AR-15 Accuracy Help

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by bookworm, Mar 28, 2009.

  1. bookworm

    bookworm Well-Known Member

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    Started with a standard Bushmaster A2 Carbine (16" heavy barrel) that I bought 10 years ago...but hardly shot.

    I wanted to turn it into a varmint rifle and start shooting it more so I put on a flat top receiver, free floating tube, Vortex scope, and adjustable gas block - all else is stock.

    I was very disappointed today when I turned in 2" - 3" groups at 100 yds. I was shooting PMC factory ammo - 55gr. FMJ BT.

    I was hoping that this rifle would shoot something close to moa (understanding that I might not quite get there with non-match ammo and a standard chrome-lined barrel). Maybe that was too much to hope for, but 2-3 moa...really?

    What advice can you give to get me down into the moa region?
     
  2. preacherman

    preacherman Well-Known Member

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    what barrel twist?

    maybe try a heavier bullet?
     

  3. canderson

    canderson Well-Known Member

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    I would look at the twist rate and try to match bullet weight with twist. Also if you can find some different factory ammo, try several different brands.
     
  4. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    I own 4 ARs and every one of them is more than capable of MOA. Get Black Hills ammo blue box is fine. Chances are your twist rate is 1-9 and the 55g bullets will work fine.

    ARs are silly a lot of things will affect the accury.
     
  5. preacherman

    preacherman Well-Known Member

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    Get a "Rock River"... just joking... I love'em all!

    Seriously, after testing different ammo, would look at a different barrel
     
  6. bookworm

    bookworm Well-Known Member

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    Thanks for all the replies. The barrel is 1:9, so in theory the 55gr should be ok. I guess I'll try some better ammo and see what happens.

    On the "new barrel" suggestions, I'll need a new hand guard and gas tube as well as getting the bolt head-spaced...anything ellse? Would you just get a whole new upper?

    I was going to attach some images, but I guess I don't know how...I'll figure that out and come back later with pics.
     
  7. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    I have never seen an AR that would not shoot with the right ammo shooter combination.

    Have you had some one else shoot it?

    ARs are finicky I would have a AR specific gunsmith look it over before I scraped it.

    Will you post some pics of the bolt and bolt carrier with close ups of the gas key? Have there been any feeding issues?

    I will post your pics or teach you how to if you like just pm me
     
  8. MN Hunter

    MN Hunter Well-Known Member

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    I agree try some different factory ammo or start reloading. My (7) rifles all seem to like varget powder - some shoot better with 55 grain winchester psps - some like the barnes varmit gernades. Factory triggers ca be a bit rough. You may want to change out the triggers - mine all have JP's in them. That should help. One more place to check - is the hinge pin tight or is there a lot of play in it? There is a wedge you can get that will take up the slop when the action is closed.
     
  9. bookworm

    bookworm Well-Known Member

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    I plan to start reloading soon. I was planning to begin with my 300wm and thought I had some time before needing to start loading the .223 since I still have a few hundred rounds of the PMC. I guess I might have to re-think that timeline a little bit.

    Can someone recommend a factory load I could purchase that has proven to be pretty reliable in AR's?

    When you say "hing pin" do you mean the two main pins that connect the upper and lower halves of the gun? If so, they are both very tight. So tight that you need a punch to get them out.

    Yes the trigger is very rough. There is a ton of creep and it is pretty stiff overall. The creep is interesting though - it almost acts like a multi-stage trigger. I can squeeze the creep out of it and know that I'm right on the edge of breaking. As such I'm able to predict when the trigger will break pretty well. I could be wrong but I don't think that had a major affect on my shooting. Are you happy with your JP, and what pull weight do you have it set at?

    Below are the first pics I promised...I'll take some pics of the items ICANHITHIMMAN and respond shortly...thanks again for your willingness to help.

    [​IMG]

    [​IMG]
     
  10. bookworm

    bookworm Well-Known Member

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    ICANHITHIMMAN,

    Thanks for the questions. I've heard good things regarding the accuracy of these rifles, so needless to say I was disappointed with yesterday's outing.

    I have not had anyone else shoot the rifle for groups yet - it's a good idea. Yesterday was my first day out with the rifle in its current configuration.

    I have not had any feeding issues. Yesterday was the first day with the adjustable gas block, so I did short cycle the bolt a couple times as I was adjusting the block to the right setting. According to the directions this is normal. Other than that the rifle has never had feeding issues.

    Here are some pics of the bolt assy. Let me know if there is a particular angle that you want me to take.

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
  11. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    Hay nice rig I only asked for the pics to see if maybe you have a miss alligned gas key is there any metal whear on you bolt carrier anywere?

    Got one tip for you when you start to reload for the AR and not everyone agrees on this but....... Get the small base X dies I use them for my M1A and my ARs.

    +1 for Varget like MN Hunter said I shoot a reproduced military load in my LMT ussing H335 and speer bullets.

    The carrier and bolt look fine veary well staked and there is no were around the gass key it does not look as though you have shoot it much.

    Who made the upper again?
     
    Last edited: Mar 29, 2009
  12. bookworm

    bookworm Well-Known Member

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    Thanks for the reloading tip.

    I think the rifle only has a couple hundred rounds through it...maybe a little more, but not much.

    I started with a stock Bushmaster, but recently had a flat top upper receiver put on but kept the same bushmaster bolt assy, barrel, etc. The upper receiver is made by Mega Machine.

    Unfortunately I did not establish a baseline accuracy with the rifle before the modifications were done. Then I at least would know if the rifle was shooting poorly with this ammo before the mods were done...and not a result of the mods.
     
  13. Kevin Thomas

    Kevin Thomas Well-Known Member

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    Hey Bookworm,

    No reason at all to be disappointed here. With the 55 grain FMJ factory stuff running 2-3 inches, you're right in what the ammo is capable of. The FMJ is pure military fodder, and accuracy is a purely secondary consideration. These bullets, from virtually every maker, are hands down the most inaccurate projectiles you'll ever lay a hand on. Use them for plinking, use them on cans, but don't ever expect them to shoot accurately. Now, the AR platform itself is capable of some truly astonishing accuracy. Most of the match built guns are easily capable of honest, consistent 1/2 MOA if it's fed decent ammo. Other than that, there are a few tricks to building these guns for accuracy, but they're very well understood, and there are many good smiths out there who specialize in the ARs. Three of the best (in no particular order) are Frank White at Compass Lake Engineering, John Holliger at White Oak Armory and Derrick Martin of Accuracy Speaks. I've used guns built by all three in the Natuionals (Camp Perry) and had excellent results from all.

    Reloading for an AR, (any semi-auto, for that matter) is a form of advanced handloading. There are some specialized concerns that need to be addressed, but again, there's roadmaps out there to follow. Sierra's manual has a chapter on reloading for Service Rifles, and Glen Zediker has at least three complete books that deal with reloading match grade ammo for these guns. John Feamster (Precision Shooting Magazine) and Derrick Martin have both done books on competitive ARs, and each has sigificant amounts of info about reloading for these guns. Might check with Sinclair International, as I believe they stock all of these. Don't hesitate to ask for help with this stuff, since there's more than enough folks around who can be of assistance!

    Hope it helps,

    Kevin Thomas
    Berger Bullets
     
  14. bookworm

    bookworm Well-Known Member

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    Hi Kevin,

    Thanks for taking the time to share your thoughts and insights - very much appreciated.

    I have no delusions of this rifle (or me for that matter) turning in 1/2 moa performance, but I do hope to get it sub-moa if possible. I don't plan to compete, but would like to do some longer range coyote and varmint hunting with it.

    I'm new to reloading, but have just purchased some 190gr VLD's for my 300wm to work up. In light of my recent outing with my AR I'll be researching some good .223 hunting loads that will work well in my rifle - thanks for the book references. Do you personally have any Berger bullet and powder combos for a rifle like mine that might be a place for me to start?

    I've been hunting and "play" shooting my whole life, but this long range shooting/hunting and reloading for accuracy is new to me...so I'll take all the help I can get!

    Thanks,
    Darius