GUN question about accuracy v.barrel profile

Discussion in 'On Topic' started by Paul Revere, Jun 11, 2009.

  1. Paul Revere

    Paul Revere OT Supporter

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    I made this thread on M4 Carbine last night but only got 1 reply.

    I ordered two Surefire FH556-212A flash hiders in the group buy, and have a question about rifle accuracy after re-profiling a barrel and attaching a new flash hider.

    I currently have a CMMG M4 SOCOM profile 14.5" upper; if I sent it in to have the Phantom cut off, Surefire permanently attached, and the barrel tuned down to a regular M4 (or even lightweight) profile, would that affect the accuracy of the rifle?

    I am quite pleased with the way this rifle preforms (for those of you familiar with Zombie Targets I put 10 rounds in one of the corner silhouettes @ 100yds my first time shooting that distance) and if there would be a significant change in its shooting I might reconsider the process.

    I would assume that the accuracy would not be affected granted I got the work done by a reputable smith, but I would like some more input.

    No thread is complete without pictures:

    Rifle in question:

    [​IMG]

    Surefire FH:

    [​IMG]

    Thanks guys! :wavey:
     
  2. PanzerAce

    PanzerAce Active Member

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    Ask Dennis :mamoru:
     
  3. Paul Revere

    Paul Revere OT Supporter

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    Too bad he doesn't post on here.
     
  4. Paul Revere

    Paul Revere OT Supporter

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    Just emailed him :o
     
  5. Razardica

    Razardica Active Member

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    I don't think the barrel profile will affect raw accuracy but I do think there will be more variance in your shots.
     
  6. Paul Revere

    Paul Revere OT Supporter

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    I guess the bottom line is if I don't want the accuracy affected, don't change anything :hs:
     
  7. phrozenlikwid

    phrozenlikwid New Member

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    In high accuracy pursuits, you would likely find people who would shy away from this. The theory being, turning down the barrel after the stress relief methods of the maker can introduce new stress points in the steel, thereby doing strange things to barrel harmonics (and in the worst case, causing bore diameter inconsistencies). In short, bad accuracy juju. It goes a lot deeper than that, for a plethora of different reasons, but search around and you will find some bleeding heart flamewars about the topic.

    I personally think most of that is bullshit outside of perhaps the BR realm, and even then likely still so. Button-Rifled barrels (which yours is) usually undergo the stress relief process BEFORE (generally speaking) being profiled to begin with, which is something that most dissuaders seem to forget, or don't have an answer for.

    When put into context, think about it this way: You are shooting a carbine with a (in comparison to high end cut-rifled stainless tubes used on something like a BR gun) mediocre quality barrel (with a arguably VERY inconsistent bore if CL'd), cut with a generous chamber specs, shooting ammo that is likely low quality surplus (again, in comparison), using low powered optics, generally in positions least conducive to pure accuracy pursuits, at close ranges (what's the furtheset you shoot, 200 yds?). Do you really care in the event that some minutia of bad juju is introduced that causes you to see a 1/72MOA shift at longer ranges than you generally shoot? Could you honestly even drive that rifle well enough to notice a 1/2MOA difference under typical carbine conditions? I couldn't, and I doubt many could.

    In short, cut that bitch up. Light is right.
     
  8. +1 To all of this. Saved me a lot of typing.
     
  9. Paul Revere

    Paul Revere OT Supporter

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    :coold: THIS is the type of response i've been looking for.

    :h5: thanks bro.
     
  10. Paul Revere

    Paul Revere OT Supporter

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    any one have recommendations for a good AR15 smith? i was looking at kurt wala before be passed away :sad2:
     
  11. SnakeEater

    SnakeEater OT Supporter

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  12. Paul Revere

    Paul Revere OT Supporter

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    $95 for contouring the entire barrel (includes parking)

    not bad


    $100 for pinning a Surefire to the barrel :ugh2:

    and according to their site:

    :wtf: any proof of this?
     
  13. phrozenlikwid

    phrozenlikwid New Member

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    What you are wanting done should be able to be done by any halfway-competent 'smith/machinest. I wouldn't necessarily limit my selection to only "AR" 'smiths.
     
  14. kds000

    kds000 New Member

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    check if tornado technologies does contouring..they do good work and pinned my blackout for $30 compared to adco's $100.
     
  15. Keesh

    Keesh New Member

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    Tornado tech kicks ass, Mike does awesome work.
     
  16. Fire Sauce

    Fire Sauce New Member

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    :love: my 16" pencil barrel. It does everything I ask it to.
     
  17. Paul Revere

    Paul Revere OT Supporter

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    so i was able to verify that SF voids the warranty on any mount that is "modified" - and drilling into it/welding it is DEFINITELY modification :rofl:

    i think what i'll do is leave my CMMG alone and put one of the FHs on my 16" BCM, and the 2nd on my 18" SPR (once its built).
     
  18. Razardica

    Razardica Active Member

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    You know those are called K-can mounts for a reason?

    lol lol
     
  19. Sardaukar

    Sardaukar Active Member

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  20. SnakeEater

    SnakeEater OT Supporter

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    is that the same guy who fucked a bunch of people over?
     
  21. phrozenlikwid

    phrozenlikwid New Member

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    Yeah, I was under this impression as well. Randall, I believe his name was/is.
     
  22. Sardaukar

    Sardaukar Active Member

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    His name is Randall. Lives in CA and is recommended by many members on calguns.net. What's the story you're referring to? You've peaked my interest.
     
  23. Sardaukar

    Sardaukar Active Member

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    Looks like I don't visit CGN enough. Now I really want to know what happened.
     
  24. phrozenlikwid

    phrozenlikwid New Member

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    Dunno if it was a CGN thing (I don't frequent there). Wanting to say it was more of a ARFCOM/everywhere else thing a year or few ago. I think it was pretty much the usual, guy starts doing good work cheap, guy gets overwhelmed, things fall apart, guy tries to dissapear with peoples guns/money sitting around.

    First hit from Google I could find:

    http://www.m4carbine.net/showthread.php?p=349610

    I know there are a lot more, I just haven't really looked.
     
  25. phrozenlikwid

    phrozenlikwid New Member

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