Accurizing tricks and tips?

Discussion in 'Technical Discussions & Troubleshooting' started by desertdweller, Mar 24, 2017.

  1. desertdweller

    desertdweller New Member

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    What's in your bag of tricks to squeeze the most potential from your 556?
    Each rifle system I have owned seem to have idiosyncrasies that when tuned properly had the possibility to dramatically increase the accuracy of the overall group size.
    Are there similar tricks that can affect the accuracy of the 556?

    I was considering tightening the gas tube to remove any movement and play, shimming the upper and lower receiver to tighten the fit and possibly switching the folding stock/brace mechanism out for a fixed assembly.
    Any other thoughts?
     
  2. CPTKILLER

    CPTKILLER Active Member

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    1. Find which ammo your specific rifle is most accurate and reliable with.
    2. Practice.
    3. Sights or red dot or scope.
    4. Trigger job.
     
  3. Iamscotticus2

    Iamscotticus2 New Member

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    This rifle had better barrels earlier in production, but after that, it is what it is.
    Some have reported wandering POI with heat. Not that unusual with piston gas block rifles, but more common with this pencil barrel.
    Captain is right, find the right ammo. Don't run junk. But don't try too hard to squeeze sub MOA out of it. SIG didn't built to achieve that. However, despite that, this rifle, more often than not, has better than average black rifle accuracy, but not as good as a med profile AR. But plenty good enuf within 200 yards.

    There is a better trigger available from Shooting Sight
    SIG 556 / 551-A1 Sear/Hammer

    But, if your sear isn't bad, you can improve by backing the plunger back to trigger stop

    I wouldn't tighten or shim anything, this thing runs loose just fine.
    Keep your piston clean.
     
  4. CPN

    CPN New Member

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    Art's hammer and sear setup are excellent and he's a great guy, but I found that I didn't need his setup. The factory items on my 556R are unbelievable. Instead, I bought this trigger spring kit from Matt in Germany:
    55x_TriggerSpringKit_Installation_2012.pdf

    I also got the proper die for the trigger spring plunger and cut enough thread onto it to make it effectively an overtravel stop. Now the trigger is truly unbelievable. Easily the best 'stock' trigger I've run across on a battle rifle.

    Somewhere on this site a fellow figured out that instead of spending money on that stupid 'Zurich Wedge' sold elsewhere, he found a Kohler faucet seal that fits perfectly in your lower, works better and costs about a buck. It looks like this:
    556R Kohler 'AccuWedge' Seal.jpg

    And I figured out that to cure the fore grip rattle, I found a proper high temp silicone O-ring that I put right behind the gas block, like this:
    556R Handguard O-Ring.jpg

    Now, with Matt's shim washers on the front pivot pin, my 556R doesn't have a shake or rattle anywhere.

    And this is the final product:
    556R.jpg
    556R2.jpg

    The last items for me are a set of Samson BUIS and Griffin Tactical's charging handle for a little extra hand clearance from the EOTech.

    Sorry I couldn't figure out how to post the photos here. I haven't done this in awhile and didn't want to expend the brainpower to figure it out again.

    Hope this helps somewhat and, good luck!
    I love my 556R. It's easily a 1.5 MOA gun with Golden Tiger ammo. When my shooting gets better, I'll try the couple of boxes of Lapua ammo I have stashed away... after that I'll roll my own and see how it goes.

    As it is, it's pretty damn good for an AK...
     
  5. Iamscotticus2

    Iamscotticus2 New Member

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    Very nice work.
    Did you contact Matt?
    I haven't seen him in this forum for a long time.
     

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