308 ar-15?

Discussion in 'AR-15 Discussion' started by fa35jsf, Apr 28, 2014.

  1. fa35jsf

    fa35jsf New Member

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    Quick question, if I wanted to build my next AR-15 and chamber it in 308, is that possible? I know that AR-10 is chambered in 308 but those are heavy.
     
  2. robocop10mm

    robocop10mm Lifetime Supporting Member Lifetime Supporter

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    The AR-15 will not take a cartridge as long as the .308. AR-10 is the only option
     

  3. fa35jsf

    fa35jsf New Member

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    Ok. Makes sense. So would I still need the heavy AR-10 BCG and an AR-10 upper OR does an AR-15 upper fit on a 10 lower with a 308 bolt?
     
  4. wknight40

    wknight40 New Member

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    I believe on the the AR15 platform the closes would be the 7.62X39. The 308 is 7.62X51.

    The usual round for the AR 15 is 5.56X45. The 308 is longer than the 5.56 round and will not fit the length of the mag well. The 7.62X39 being shorter will fir the mag well.

    I have read some post's the the 7.62X39 does not fit the mag well properly as it prefers a curved magazine such as what is found on the AK-47.
     
  5. fa35jsf

    fa35jsf New Member

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    OK. Thanks for all the advice.
     
  6. Triumphman

    Triumphman Active Member

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    All 308s are considered an AR10 or whatever name the manufacturer gives to that model, to distinguish it from a "true" AR15 to keep from confusion.
    This is due to the larger Receivers/Magazines/Barrels/BCGs that are required. They won't interchange with AR15 platform.

    Just like any Bolt Action 22Magnum might look exactly like their counterpart 22LR from the same Manufacturer, but they're different and 99% of stock components won't/can't interchange.
     
  7. sweeper22

    sweeper22 New Member

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    An AR10 build can be quite similar to an AR15 build, but requires a bit more homework as well as 308 specific parts.

    The two are not interchangeable. And for that matter, many AR10/308 parts and pieces are not interchangeable the way AR15 parts are from one brand to the next...which is where the 'homework' applies.

    In many cases, buying a complete AR10 is the safest bet.
     
  8. Txhillbilly

    Txhillbilly Active Member

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    That all depends on the configuration of the "AR-10" platform. My DPMS LR-260H is lighter than my RRA 20" Varminter AR-15.
    The DPMS has a 20" HBAR style barrel,and the RRA has a 20" Bull barrel.
     
  9. sandog

    sandog Member

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    If you want to stay with the lighter smaller AR-15 platform, one that comes close to the .308 in power is the .30 Remington AR. It will shoot 150 grain bullets at 2500 +, and lighter bullets a bit faster. But I believe only Remington makes the uppers and complete rifles, and the fatter round won't work with standard 5.56mm magazines, so your selection of magazines will be slim. I don't see the .30 Rem AR listed on Remington's R-15 page, only the .223 and .204, so maybe they dropped it. Too bad as it is an awesome round. I guess not enough people discovered it, but someone could locate a used one. I would want one but would reload for it as I haven't seen much factory ammo around. Something like the .300 blackout would be the obvious choice for an AR-15 in .30 caliber, but the round is way short of the power of a .308.
     
  10. JonM

    JonM Moderator

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    Only the colt le901 will do what your looking for.

    Scar17s is a great lightweight 308. Fully loaded WITH optic my scar comes in at 11 pounds including storage compartments filled with tools and parts...

    I could shave off some weight by just using irons or a aimpoint and emptying the storage out. I've done some mods to it and its far from stock.

    [​IMG]

    Since that pic I've removed the factory sights and replaced them with magpul mbus sights. Saving another 3 ounces.
     
  11. purehavoc

    purehavoc New Member

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    Do your research if you intend on building on in .308 . They are not like a Mil Spec AR15 where all parts are interchangeable. Some .308 parts of one manufacturer may not fit another manufacturer . Some uppers wont fit other lowers, some have specific mags that only work with their brand. Barrel nut threads are different between different brands, some have different height uppers and free float hand guards may not match up exact to some brands . DPMS even has 3 different rail heights .
    In all honesty this platform is easiest to purchase a complete rifle and in most aspects its cheaper to buy a complete than build your own in the .308 platform .
    I bought complete and switched up to the parts I wanted . People really swoop up take offs and used .308 parts pretty quick so I recouped most of my money switching parts . Im not trying to steer you away from building but it can be a expensive mistake if you purchase the wrong parts. This one weighs in a little over 11# as pictured and most of that weight is from the PRS stock and buffer tube. The stock and buffer tube alone without buffer and spring weight 1.9# . I could knock off a 1 1/4 # going to a MOE stock and buffer and get it at that 10# range if I really wanted to . I have the PRS set up for me and the extra weight isnt a big deal to me . You can shave weight if you choose to do so . I could have used aluminum scope mounts instead of steel Leupolds . I will say this with the extra weight on this rifle it has very little recoil

    [​IMG]
     
    Last edited: Apr 29, 2014
  12. Eagle1803

    Eagle1803 New Member

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    Jon, nice gun.who makes that scar17?
     
  13. nchunt101

    nchunt101 New Member

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    FN...........
     
  14. fa35jsf

    fa35jsf New Member

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    Ok. Well after all this I don't think I am going to be building an AR 10. Maybe buy one one-day.

    My initial thought about my next AR-15 build was this:
    I would like to have either a 18 or 20" barrel to take advantage of higher velocities and smoother operation of the rifle gas system. The profile I was looking towards was at least mid weight or government. The barrel would need to be chrome lined at a minimum but I would really like one of the FN machine gun barrels from PSA if I could afford it.

    Obviously a rifle length rail capable hand guard. At this point I don't really care what brand. I am not really going to mount much on it but I like the option of putting something on later if I so wish.

    Probably a multi position collapsible stock that is a little bigger than the standard style M4 stock. Been eying some Magpul stuff.

    Up top I am going to put either a nice red dot with a flip away magnifier like I have on one of my other AR's or perhaps a low powered scope (3-5x or so)

    Lastly I am going to give the whole thing a camo paint job.


    SO.... The whole reason I was asking is I was contemplating building something with a little more power behind it.



    Sent from my iPhone using Firearms Talk
     
  15. purehavoc

    purehavoc New Member

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    Most everything is bigger and heavier on the .308 versions


    [​IMG]
     
  16. Overkill0084

    Overkill0084 Active Member

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    .300 Blackout might be worth a look. Works with standard mags and little in the way of changes other than the appropriate barrel. Ballistically, it's in the neighborhood of the 7.62x39. Much depends on your intended use as to whether it's worth your while.
    It's on my list of things to do at some point.
    Biggest downside would likely be ammo availability and cost for those who don't reload.
     
    Last edited: Apr 29, 2014
  17. JonM

    JonM Moderator

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    Fnhusa but all civy scars are imported from belgium and made 922r compliant here with .mil parts and barrels. My scar is heavily modified.

    16" barrels work awsome with 308. Max effective realistic range is about 800yards it can reach out to 1000 but its really iffy. Max range is about 2000yards but your just poking it out there trying to hit a acre at that point.

    16" vs 20".your giving up 50ish fps for a huge weight savings and its not going to break or make any shot.

    My wife uses a 22" savage 10 in 308 she can poke hers out to 900-1000 but its heavier gun with less capabilty than mine.

    A while back i went through the proccess of researching out a semi 308 stumbled across the scar17. Top choices. At the time were the colt 901 and larue obr.

    The scar17 has a cold hammer forged chromed barrel and chamber. Monolithic reciever. Tuneable gas system. Simple rugged bcg. And tons of available aftermarket options. Fairly easy to get spare parts from several vendors and from fnh themselves.

    While stock they use bulky mags designed at the end of ww2 for the fal i converted mine to using pmags.

    If i didnt go scar17.i would have gotten the colt 901
     
  18. jjfuller1

    jjfuller1 New Member

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    so you wanted something with more power than a 223.. the .300blk, the 6.8spc, the .458socom. there are a lot of higher powered cartridges made that can be had. try out one of these or at least look into them. they all use the standard 15 lowers and the upper and mags are all that need to be changed. i just built my second 6.8spc. i love the exrta power i get from it. trying to take a deer with it next fall, this last year i saw nothing legal for me to shoot at
     
  19. fa35jsf

    fa35jsf New Member

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    6.8
    I heard that the problem with 6.8 is there is 3 different calibers called 6.8 and they are not compatible. Is that true?


    Sent from my iPhone using Firearms Talk
     
  20. Txhillbilly

    Txhillbilly Active Member

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    The 6.8 SPC is a great caliber choice for the AR-15 platform,as is the 6.5 Grendel. The 300 Blackout was designed mainly for shooting with a suppressor,and doesn't really have the ballistics that the other's offer.