if the hole in the target was perfect,then it is the way the ports are cut.
    If it's hitting the brake,then that little 55gr pill would tumble
    I guess we will find out soon
     
  15. Eludnu

    Eludnu Oregon Member

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    Correction to my previous comment. After two shots of not hitting paper with significant adjustment to the scope, I moved to dirt so we could witness impact more accurately. So, I have no idea if the holes on paper would have been clean, as I never hit paper with the brake on. Once we realized the scope was at max elevation and windage, we pulled the brake. A quick look did not show obvious strikes.

    The clean holes thorough the paper where with the brake off. Sorry for the mistaken info.
     
    Last edited: Jun 28, 2015
  16. v0lcom13sn0w

    v0lcom13sn0w Keizer, or Well-Known Member

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    try a different brake? i use the surefire procomp with EXCELLENT results.
     
  17. mjbskwim

    mjbskwim Salmon,Idaho Well-Known Member

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    :rolleyes:I just don't see how you expect us to help with government type info.:s0123:
    Oye vey
    Yeah I would believe the FH would definitely show a hit or not
    Never heard of the gas flow changing the POI like that though.
    Is this a new product for the manufacturer? I'm sure they would like to know your results,too
     
  18. Eludnu

    Eludnu Oregon Member

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    "Government type info" LOL. At least I offered an apology.
    Some people. Shoot them with a new bullet, and they still complain. :D

    I do not know yet what exactly caused the POI shift. Many of you have offered sound input into what the culprit could be, that I had not considered prior. Until I can narrow it down a bit more, I want to be careful about throwing the bus into reverse and driving over the brake manufacturer. No matter the outcome, it was one of those moments where all who witnessed it where set back a bit.
     
  19. 308

    308 ΜOΛΩΝ ΛΑΒΕ ΜOΛΩΝ ΛΑΒΕ Platinum Supporter Silver Supporter

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    The muzzle brake is not causing the POI shift. The fact that the projectile is striking the muzzle brake prior to leaving the rifle is. I've been down this road a few times especially when a crush washer is used.
     
  20. 308

    308 ΜOΛΩΝ ΛΑΒΕ ΜOΛΩΝ ΛΑΒΕ Platinum Supporter Silver Supporter

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    ....and while I'm at it :) Once the bbl heats up you will be chasing your POI all over the target.