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 Lightest AR15 build - I need advice.
WSAR15  [Team Member]
4/7/2013 11:29:11 AM EST
I am trying to build and ultra ligfht AR15.

This is what I have scehduled so far:
Barrel: Rock River Chrome Lined 16 Inch Mid-Length Lightweight Barrel Assembly, 1:9 Twist
Lower Reciever: Bane magnesium Alloy lower
Upper Reciever: Std A3 Rock River or equivalent
Stock: ACE ARFX Fullsize Skeleton Stock

I need your help for a light weight handguard tube (free float with or without rails) - I welcome your suggestions.
Thanks for your help
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thebuckeye  [Team Member]
4/7/2013 11:51:58 AM EST
The Noveske NSR will be hard to beat for weight and you can choose from a few sizes. The Fortis Rev is very light, but you only have the 12" to choose from.
AR-4C  [Member]
4/7/2013 11:55:40 AM EST
I got a 12.5" Odin Works KMod, and it's super light and strong.
PursuitSS  [Team Member]
4/7/2013 11:59:40 AM EST
Originally Posted By WSAR15:
I am trying to build and ultra ligfht AR15.

This is what I have scehduled so far:
Barrel: Rock River Chrome Lined 16 Inch Mid-Length Lightweight Barrel Assembly, 1:9 Twist
Lower Reciever: Bane magnesium Alloy lower
Upper Reciever: Std A3 Rock River or equivalent
Stock: ACE ARFX Fullsize Skeleton Stock

I need your help for a light weight handguard tube (free float with or without rails) - I welcome your suggestions.
Thanks for your help


I would go with a lightweight 14.5" barrel with a permanently attached muzzle device
Also use the Rock River 9mm upper receiver drilled for the gas tube.
five821  [Team Member]
4/7/2013 12:00:24 PM EST
Originally Posted By WSAR15:
I am trying to build and ultra ligfht AR15.

This is what I have scehduled so far:
Barrel: Rock River Chrome Lined 16 Inch Mid-Length Lightweight Barrel Assembly, 1:9 Twist
Lower Reciever: Bane magnesium Alloy lower
Upper Reciever: Std A3 Rock River or equivalent
Stock: ACE ARFX Fullsize Skeleton Stock

I need your help for a light weight handguard tube (free float with or without rails) - I welcome your suggestions.
Thanks for your help


link 1

maybe this one

I like my magpul MOE
weptek911  [Team Member]
4/7/2013 12:07:21 PM EST
I have a Cav Arms synthetic all in one lower with a flat top receiver and a lightweight colt 16" barrel, comes in at 5.5 pounds with a BUIS on the rail.

/Just thought I'd share.
ACOGMan  [Member]
4/7/2013 12:12:19 PM EST
Originally Posted By weptek911:
I have a Cav Arms synthetic all in one lower with a flat top receiver and a lightweight colt 16" barrel, comes in at 5.5 pounds with a BUIS on the rail.

/Just thought I'd share.


The Cav Arms lower is unbeatable for the weight reduction. However, as many people will probably tell you, its more about balance then weight. You dont notice a heavy stock (its on your shoulder), but you will notice anything forward of the upper receiver. If you are hell bent on free floating it, a good value is one of the YHM free float tubes, or a Troy TRX Extreme free float rail system. If you dont need free float, standard mid length carbine handguards are about as light as it gets.

14.5" Lightweight barrel w/ perm attached muzzle device and a really light rail will get you what you are looking for.
Plumber576  [Team Member]
4/7/2013 2:16:36 PM EST
13.5" NSR here, and it is super light. My flash hider is more noticable than the handguard when it comes to added weight.
GoRebels  [Team Member]
4/7/2013 3:48:36 PM EST
I vote NSR but if looking for something a little more available then Fortis has a badass light rail.........
LMTRocks  [Team Member]
4/7/2013 6:40:43 PM EST
I'm using the Odin 9.5 on my 16" 5.45x39 build.

I decided to pull the port cover and f/a off the upper as they will be milled down eventually. I'm also considering skeletonizing the lower on the right side of the magwell for further weight reduction.

I was originally going to use the Noveske NSR9, but when we got the Odin Works 9.5 KMod rails I decided the $100 savings would be worthwhile to me.

I do like the Noveske, though, and I'm still on the fence about getting that instead.

For a LW barrel, you'll want to stick to a .625 gas journal and consider a .600 contour forward of it.

I'm going to have my 5.45 barrel contoured down to a .625 gas journal from .750 and then the M4 cut area to .600 also. I will be using my YHM Ti762 on a 5.56 QD so I don't want the barrel to be too skinny. Suppressor and mount weigh between 18 and 19oz.

Finally the optics will be a Vortex SPARC and Magpul MBUS.

The only heavy part of the gun is the B5 SOPMOD in FDE which matches the Noveske NSR FDE panels nearly perfectly. I might have to try to procure a Magpul FDE RVG but I think the black RVG will look best.

Good luck OP.
WSAR15  [Team Member]
4/8/2013 2:27:05 AM EST
Thank you very much.
Would a 12" handguard be OK on the mid-length gas port 16" barrel?
Also - one gentleman advised a 9mm upper drilled for the tune - why the 9mm upper - is it lighter than a std 223 upper?
Moondog  [Team Member]
4/8/2013 3:07:29 AM EST
Originally Posted By WSAR15:
Thank you very much.
Would a 12" handguard be OK on the mid-length gas port 16" barrel?
Also - one gentleman advised a 9mm upper drilled for the tune - why the 9mm upper - is it lighter than a std 223 upper?


A 12" handguard should be fine.
Regarding a 9mm upper, the samples I've seen did not have a forward assist, so you'll shave some weight by having less parts.
WSAR15  [Team Member]
4/8/2013 3:33:00 AM EST
Good point Moondog - Thanks
Norinco982lover  [Team Member]
4/8/2013 4:02:03 AM EST
You will need a low profile gas block or a cut down FSB if using a longer rail (just making sure you know).

I have the 13.5 NSR and its super light but hard to find.

Try the fortis, Samson evolution, or one of the Troy/vtac alpha style rails.

ziarifleman  [Team Member]
4/8/2013 4:27:22 AM EST
Carbon fiber handguards are so light it's ridiculous.
matt2k12  [Member]
4/8/2013 6:05:24 AM EST
If its really a lightweight build why not go poly lower and upper? Especially if only shooting 5.56 or lower caliber ammo. I too am intrigued by a lightweight build and have the NFA lower laying around. Problem is it already broke in one spot so I'm sending it in for warranty. I wouldnt shy away from polymer parts if you are wanting a true lightweight build. You get what you pay for and as easy as these things are to work on I dont think poly parts deserve the shunning they receive. Just know what to expect when buying. The mag alloy parts are great but I wouldnt use them on an upper for obvious reasons. I have a few mag alloy lowers I like but they seem excessively soft.

My first build was a NFA lower with an h bar barrel. I kinda liked the lightweight build with a heavier barrel because I really feel like all I have to do is look down the scope and point that barrel in the right direction. The rest of the gun sorta disappears, almost like youre just holding a barrel and a scope. I'm not into all the gadgets and gizmos if they arent really functional. I like a sleek build with ACOG optics. I like a gun I can use for defense and also take out and stalk/hunt without worrying about weight or getting snagged on branches, etc.

Would love to see some pics of everyone's lightweight builds.
Moondog  [Team Member]
4/8/2013 6:34:50 AM EST
The OP already is looking at a magnesium alloy lower, and if he chose to go poly, I'd only recommend the Cav15 lower because it's light weight and proven design.
protondecay123  [Team Member]
4/8/2013 7:25:07 AM EST
Midwest Industries SS free floats are feather light. Also PSA has a chrome lined pencil prfe barrel that is very light. Would look at a Youngs National Match light BCG or JP Low Mass.
WSAR15  [Team Member]
4/8/2013 7:39:16 AM EST
I want to free float the 16” barrel (not shorter) and it’s a 223 only. Someday I’d also like a SBR, but for now I’ll stick to this project and start buying parts as they become available and if normally priced (Good bolt carrier and bolt are hard to find).

I was looking at the clamp style low profile gas block from Yankee Hill, Sadlak (if in .625), Daniel defense or Vltor.
Any other recommendations or preferences?

The Carbon Lancer Rifle 12.5” is certainly intriguing @ 11-13.3 Oz. with a short rail at the end for a sight, but its $227.99 (Midway). I need to look more into it.
The Noveske NSR is very nice and the 13.5” should work (maybe the 11” but I don’t know yet where the mid gas port is exactly located. It seems very flexible and quite narrow. The panels are also nice.

I am not keen on Poly lowers but I admit I have no particular reason beyond a gut response to key parts in plastic (Also, I thought CAV was out of business). Years ago I heard rumors that Colt was looking into nonmetal lowers.

Again, I appreciate all your help and suggestions.
Thank you.
Rugger_ag  [Team Member]
4/8/2013 8:24:07 AM EST
cav arms lower a2 upper pencil barrel and plastic psa handguards. mine feels lighter than a bb gun
Rugger_ag  [Team Member]
4/8/2013 8:35:54 AM EST
the cav lowers are being made by someone else. the plastic on them is the same type you find on a solid plastic buttstock, they do not feel flimsy at all
Combat_Jack  [Team Member]
4/8/2013 9:06:04 AM EST
Rainier has uppers without FA, saves 1.7 ounces.

WSAR15  [Team Member]
4/8/2013 10:20:34 AM EST
This is what I found on the www.gwacsarmory.com site which now manufacturers le Cav Lovers:
Nylon 6/6 is a superior performer. Of all the unmodified nylons, it has the highest melting point, is the strongest, and the most rigid. Nylon 6/6 is an excellent replacement for a wide range of different materials ranging from metals to rubber because of its toughness, and combination of low coefficient of friction and good abrasion resistance. This product has outstanding resistance to acids, alkalis and organic materials, as well as good electrical insulating characteristics and noise damping properties.
Standard metal working equipment is suitable in the fabrication of precision parts. The combination of machinability, excellent properties, and performance have made Nylon 6/6 the most widely used nylon in American industry.
This is not a Polycarbonate
Combat_Jack  [Team Member]
4/8/2013 10:26:06 AM EST
I had an upper without the FA and a Cav lower put together at one time. Almost too light.
mrs50sls56  [Member]
4/8/2013 1:05:21 PM EST
This is a simple solution; not super light, but not super expensive either. GWACS lower, 16" LW Mid BCM. MBUS. MOE.

matt2k12  [Member]
4/8/2013 1:58:26 PM EST
Looking good. And I would even go with a 14" and muzzle device for more weight savings. I am just imagining that thing on a sling while hunting deer or other game and creeping thru the brush. My current hunting rifle is a heavy beast.
WSAR15  [Team Member]
5/18/2013 2:10:19 PM EST
AP Customs has a nice looking lightweight Carbon Hanguard at a good price (<$200).
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