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Thread: compensator opened groups

  1. #1
    Boolit Buddy
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    compensator opened groups

    I added compensators to my ar15's and the grouping went out window . I know the harmonics have changed but from 1" to 8" at 40 yds is radical.

    16' bbl. 1:7 twist

    62 grn. powder coated gas checked cast coww

    21 grn. IMR 4895

    Any input would be appreciated, should I go up in the charge or just do a new ladder test ? I cant hit the broad side of a barn from the inside.

    CC

  2. #2
    Boolit Grand Master


    Larry Gibson's Avatar
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    Doubt the compensator has anything to do with it. To high velocity, to high RPM.

    Take the comp off and recheck accuracy w/o.

    Larry Gibson

  3. #3
    Boolit Buddy
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    Thanks Larry but it shot great with the flash suppressor. I'll probably switch it back so I can use up lots of ammo I've loaded for this ar.

    CC

  4. #4
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    I would check the comps for bullet skimming the bore. Some comps (and a lot of cheaper barrels) are not threaded concentric to bore
    The longer the comp the more chance of impact
    [SIZE=4][B]Selling Hi Quality Powdercoating Powder

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  5. #5
    Boolit Buddy
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    Looks like there is some lead and Carolina blue on the 1st port on the right hand side.

    CC

  6. #6
    Boolit Master
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    Comps need to be symmetric!
    Thrust will scew the barrel in odd ways if not.

  7. #7
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    Well there is the problem
    now you need to find out if the comp or the barrel is threaded wrong
    You could always bore the comp center hole larger but it will reduce some effectiveness of the cono
    [SIZE=4][B]Selling Hi Quality Powdercoating Powder

    I carry a Nuke50 because cleaning up the mess is Silly !!

    http://www.bing.com/search?q=nuke50&...7ADE&FORM=QBLH

    I am not crazy my mom had me tested

    Theres a fine line between genius and crazy .. I'm that line
    and depending on the day I might just step over that line !!!

  8. #8
    Boolit Buddy
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    I'll bore it out it's just for Cali laws, flash suppressor is too scary in this state.

    CC
    Last edited by clearcut; 07-09-2017 at 07:18 PM.

  9. #9
    Boolit Buddy
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    So close all the doors and windows, don't give up before the miracle happens !

  10. #10
    Boolit Master
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    You can always take it off and screw a thread protector on in its place.
    jim

  11. #11
    Boolit Bub
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    I had a muzzle brake that leaded up considerably but shot jacketed bullets just fine. Clean it and try some FMJ and see what happens.

  12. #12
    Boolit Master
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    Sounds like your rounds are striking the comp as they exit. As the others have said something is not concentric at the muzzle.

  13. #13
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    Texas by God's Avatar
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    Quote Originally Posted by koehn,jim View Post
    You can always take it off and screw a thread protector on in its place.
    Ditto

    Sent from my SAMSUNG-SM-G930A using Tapatalk

  14. #14
    Boolit Master
    high standard 40's Avatar
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    Bullets don't have to strike the compensator to have a negative effect on accuracy. The expanding powder gases are still pushing that bullet for a short distance after it exits the barrel. Just like a bad crown can disrupt accuracy, a non concentric attachment to the barrel can disrupt accuracy. Been there, done that. My brother had a bad threading job on a 223 barrel and the mounted brake destroyed accuracy. We took the brake off and it shot great again. Bullets were not touching that brake but it was threaded loose so it was not concentric with the bore.

  15. #15
    Boolit Master


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    Are we tailing a suppresser/silencer it as it is California? No idea myself.

    Recoil, flash or sound please which. There are many answers to a correct question.

  16. #16
    Boolit Master Moleman-'s Avatar
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    Some of the muzzle attachments are threaded with a tap when they really should be single point threaded on a lathe which is much more accurate. I ran into one comp for a mini14 that acted like that. After a few rounds it was clear something was happening and there was copper on the inside bore of the exit of the comp. Do you have a range rod or something close to bore dia to check alignment?

  17. #17
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    Quote Originally Posted by high standard 40 View Post
    Bullets don't have to strike the compensator to have a negative effect on accuracy. The expanding powder gases are still pushing that bullet for a short distance after it exits the barrel. Just like a bad crown can disrupt accuracy, a non concentric attachment to the barrel can disrupt accuracy. Been there, done that. My brother had a bad threading job on a 223 barrel and the mounted brake destroyed accuracy. We took the brake off and it shot great again. Bullets were not touching that brake but it was threaded loose so it was not concentric with the bore.
    high standard 40 got it right. On may types of muzzle attachment the gas does do funny things to the bullet. One of the reason I build my AR's with target crowns. I don't want any muzzle attachment on them.

    For sure there many of these things that aren't threaded straight.

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BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
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LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check