In part two of my ongoing series detailing an ultralight AR-15 build, I’m covering the upper receiver. Â The goal of this rifle is to come in under 6 lbs with for the rifle, suppressor and optic. Â Part I in the series dissected the lower, so let’s break down the parts list of the top half.
Sorted by manufacturer:
Bootleg Inc.
- Enhanced Lightweight Upper Receiver.         6.95 oz      $174.95
One of the most oft used uppers for lightweight builds, Bootleg’s slab of 7075 aluminum is light, slick looking and well crafted. Â The scalloped and cut sides give a distinctive look as well as cutting all unnecessary weight without sacrificing strength.
Rubber City Armory
- Titanium Bolt Carrier Group                   7.87 oz     $359
One of the lightest and best reviewed BCG’s out there and with good reason. Â Extremely light and yet yields massive strength by virtue of its nitride treated titanium which increases wear resistance and prevents galling. Â The bolt itself is tool steel, yet with the same coating. Â A lightened BCG provides lower weight as well as lower reciprocating mass. Â While this does necessitate a different balance within the recoil system, it also provides for unbelievable fast and smooth shooting. Â Many shooters think this is only the provenance of competition shooters who never deviate ammo. Â Those competition shooters respond with their own experience showing astronomical round counts, high reliability and nowhere near the ammunition pickiness we’re led to believe by naysayers. Â The standard system is often way overgassed and uses mass to time the system for full-auto fire.
Odin Works
- O2 Lite 9.5″ Kmod Forend                     7.13 oz        $190
- 14.5″ .223 Wyle barrel, Carbine length gas       25.71 oz       $290
- Tunable Gas Block (with gas tube)              2.5 oz         $66
The O2 Lite is… oh too light! Â A strong forend despite its scant weight, the O2 is also available in MLOK flavor. Â Inside diameter of 1.6″ in case you’re interested in “the tuck”. Â The barrel isn’t the lightest on the market, but it isn’t overly heavy and offers a 1 MOA guarantee. Â The tunable gas block adds the necessary function of reducing the gas flow, thus slowing the lightened BCG and preventing it from hulk smashing the inside of the receiver extension. Â It uses two screws in one hole, one to adjust the gas flow and the other to prevent the first from moving once tuned.
Radian Weapons
- Raptor-SD Charging Handle                  1.34 oz        $109.95
Ambidextrous levers provide dual-side charging ability when using the traditional finger-thumb style or when blading. Â The ported design helps reduce gas blow back into the shooters face a bit. Â When combined with the RTV silicon trick, this is the do-it-all charging handle.
Suppressed Armament Systems
- Reaper MX Titanium suppressor             11.68 oz      $1054
- Titanium TOMB mount                     1.98 oz       $199
Having recently written up the TOMB suppressor mount/muzzle brake and Reaper Ti suppressor, so I’ll go over the high notes. Â This can is rated for the .300 magnums yet lighter than many dedicated .223 cans. Â The mount doubles as an effective two-chamber muzzle brake in it’s own right. Â Titanium wins and SAS is knocking out awesome products.
Vortex Optics
- Venom red dot sight, 3 MOA dot             1.6 oz       $229
A micro red dot sight is just as comfortable on a handgun as it is on a shotgun or rifle. This little guy fits the bill for an ultralight rifle quite well. Â The 3 MOA dot isn’t for long-range or precision work, but it sure is fast. Â Battery life is between 150 and 30,000 hours depending on setting.
Heading over to my trusty scale, the upper comes in at 3.351 lbs without optic or suppressor. Â Add on the Vortex Venom and we’re at 3.48 lbs, screw on the SAS suppressor and we’re at 4.184 lbs for the upper. Â Cost for the upper alone (not factoring sales or reduced street prices) is $1388.90, with the $1054 suppressor and $229 optic bringing the total as-built to $2671.90. Â This is a per ounce cost of $39.62. Â Without the suppressor that drops to $28.99/oz. While there are some polymer parts out there that are lighter, I’ve gotta say I don’t trust em. Â I know Glock and the like have been producing polymers that have held up to decades of abuse, but I want to see an AR poly parts manufacturer with a longer track history first.
The lower is at 1.592 lbs after swapping out the standard buffer for Taccom’s Carbine Recoil System (which wasn’t available at the time I had finished the lower).  This bring the total weight of the rifle to 5.776 lbs with suppressor and optic!  I’ll be writing back before long with a range report, covering the tuning of the gas system, how the recoil system works and what kind of accuracy I can wring out of this.  After that maybe I’ll head back to the drawing board to see where I can cut some more weight….
Stay tuned!
