If you’re a regular reader of Loadout Room, you may have seen a few articles I’ve posted over the last year detailing the building, then improvement of an off-the-shelf AR-15 that was as light as I could make it while staying within certain constraints.  I wanted a rifle that was under 6 pounds, with the suppressor and an optic attached.  I wasn’t willing to compromise on reliability or strength, staying away from use of polymer receivers and refusing to drill holes or shave parts to achieve weight loss.  I wanted to get a good degree of accuracy out of this rifle, but I went into this knowing maximum accuracy wasn’t likely at such scant weights.  An ultralight AR isn’t sitting in the “best of all worlds” center: it is pushing the weight boundary which necessitates some sacrifices.  Cost?  Reliability?  Durability?  Let’s dig in.

For the rifle alone, version 1.0 came in at 5.05 pounds, while version 2.0 comes in at 4.05 pounds.  That’s only .8 ounces from living in the 3 pound range… something I have an easy path to achieve but won’t write up another update on for less than an ounce.  The suppressor is 11.7 ounces and the Vortex Venom red dot is 1.6 ounces.  That brings this rifle up to 4.88 lbs, suppressed and with an optic.

Ultralight AR-15 ver 2.0 | Final testing
After a couple hundred rounds (suppressed), dirty but still running strong

The parts list for the upper, here.  The only update to this list was the addition of the Sintercore Tripwire SCV (suppressor compatible version) charging handle.  Light, strong and very effective at redirecting gas blowback.

The parts list for the lower, here.  The only update in the lower was to swap out the buffer spring with a Tubb Flatwire spring.

Finally, I got this to the range for accuracy testing.  I popped off the Vortex Venom and topped the rifle with a Trijicon ACOG with the Primary Arms ACSS reticle so I could better gauge the rifles accuracy, rather than my ability to group at 100 yards with a 3 MOA dot.

First, I dialed in a quick zero using Hot Shot 55 gr rounds at 25 yards.  I spent the next hundred rounds getting the Faxon pencil profile barrel nice and toasty, popping clay pigeons at 200 yards.  I figured the ease with which I was hitting the clays at that distance would mean tiny groups at 100 yards, but not quite so.  I switched over to Hornady Match 75gr BTHP ammo and grouped up.  Shooting from a haji squat with the rifle resting on my range bag (on top of a boulder), the results were good but could still be better yet.

Ultralight AR-15 ver 2.0 | Final testing

The best group came in at 1.51 MOA, the worst being 2.38 MOA while not allowing myself to call flyers.  Averaging all of the day’s groups using the Hornady match ammo, 2 MOA was the end result. While that falls short of the internet commando’s requirement that every rifle be sub-MOA, it is far more accurate than the rack-grade M4’s I took to combat.  2 MOA is still sufficient to keep all rounds on a paper plate at 300 yards.  While anecdotal reports online suggest others are having slightly better accuracy results with this Faxon barrel, it wasn’t ever produced with the intention of being the most accurate benchrest barrel.  It is the lightest barrel (per inch of length), at a very good price with very good accuracy.  I’m sure if I shot groups from a more stable rest I could have done a better job on my end as well.

Ultralight AR-15 ver 2.0 | Final testing Ultralight AR-15 ver 2.0 | Final testing

Despite running suppressed and primarily with cheap Russian ammo, reliability with this rifle hasn’t been a problem.  I’ve squirted some of ALG’s Go-juice on the BCG a couple times and the gun just keeps running.  Speaking of the bolt carrier, the 2A Armament titanium, adjustable BCG is awesome.  I have it dialed down to the minimum amount of gas needed to cycle without the suppressor, leaving recoil virtually nonexistent.   It does make me wonder just how much this contributes to the extreme fireball effect (seen below, with and without suppressor)

Ultralight AR-15 ver 2.0 | Final testing
Ultralight AR-15 ver 2.0 | Final testing
and suppressed

And here’s the video showing how little recoil there is in a 4lb rifle with an ultralight BCG and tiny synthetic buffers:


The above photos leave me with an even better impression of how good SAS’s Reaper Ti suppressor is.  It certainly has its work cut out for it on this firebreather, yet is still very quiet.

The Sintercore tripwire charging handle does an excellent job venting gas away from the shooter.  During strings of rapid fire, I was left blissfully bereft of the toxic cloud that usually surrounds suppressed shooters.

Ultralight AR-15 ver 2.0 | Final testing

Ultralight AR-15 version 2.0 |  1 pound lower (part 2)

Read Next: Ultralight AR-15 version 2.0 | 1 pound lower (part 2)

While I barely missed my final goal for the rifle to be sub-4 lbs without suppressor or optic, I’m very happy with how this turned out.  With a new Hogue 15 degree grip and a couple more screws and pins from V Seven, I’ll be easily under the 4-pound mark.  With an incredibly soft-shooting, remarkably light rifle that comes in shooting 2 MOA (or better), I’m happy with how this project ended up.  Overall cost (rifle only): $2367.  Divide that by 64.8 ounces,  $36.50 per ounce.  Rifles like these are expensive but are excellent for pushing the boundaries of what we consider realistically possible in any given weapons platform.  Companies like V Seven and 2A Armament have invested serious time and money into pushing the venerable AR platform further than ever.

A special thanks to those behind the AR15 Parts Weight Database.  I found out about it late in the game, but it did help me with a few products I hadn’t heard of before.  Check it out here.

Rex Nanorum