Considering an AR build

Discussion in 'AR-15 Discussion' started by Angry_bald_guy, Jul 28, 2010.

  1. Angry_bald_guy

    Angry_bald_guy Lifetime Supporting Member Lifetime Supporter

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    Ok, I'm fairly new here and the only gun I have owned so far is the 1911 that I currently have. I've been looking at building an AR-15 for a SHTF situation and was wondering about the .308 chamber for it. I have a few questions about it and would like to use your experience here.

    First of all, will a standard AR-15 lower work with a .308 upper?

    Second, will a standard AR-15 mag work with .308 win rounds?

    Third, what is a gas piston assembly for an AR-15 and what does it do?

    Last, what is the difference between an AR-15 and an AR-10?

    Thanks for your time and help.
     
  2. spittinfire

    spittinfire New Member Supporter

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    The 308 will not work on an AR upper nor can it use standard AR mags. The 308 is an AR10. It's the same basic platform but due to the longer cartiridge you need a longer bolt cycle. There are commericial loads such as the Remington 30 AR that are .30 and designed to work on an AR15 platform and mimic 308 balistics but a tat pricey.

    The AR is gas operated which means it uses the hot, pressurized gas from the discharged round to cycle the action. Most use a tube which direct the gases back to the bolt and push it to the rear. I personally can see no reason to go with a piston system unless you just want it.

    Does that help? There are people here who know a lot more about ARs who will be along shortly if you need more info.
     

  3. mjkeat

    mjkeat New Member

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    THis is it in a nut shell ^^
     
  4. Dillinger

    Dillinger New Member

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    1) As indicated above, that would be a negative.

    2) Again, as indicated by Spitty, negative.

    3) The gas piston system is an "improvement" to a problem that doesn't really exist if you take care of your weapon. The gas piston system takes the place of the gas tube system and makes your AR run more like an AK. The gas pressure is harnessed at the muzzle end of the weapon and forces a piston backwards to cycle the action. In the current design, the gas itself creates the expanding pressure to cycle the action. The piston system is more reliable, if you are prone to dragging your weapon through 60 yards of mud and wet concrete before shooting it, but it is not as accurate as the standard gas system. It's a trade of, a little more reliable for those that abuse their weapon and a little less accurate. So what you have effectively done is created a really expensive AK ( in my opinion and that of others I know :) )

    4) As indicated above - the AR-10 is the classification for a larger sized, big brother version of the AR-15. There are tens of cartridges that can be custom made for either model, but it comes to case size. For the larger rifle calibers like .308, you need AR-10 parts. For smaller applications like the 5.56/.223, you need the AR-15 parts.

    Hope that helps!

    JD
     
  5. TheDaggle

    TheDaggle Member

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    If money is a factor, you may want to go the 5.56 route. Ar 10s are much more expensive. I don't know what .308 ammo costs, but I bet its more expensive, as well.
     
  6. canebrake

    canebrake New Member

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    First build? Don't complicate it!

    I would go with a RRA complete, direct impingement, 5.56 Nato upper and build the bottom end.

    Rock River Arms: .223/5.56mm Upper Halves

    I went with a quality, multi-cal, billet, stripped lower. When you start with this good of a foundation it opens all sorts of upper swap-outs.

    Rainier Arms, LLC™ Mega Billet Lower - GTR-3S

    I highly recommend Rock River Arms and Rainier Arms for your AR build parts.
     
  7. Angry_bald_guy

    Angry_bald_guy Lifetime Supporting Member Lifetime Supporter

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    Thanks for clearing everything up everyone. I am already getting a .308 bolt action and was looking to keep similar ammo stocked instead of changing calibers, but I'll give the AR-15 some thought instead.
     
  8. dog2000tj

    dog2000tj New Member

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    Why not get/build and AR15 and an AR10? :D
     
  9. Angry_bald_guy

    Angry_bald_guy Lifetime Supporting Member Lifetime Supporter

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    That's what I'm leaning towards... But I was hoping to do an AR10 first time out.
     
  10. dog2000tj

    dog2000tj New Member

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    Well you will have loads of choices if an AR10 is indeed the way you go. All the big names make a lower and more and more are coming out with complete rifles. ;)
     
  11. spittinfire

    spittinfire New Member Supporter

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    Angry, I built my first AR in 223 and I don't even like 223. Now that I have it I want to keep the upper and find a new upper in a different caliber but that won't happen for some time. I also wouldn't mind rounding up an AR10 to add to my collection.
     
  12. Angry_bald_guy

    Angry_bald_guy Lifetime Supporting Member Lifetime Supporter

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    I was looking at this. I'd be stupid not to go this route for building it. Everything assembled and all I need to do is pin the lower to the upper.
     
  13. spittinfire

    spittinfire New Member Supporter

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    At least build the lower. It's not hard and very rewarding.
     
  14. Angry_bald_guy

    Angry_bald_guy Lifetime Supporting Member Lifetime Supporter

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    I can't find a .308 lower for cheap enough to justify not going with that though.
     
  15. CHLChris

    CHLChris New Member

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    It has 1-10 twist. In AR-15 language, that would be a twist rate intended for, like, 50 grain .223 rounds. But .308 rounds are often closer to three times that size (150 grains). What is the conversion equation for which twist rate(s) Angry would want to look for?
     
  16. dog2000tj

    dog2000tj New Member

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    Not a bad price for the upper and lower. If it were me I would have nothing to do with the adjustable stock - having to swap that out might make assembling your own lower more attractive. For right around $1100 you can find quite a few deals on DPMS LR308's in different configurations. Check out their site - DPMS: AR-15 Rifles, Parts and Accessories. - see if you can find what you like then shop for that. I would bet a local dealer in your area can order whatever setup you want and then add on the transfer fee.
     
  17. Angry_bald_guy

    Angry_bald_guy Lifetime Supporting Member Lifetime Supporter

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    Yeah, but I can take the stock off and sell it... That stock and a standard AR-15 stock are interchangeable, right? If so, I still can't beat the price. The cheapest I've found a lower is 200, and it's on back order...