View Full Version : Lightest AR-15?

05-08-2011, 5:57 AM
What is the lightest AR you built? What parts did you use other than a polymer lower? I am looking to build an uber-lightweight upper for fun plinking and looking for ideas. Thanks.

05-08-2011, 7:12 AM
I built a plum crazy lower with PWS piston upper aimpoint H1 with mount , magpul BUS and surefire G2 it came in at 7.8 LBS with full mag.

05-08-2011, 7:32 AM
5.56geo's AR is about 5 lbs or less and he has a Magpul rifle (handguards, pistol, foregrip,and stock). That thing is super light.

05-08-2011, 7:37 AM
if you dont want the polymer stuff troy trx rails are some of the lightest. i have the troy trx extreme 13" and it weighs 13 ounces i beleive the shorter ones are even lighter of course. unfortunatly my eotech is pretty damn heavy with full mag i'm at 8.5 lbs

05-08-2011, 7:55 AM
My AR is at 6.8lbs with a full mag:

Spikes Lower
CMMG upper
Magpul stock
Pencil Barrel

05-08-2011, 8:01 AM
DD A1.5
BCM mid length lightweight upper with basic plastic handguards

Very light and maneuverable :D

05-08-2011, 8:03 AM
lightweight pencil barrel is going to make about the largest difference.
Magpul MOE stuff is strong and light. Don't put on anything you don't need.
a little race car builder's wisdom; "The best way to shave off a pound, is to find 16 places to shave an ounce."
i'm curious what a DPMS varmint upper receiver weighs compared to a standard one (no FA, no dust cover, no shell deflector)

05-08-2011, 8:04 AM

Double Star 14.5" 1x9 chrome lined barrel w/ Phantom flash hider and PRI flip up front sight, AFM lower with Armalite parts kit, Magpul MOE handguards and pistol grip, CTR butt stock, enhanced trigger guard, ASAP sling plate with MS2 sling, and BAD lever; Aimpoint H1 Micro, ARMS #40L BUIS - Haven't weighed it out, but it's very light.

05-08-2011, 8:15 AM
just plan it carefully and weigh everything out. Many people think MOE handguards are the way to go but if you weigh everything out a lightweight rail will save you weight.

When I built my lightweight upper I weighed every single peice on it and found out that my Larue gooseneck rail with lo-pro gas block weighed very close to the standard a2 FSB, midlength MOE and delta ring. so just plan it out and you will happy

05-08-2011, 8:21 AM
No plastic...
IIRC Sun Devil Lowers are 6061-T651 Billet and weight less than a normal lower. fraction of a ounce, but everyone counts. weight one to be sure.

11.5" pencil barrel with a 5.75" 6061-T6 muzzle device, (xm-177 moderator). This should weigh less than a 16" 4140/4150CMV barrel.

low mass hammer and skeletonized trigger.

I do not know of a lightweight upper...all the billets I know are beefed up so the weight will be the same or more. No FA or deflector or door will save weight, so a slab side upper.

UTG 6061-T6 Mil-spec extension tube...made in USA...mil-spec sized, crappy cheap anodizing, acceptable metal...light weight.

Cheap tapco/CAA/UTG M4 stock...cheap plastic, shorter than normal M4 Stocks and must weigh less.

C- type BCG, I think they weigh less than the low mass ones LMT has. (I think LMT sells them...maybe JD???) In any case the C-type will be hard to find . You could have a machine shop cut a semi-auto into a C-type for you.

A2 cast FSB no bayonet lug...every ounce helps.

I bet this would be extremely light.

05-08-2011, 8:32 AM
Probably a Bushmaster Carbon-15 is about the lightest complete ar-15 style rifle you can get.

A Bushmaster Superlight Carbine is weighing in at 6.25lbs according to bushmaster and thats with a carry handle for a rear sight and a mil-spec buttstock. You could probably shave off another half pound or more by going with an LMT rear sight and an ACE ARUL stock like this:


You'd probably be in the 5.25 or so lb range and a crazy light rifle at that.

05-08-2011, 9:44 AM
didn't we just do this?


05-08-2011, 9:48 AM
CMMG lower
CMMG 20" LIGHTWEIGHT profile rifle upper
A2 plastic stock.

Airsoft light:)

05-08-2011, 9:52 AM
i can't resist.