20'' or 24'' AR-10 Barrel Accuracy ??

Discussion in 'AR15/10 Rifles' started by bigbuck, Mar 22, 2013.

  1. bigbuck

    bigbuck Well-Known Member

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    A good friend of mine purchased an Ar-10 with the non fluted target barrel he likes the 16'' barrels . I may trade with him , he is going to let me shoot it as his is used . I want to make sure it is in good condition so I plan on throwing a scope on it and shooting some 3 shot groups with it at 100 yards . I only have store bought bullets . What kind of accuracey should I exspect ? I dont want to trade if it is shot out .

    I plan on shooting this rifle out to 1000 yards coyote hunting,deer hunting maybe to 800 yards. Will this barrel work ?

    Another question . My bolt and barrel is brand new so could I just trade my barrel for his barrel and keep my new bolt ?

    Thanks for any advice . I dont know anything about these styles of rifles ...
    But I have been bitten by the black rifle bug:D
     
  2. woodnut

    woodnut Well-Known Member

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    let me guess, it is a 308?
     

  3. bigbuck

    bigbuck Well-Known Member

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    yep :)
     
  4. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    And stop! need more info, there is NO STANDARD at all for AR variants in calibers other than 5.56mm NATO. So given that info we can proceed.
     
  5. bigbuck

    bigbuck Well-Known Member

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    Not sure I understand what you mean ?
    What kind of Info are you looking for?

    Make Panther Arms .308 ...
    Will eventually hand load 175 SMK.
    but right now I have 3 different kinds of factory Ammo One box is suppose to be a match load.
    Let me know what Info you need .
    I am looking for a ball park estimate like 1'' Moa at 100 or 1 1/2 Moa at 100 yards. I really have no Idea. I guess if I put up a 2'' orange sticker on a sheet of copying paper 8 1/2'' X 11'' and I have 3 shots scattered all over it then I will pass on the trade .
    As for the bolt , I need to know if I can switch my new bolt out of my upper and run it on the target upper that I would be trading for.
    Thanks
     
  6. woodnut

    woodnut Well-Known Member

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    Once again, we need to clarify. Are you wanting to trade an upper or just a barrel?
     
  7. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    I try an relate these fact to everyone in my post, in the world of AR rifles there are some constants or Standards. In the AR world Armilite Rifle, AR is a name owned by the Armilite corporation AR15,AR10, SPR (if you don't own an Armilite technically you don't own and AR10). There is a standard for the M16 family of rifles called "MIL-SPEC", it's a manufacturing, material, and size standard. Some companies adhere to this, some exceed it and some claim it but do not provide it (marking tool). This standard on the M16 family in no way apply's to the larger variants of the Armilite AR system. What all this means is if you own one of these rifles it may or may not be interchangeable parts wise with a rifle from another maker. Some of them use different magazine designs and still others use different upper and lower receiver designs, not to mention bolt carrier groups. There are three patterns that I can think of off the top of my head the Knights-sr25, DPMS and Armilite.

    This is why I asked the question I did, you may not even be able to swap uppers. If your rifles are incompatible with one and other you cant swap. The other poster mentioned the barrels, this is because that "should" be the one common part. You may be able to swap barrels.

    All this said the buffer spring and buffer you have in your rifle will have to be swapped with his rifle and this is only possible if you have the same length receiver extension. So what I need to know is what you have and what he has, what stocks you guys are using etc. As for the barrel accuracy you may see an improvement due to the weight of the system, however the 308 Winchester is not sensitive to changes in barrel length. In my opinion the added weight of the barrel you are talking about is not worth it, as the 16" barrel with a 175g SMK will get past 1000m before it drops through the trans sonic range.

    If you really want a different barrel buy one, in the length and profile you want. Rainier arms is a good source.
     
  8. bigbuck

    bigbuck Well-Known Member

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    Sorry guys for not giving enough Info.
    I understand what yall are talking about now (I'm a little slow):)

    I have a DPMS. Oracle with a mediul weight 16'' barrel.
    MY stock is a collapsable stock .
    My buddys stock looks more like a rifle stock on a bolt gun.
    My buddy has a DPMS.

    I want to trade him barrel and stock but I would like to keep my brand new bolt . What would you guys do ? My friend says we can simply change complete uppers which is what I thought I would do but I like the idea of keeping my new bolt.
     
  9. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    Call DPMS and ask about the bolt, they should be the same and that should be a non issue unless its a generational thing. The stock is an easy fix those parts can be swapped in about 20 min. I am not personal aware of any difference in the two rifles that would impede your swapping uppers. However ask DPMS on the phone.
     
  10. bigbuck

    bigbuck Well-Known Member

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    Okay I will give them a call .
    Thanks for the help and advice.
    You mentioned earlier that I should keep the 16'' barrel I didnt think I could obtain the best MV for 1000 yards or 800 yards . I may be wrong but I thought the additional inches in barrel length would help . I guess what I want is a sniper type auto rifle. Is the weight the main reason you would stay with the 16'' barrel ? What lenght barrels is the military using on the SASS rifles ? Or Sniper rifle in the .308 AR configuration ? Do you know what grain bullet are they shooting ?
     
  11. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    They use the Knights Armaments M110 here is a link, there are two versions. SASS is what the program was called to adopt a rifle (even though everyone new knights was already chosen). These rifles were not envisioned to provide precision fires past 800M. They were chosen for rapid engagements and compact handling in urban environments.

    The standard match round for the M110/M14 is the LR118 round, It fires a 175g SMK behind R15 in LC brass (I believe they have now switch powders). The barrel length is not as key in the 308 as the twist rate and the bullet fired. I believe the general rule of thumb is 50 fps for every inch of barrel how ever the 308 is an exception.

    The other precision fires platforms with in the military the M24 and M40 use a 24" barrel. However there was a program fielded a few years back by the marines in which 20" barreled versions were use with overwhelming success. The Army has chose to upgrade there M24 to 300 win mag and use the M110 for closer stuff.

    If you want to use the search function over at M4c "KevinB" "sinister" are names to look for. Kevin is military sales rep for knights and sinister is a seal, with lots of hands on experience with these platforms. If you decide to join the forum be warned that they are not fond of certain companies and will openly ridicule anyone.

    Its also important to note at this point that your rifle is not a bolt gun and has a floating firing pin. Whats this mean? when you close the bolt the firing pin actually impacts the primer, this can cause a out of battery detonation of your round destroying your weapon and maybe you. The military use a primer with a thicker cup to account for this (CCI #41). Next time you chamber a round extract it and look at the primer you will see a dent ,scary! Additionally as I mentioned in the beginning, your rifle is not a bolt gun. This means you have to be super careful with ammo selection NO SUPER PERFORMANCE AMMO, and when you reloading you need to reload for a gas gun that means not all powders are OK to use in your rifle just because they are in the manual for 308 Winchester.

    God its so much info and I did not come by it all over night and this is by no means all of it, but I hope I'm helping some. Also I like short barrels 16" will get it done with the right bullet, I would never go longer than a 20". If you swap and find out you want a shorter one you can have it cut down, but then you will also need your gas port corrected or your rifle will not work there is also the possibility in that case you will need to swap buffer or spring, this is just FYI info.

    Jon
    Military | Weapons | Accessories | Knight's Armament Company

    Also look through this and see if you can get any ideas.
    http://www.m4carbine.net/showthread.php?t=65306
     
  12. bigbuck

    bigbuck Well-Known Member

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    Thanks for the links and Info .
    I appreciate all of the knowledge you have shared this really helps .
    I dont want to be a bother with too many questions but do you know what brand of powder the military used with the 175's or what powder should I purchase to use with my gas gun? Thanks
     
  13. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    It used to be R15, I wrote it you just missed it.
     
  14. bigbuck

    bigbuck Well-Known Member

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    Ooops I'm going to send you a Pm in a moment.gun)