Lightweight AR: Where is the weight?

Discussion in 'AR-15 Discussion' started by CHLChris, Nov 14, 2013.

  1. CHLChris

    CHLChris New Member

    2,523
    0
    0
    I'd like to get a lightweight AR. Where is the biggest weight savings? There is not much information on weights of various parts and unless I am comparing complete rifles, I'm having a hard time being able to figure out what to choose to keep it light.

    Often "Lightweight" AR's (BCM, RRA, PSA, etc) are basically a pencil barrel and that's the only modification.

    Forged/Billet lower versus Polymer lower or upper: Big difference in weight?

    Carbine system versus midlength system: Savings here?

    Lightweight handguard (some are very expensive) versus a simple Magpul MOE

    BTW, I plan to go with just iron sights and maybe a Crimson Trace rail master laser. That'll help the weight, too.
     
  2. Mercator

    Mercator Active Member

    11,342
    16
    38
    The biggest weight saver would be a composite construction such as in the Bushmaster Carbon. Second, a thinner barrel (aka pencil), especially in a 20" rifle. No carry handle. Carbine length, yes. Probably some little things, but basically this is it. The iron sights could be plastic too of course.
     

  3. MisterMcCool

    MisterMcCool Well-Known Member Supporter

    13,080
    642
    113
    Carroll Shelby built a career by reducing weight in sportscars. He eliminated anything unnecessary and lightened everything else.

    Mine weighs about 4.5 pounds. Bushmaster carbon fiber receivers and superlight barrel. Ace ultralight stock. No forward assist. No iron sights. No weighty rails.
    The bolt and carrier are the heaviest parts. But they are centered so it helps the balance.
     

    Attached Files:

    Last edited: Nov 14, 2013
  4. Garadex

    Garadex New Member

    1,267
    0
    0
    Holy crap, I've got .22's that weigh more than that.
     
  5. sweeper22

    sweeper22 New Member

    2,706
    1
    0
    A lot of that doesn't really suit my tastes. And yet, I find your rifle pretty damned cool. Wouldn't mind taking a swing at a similar ultralight build at some point. Weightlessness can be quite adventageous. Very cool setup!

    7lbs is sort of what I consider the 'vanilla' weight for my ARs. I prefer light. I have a 14.5" BCM middy build that weighs about 6.5#...that's with forged alloy lower, BCM M16 bcg and ambi CH, BAD lever, CTR stock, Vortex RDS and MBUS...so I managed to get everything I desired and still keep it trim.

    [​IMG]

    My featherweight rifle is a KelTec Sub2000. 17 or 33rds of 9mm, folds in half, 4lbs (unloaded).
     
  6. JonM

    JonM Moderator

    20,110
    19
    38
    I think going carbon poly you give up too much in rigidity ad strength for the weight reduction.

    Forged upper and lower Ff tube made thin and light with magpul mbus sights pencil barrel mid length gas system lightweight magpul moe stock or m4 milspec stock is good as it gets

    Weight has advantages especially when you want to shoot fast and accurate. Weight soaks up recoil. Lessweight equals more recoil and muzzle jump meaning slower less accurate fire.

    A happy median to me is around 6-7 pounds in a ar15
     
  7. sweeper22

    sweeper22 New Member

    2,706
    1
    0
    Barrel- Pencil barrels are great, and 14.5" middies can work well if set up correctly. Carbine gas is fine too, and you can keep things pretty light with a 16" pencil midlength.

    Lower- Contrary to popular opinion, I would trust a polymer lower. But I would not build one. They can split/stretch in spots when hammering in pins and such (it's happened to me). But if together without flaw, I believe they'll stand up to a fair amount of use. I just don't like them because they look cheap.

    BCG- Minimal weight variance, and it's centered weight. Buy a good M16 with a C158 bolt. Reliable cycling trumps weight 8 days a week.

    Handguard- Keep it simple. Magpul MOE is a great option.

    Stock- Can be a biggie when it comes to overall weight as well as balanced weight. Standard milspec stocks are light. MOE is also an option, and CTR if you want it to lock into place.

    When trying to go lighter and lighter, it quickly becomes a matter of trade-offs. My car would be a lot lighter if I ditched the spare tire, bumper, and back seat...and after all, I rarely use any of them...you get the point, LOL.
     
  8. CHLChris

    CHLChris New Member

    2,523
    0
    0
    Jon suggested mid-length. My primary AR is mid-length, which I find perfect for the platform. However, in terms of weight, doesn't the carbine help at least a bit?

    The Bushmaster Carbon-15 is definitely appealing! So is the GWACS CAV-15 lower (one-piece complete polymer lower)!

    But this is why I ask the main question. If the biggest amount of weight savings is in the barrel and choices on the upper, then why bother with polymer receivers? I really don't know where the weight is.

    Any other ideas?
     
  9. MisterMcCool

    MisterMcCool Well-Known Member Supporter

    13,080
    642
    113
    The barrel and furniture are the majority of weight. Everything else is a compromise with minimal reduction. Barrel mostly.
     
  10. CHLChris

    CHLChris New Member

    2,523
    0
    0
    BTW, my purpose for this build idea is that I want/need an AR for my wife who is very weight-sensitive. Anything I can lighten I want to consider it.

    What is better for weight: A standard triangular front sight post or a railed gas block (which would require a metal BUIS anyway)?
     
  11. MisterMcCool

    MisterMcCool Well-Known Member Supporter

    13,080
    642
    113
    I have a spare low profile gas block you can have. It has no rail. It is a VLTOR stainless for pencil barrels.
     
  12. Mercator

    Mercator Active Member

    11,342
    16
    38
    Well done. This a no BS rifle. Less is more.
     
  13. sweeper22

    sweeper22 New Member

    2,706
    1
    0
    Poly lowers are lighter. Barrel, handguard, lower, and stock are the primary variables apart from accessories.

    It's really just a case of what concessions you're willing to make. If you simply want the lightest functionally reliable platform...poly lower could well be the answer. Carbon Bushy, GWACS, NFA might be ideal. Handle the GWACS first though. It has a slim grip that can be a little odd and they're really tight fits to build on.

    Most of these streamlined options will be less prone to quick precision, as would be a micro carry pistol. But that doesn't mean they can't meet your purpose. I find that my $400 KelTec S2K is a nice lightweight and portable (if need be) option.
     
  14. CHLChris

    CHLChris New Member

    2,523
    0
    0
    Thanks for the offer, MisterMcCool, I PM'ed about it.

    I agree that the GWACS lower is probably not worth the weight savings. A billet lower with an MOE stock and we're probably near the same weight with a much stronger lower.
     
  15. sputnik1988

    sputnik1988 Active Member

    2,883
    2
    38
    This isn't the lightest available, coming in right around 6 pounds or a hair less with a birdcage flash suppressor and an aluminum stock, run a fiber light car stock and your talking about 5 1/2 pounds. thats still pretty light and it's just freaking cool.

    you could even run a flat top and save a bit more, but that A1 upper just makes the rifle.

    Unfortunately with an 11.5" barrel it is an NFA item

    XM177e2, predecessor to the M4
     

    Attached Files:

    Last edited: Nov 15, 2013
  16. Ibmikey

    Ibmikey Active Member

    457
    30
    28
    As noted the barrel is the greatest weight in an AR, you can save a few ounces on the BCG but it is pricey and needs to be mated with other parts. The small round hand guard with or without shields is lighter than others and a fixed carbine stock is just a tad lighter than many others. Leave optics off and use poly sights with your new light weight build...oh you might add a little weight with a Rainier XTC compensator (or the like) to keep your light weight from having much recoil or muzzle rise.
     
  17. AgentTikki

    AgentTikki New Member

    3,496
    0
    0
  18. CamoToe1

    CamoToe1 Member

    268
    0
    16
    Recipe for a Lightweight AR:

    16" lightweight midlength upper
    Moe handguard
    A2 FH
    Aluminum lower receiver
    Moe buttstock
    Polymer rear sight
    Any quality BCG

    You can make a lighter AR, but IMO may be sacrificing strength/quality. Lightweight is good, well balanced is great. The AR15 rifle is naturally lightweight so resisting the urge of hanging unnecessary items to it is half the battle.
     
  19. JonM

    JonM Moderator

    20,110
    19
    38

    the only diff tween carbine and middy weight wise is a few short inches of aluminum gas tube. so for a fraction of an ounce you give up a much more gentle recoil impulse which means accuracy/speed loss on follow ups.

    the other thing i dont like about poly recievers is they dont balance well unless you add weight to the stock. a heavier gun that is balanced feels lighter and is faster in swing rate than a lighter gun that is not balanced.

    i find poly reciever ar15 are nose heavy and to me feels clumsy. the blance point on a ar15 should be right at the forward lip of the magwell. this distributes the weight evenly between the pistol grip and handguards.

    anyway mostly just my opinion
     
  20. c3shooter

    c3shooter Administrator Staff Member

    21,511
    804
    113
    I have a Carbon 15. It is not a long range target rifle, but for intermediate distances, not bad. 5.5 lbs unloaded.

    Yeah, I have pistols that come close to that. However, as the weight drops, recoil (even for a 5.56) does start to become noticeable. Have a Browning BAR in .243 that has MUCH less recoil that the carbon 15.