Light-weight AR build for the wife

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  • jcutonilli

    Ultimate Member
    Mar 28, 2013
    2,474
    You may want to look at the What Would Stoner Do rifle developed by InrangeTV. It is sub 5 lbs without an optic. It also may not be an "assault weapon" in MD and not require a HBAR barrel.
     

    Biggfoot44

    Ultimate Member
    Aug 2, 2009
    32,877
    Mopar and Outrider hit the key points .

    Mopar linked a Carbon Fibre bbl advertised as HBAR . Short of that , you are inherently constrained by Md legal bbls . As has been mentioned , Fluted isn't automatically lighter than non- fluted , you would need to carefully read the specs .

    As Outrider noted , you don't have much leeway in the basic rifle itself , the biggest thing is to refrain from adding crap onto the basic rifle .

    Reality - Post '13 Maryland , a truely Lightweight AR ( .223 semiauto , traditional operating system ) isn't possible . Instead , your goal is what was originally " standard " weight , ie 7 lb or a bit under .

    As discussed , subjectively the offhand balance can be at least as important to shooter perceptions as the actual total weight .
     

    calicojack

    American Sporting Rifle
    MDS Supporter
    May 29, 2018
    5,348
    Cuba on the Chesapeake
    The biggest trick to building a 'light weight' AR is to not bolt a bunch of tacticool junk on it. You'd be surprised how light a stock AR carbine is.

    YES! Not to mention what ever you do you have to build an HBAR.

    There is another solution; make an SBR with a 14.5" barrel. Then you can use any barrel profile you want. I went that route and have no regrets.
     

    Biggfoot44

    Ultimate Member
    Aug 2, 2009
    32,877
    True .

    But I read an implication that OP was looking for a .223/ 5.56 . Perhaps the OP can clarify ?
     

    Magnumite

    Ultimate Member
    Dec 17, 2007
    6,561
    Harford County, Maryland
    just for the books and comparisons...

    Carbine #1
    Poly/hybrid receiver, 16” 300 BO, w/brake, carbine gas, 12” free float, with MBUS frt/rr, and Bushnell 25 with riser = 6.6 pounds

    Carbine #2
    Aluminum receiver, 16” 5.56 HBAR, carbine gas, w/Phantom 5 fh, fsb with GI handhuards, buis rear, old Tasco 44 mm ProPoint w/riser = 8.1 pounds
     

    River02

    One Ping Only...
    MDS Supporter
    Sep 19, 2015
    3,924
    Mid-Maryland
    True .

    But I read an implication that OP was looking for a .223/ 5.56 . Perhaps the OP can clarify ?

    This is correct-- sorry I didn't make that clear up front.

    Additionally-- the responses to the thread to this point are much appreciated, thanks gents!
     

    calicojack

    American Sporting Rifle
    MDS Supporter
    May 29, 2018
    5,348
    Cuba on the Chesapeake
    14.5" barrel SBR with BCM pencil barrel and upper. You know you want one.

    :party29:
     

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    jjones88

    Active Member
    Apr 4, 2013
    568
    Sykesville
    WWSD rifle, no question. Mine is pre-2013 and is almost under 5 lbs. (5.4 with optic to be exact)

    Easiest way now, would be a 14.5 and go for the SBR. Or replace the Faxon pencil with the carbon fiber barrels mentioned in the earlier posts.

    No need to "skeletonize" anything and the research on all the weights and trades are already done for you.
     

    alucard0822

    For great Justice
    Oct 29, 2007
    17,643
    PA
    You can build a 6# rifle fairly easy, but takes some special stuff and more money to get under 5#. This is a 16", < 5# built I set up for 3 gun. Obviously 5.56 and not Hbar, so not MD legal as is, but in another caliber or as a pistol build with similar principals, and you can probably get to 5# with careful selection of parts. It's substantial compared to a mil spec iron sighted M4 at 6# 9oz unloaded and 7# 13oz loaded. Regardless of the shooter lightweight ARs are fast, fun, and can be very versatile. This one has a big brake, low-mass internals, practically no recoil, and feels like shooting a really loud toy, but still capable of decent accuracy at longer range topped with a LPVO.

    First suggestion is a braced pistol, the barrel profile can add or subtract a ton of weight, Proof Research CF barrels are very nice and Hbar, but not all that light at 27oz for a 16". The Faxon's 16" gunner profine in mine is 22oz, their pencil profile 10.5 is a mere 14.5oz.

    Receivers can save a few oz, but cost can add up quick, and "lightweight/skeletonized" are kinda dirty and not all that light. The V7 enlightened set I used is only 13oz, kinda pricey to save 4 oz compared to mil-specs 17oz(with FA). The 2A balios and V7 are the lightest aluminum sets, polymer can be lighter, but gives up a lot.

    Handguards vary quite a bit, and length matters. The lightest is Brigand CF at an impossible 4.3oz, but you can get Mlok slots and under 10oz(with barrel nut) from a few manufacturers, Midwest Ultralight, V7, and the Odinworks O2 on mine.

    BCG/Buffer are another place where you can save some weight. An M16 BCG weighs 11.6oz, an H2 buffer weighs 4.6oz, and is proven reliable with a wide range of ammo and conditions. Most ALL lightweight BCGs/buffers will need to be tuned with an adjustable gas block. At full gas pressure, they can get damaged or not function, but on the bright side reducing gas and reciprocating mass does reduce recoil substantially, and can be reliable in a narrower window of conditions, although not necessarily "bet your life" reliable. I used an 8.2oz Brownells lightweight BCG and 1.2oz buffer(carbine body with 3 aluminum weights), it is low cost, reliable, light and still has a steel BCG. The lightest is probably a taccom .6oz lightweight buffer setup with a RCA Titanium carrier at 7.8oz.

    Those are the main areas you can cut weight, all together capable of a sleek reliable build that shaves pounds off of a mil-spec M4 or M16 without giving up performance. You might be able to save a couple oz with Titanium parts and a lightweight gas block / muzzle device, but softer titanium pins can wear fast, cost a lot, and aren't a great idea to save fractions of an oz. I do like the Fortis lightweight K1 end plate/castle nut, saves all of .4oz vs mil-spec, but it has a QD socket and the tapered interface keeps it secure without staking, so easy to swap buffer tubes without replacing the end plate. A grip and stock or brace can vary a bit, but they are rearward balanced, so doesn't affect the "feel" all that much. The MFT minimalist on mine weighs 6oz, A SBA3 weighs 7.3oz, lightest of SB's adjustable length(carbine tube mounted) braces.

    20190122_144808.jpg
    20210505_102318.jpg
     
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    ralph.mclean

    GOC (Grumpy Old Cop)
    Jan 27, 2018
    236
    Edgewater, MD
    Folks-

    I like my ARs on the hefty side and I've only built one on my own.

    Mrs. River recently purchased an AR-15 lower and wants to explore options for a light-weight build (NOT X-treme light-weight mind you) but on the less hefty side than mine. So I'm in search of suggestions for what parts and/or complete uppers the brain trust might recommend to make this project a reality.

    I know there are probably slim pickins out there...but we aren't in any rush- so we don't have any issues with punching the "Let me know when it's back in stock" button on the websites for highly recommended parts--thanks in advance!

    Strike Industries sells numerous lightweight parts of respectable quality, AND you can even get them in colors if you want to pretty up her gun a bit.
     

    ralph.mclean

    GOC (Grumpy Old Cop)
    Jan 27, 2018
    236
    Edgewater, MD
    file:///C:/Users/ralph.mclean/Pictures/20200714_191804.jpg

    Build this? This is a 7.62x39 that I built for a friend, on the lower he purchased. About 7 lbs, as is (unloaded mag)...
     

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    ralph.mclean

    GOC (Grumpy Old Cop)
    Jan 27, 2018
    236
    Edgewater, MD
    20200406_190639.jpg

    Or this...?

    Built this one for myself, after having built about 10 "plain" ones for myself and other people....

    Used the blue Strike Industries parts to pep it up a little.

    This one is 7.62x39 also (cheaper ammo = more shooting), and is my absolute favorite. This one is about 6.5 lbs, as seen...

    Both shown have heavy barrels, so I didn't save any weight there.

    I also built an AR-10/.308, with a 20" barrel, but that sucker weighs over 10 lbs. easy
     
    Last edited:

    River02

    One Ping Only...
    MDS Supporter
    Sep 19, 2015
    3,924
    Mid-Maryland
    You can build a 6# rifle fairly easy, but takes some special stuff and more money to get under 5#. This is a 16", < 5# built I set up for 3 gun. Obviously 5.56 and not Hbar, so not MD legal as is, but in another caliber or as a pistol build with similar principals, and you can probably get to 5# with careful selection of parts. It's substantial compared to a mil spec iron sighted M4 at 6# 9oz unloaded and 7# 13oz loaded. Regardless of the shooter lightweight ARs are fast, fun, and can be very versatile. This one has a big brake, low-mass internals, practically no recoil, and feels like shooting a really loud toy, but still capable of decent accuracy at longer range topped with a LPVO.

    First suggestion is a braced pistol, the barrel profile can add or subtract a ton of weight, Proof Research CF barrels are very nice and Hbar, but not all that light at 27oz for a 16". The Faxon's 16" gunner profine in mine is 22oz, their pencil profile 10.5 is a mere 14.5oz.

    Receivers can save a few oz, but cost can add up quick, and "lightweight/skeletonized" are kinda dirty and not all that light. The V7 enlightened set I used is only 13oz, kinda pricey to save 4 oz compared to mil-specs 17oz(with FA). The 2A balios and V7 are the lightest aluminum sets, polymer can be lighter, but gives up a lot.

    Handguards vary quite a bit, and length matters. The lightest is Brigand CF at an impossible 4.3oz, but you can get Mlok slots and under 10oz(with barrel nut) from a few manufacturers, Midwest Ultralight, V7, and the Odinworks O2 on mine.

    BCG/Buffer are another place where you can save some weight. An M16 BCG weighs 11.6oz, an H2 buffer weighs 4.6oz, and is proven reliable with a wide range of ammo and conditions. Most ALL lightweight BCGs/buffers will need to be tuned with an adjustable gas block. At full gas pressure, they can get damaged or not function, but on the bright side reducing gas and reciprocating mass does reduce recoil substantially, and can be reliable in a narrower window of conditions, although not necessarily "bet your life" reliable. I used an 8.2oz Brownells lightweight BCG and 1.2oz buffer(carbine body with 3 aluminum weights), it is low cost, reliable, light and still has a steel BCG. The lightest is probably a taccom .6oz lightweight buffer setup with a RCA Titanium carrier at 7.8oz.

    Those are the main areas you can cut weight, all together capable of a sleek reliable build that shaves pounds off of a mil-spec M4 or M16 without giving up performance. You might be able to save a couple oz with Titanium parts and a lightweight gas block / muzzle device, but softer titanium pins can wear fast, cost a lot, and aren't a great idea to save fractions of an oz. I do like the Fortis lightweight K1 end plate/castle nut, saves all of .4oz vs mil-spec, but it has a QD socket and the tapered interface keeps it secure without staking, so easy to swap buffer tubes without replacing the end plate. A grip and stock or brace can vary a bit, but they are rearward balanced, so doesn't affect the "feel" all that much. The MFT minimalist on mine weighs 6oz, A SBA3 weighs 7.3oz, lightest of SB's adjustable length(carbine tube mounted) braces.

    View attachment 312786
    View attachment 312789

    Incredibly helpful post-- thanks and the pics are certainly welcome and appreciated. As always the MDS folks personal experience and suggestions add value to every project I've taken on to this point-- Great group to be associated with.
     

    lazarus

    Ultimate Member
    Jun 23, 2015
    13,673
    With the HBAR requirement it’s gonna be hard to build a really lightweight rifle . Have you thought about building an AR-15 pistol. You could save lots of weight that way.

    Sort of this.

    To the OP, what is light and what is heavy? How much does your existing "too heavy" AR weigh?

    My 16" AR has plastic flip up BUIS, 12" light weight handguard, fluted HBAR barrel, light weight linear comp and a Sig Romeo 5 on it. I think with sling and no mag it tips the scales at around 6lbs 7oz +/- a couple as I haven't weighed in in awhile and have swapped out some minor parts. I consider it pretty light.

    My 20" AR has a 3-9x40 on it, light weight cantilever base and a regular HBAR barrel, not fluted. 13.5" handguard. Tips the scales with the same lower as the 16" at a hair over 9lbs.

    My 18" 6.5 Grendel AR uses a GWACS monolithic polymer lower, fluted HBAR 6.5 grendel barrel and lightweight 12" aluminum handguard and a 3-9x40 scope with light weight base. It tips the scales at 8lbs 1oz.

    I'd grant my 20" AR is pretty heavy and I built it for bench shooting. I do have a fluted 20 HBAR barrel I plan to try swapping on to it at some point and I'll likely try a lighter muzzle device and gas block. As near as I can tell that'll probably shed about 6-8oz off. Might actually even be slightly more.

    My 16" AR I'd definitely consider light, though not feather weight.

    IMHO I would not go to the extreme, only because of that HBAR, fluted or not. You start getting in to skeletonized receivers and bolt carriers and the balance is going to be all wrong. That 18" Grendel build, the lower is LIGHT. The balance is okay just in front of the mag well (makes it really easy to carry in the field one handed). For shooting it is a bit far forward, but not quite enough to make it unwieldy.

    A 16" would bring the balance a little further back. But you start going nuts on the back end trimming weight and the balance is going to be really far forward.

    Now I guess you could try to track down a fluted HBAR that is 14.5" with a pinned and welded muzzle device that is lightweight in design and a lightweight gas block. That might work fine with a lot of rear end weight loss.

    Anyway, IMHO you don't have to drop a ton of money or work super hard to get an AR with a red dot or mini ACOG that is going to tip the scales under 7lbs, which I'd consider light. If you want to get under 6, you'll have to work at it with a lot more $ and some trade-offs because of the HBAR requirement that is likely to screw with balance.
     

    SkiPatrolDude

    Ultimate Member
    MDS Supporter
    Oct 24, 2017
    3,331
    Timonium-Lutherville
    IMO you really do hit diminishing returns with some of these ultra lightweight builds and at a cost of reliability in many cases.

    A standard HBAR built around a standard receiver set, M16 profile BCG, H buffer and minimalist stock and handguard will be pretty dang light. Or you can spend hundreds more for a difference in weight that you and your wife will likely not feel.

    Fluted barrels are nice, too, but I wouldn't go out of your way to have one fluted or pay too much extra for one. We're talking a few ounces at most.
     

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