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.
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.
True .
But I read an implication that OP was looking for a .223/ 5.56 . Perhaps the OP can clarify ?
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.
14.5" barrel SBR with BCM pencil barrel and upper. You know you want one.
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.
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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.