8.6 Blackout Pistol

::  First and only 8.6 build on a VAF DaVinci receiver set
::  Compact, sub-10” AR-10 platform
::  Custom multicam finish by Koted Arms

For quite a few years, 300 Blackout has been a popular choice for many shooters. Strong .30-caliber ballistics from a short barrel, compatibility with suppressed shooting, and mild recoil make it a favorite for many. The ability to swap between supersonic and subsonic loads further cemented its reputation as one of the most versatile AR-15 calibers.

I’ve built more than a few 300 BLK rifles and pistols, and the round continues to impress. Still, when Q announced they were working on an evolution of the concept in the form of the 8.6 Blackout, the idea of going bigger was too good to ignore. The design philosophy was the same: a short-barreled platform optimized for suppressed fire, only this time built on the AR-10 footprint with far more knockdown power.

That combination of compactness, suppression, and large-caliber energy made the 8.6 a natural step forward for a builder looking to try something new. This pistol became my chance to explore the caliber in detail and see what it could do in a lightweight, packable format.

One-Off Receivers

This firearm is unique in more ways than one. It’s the only 8.6 Blackout build to ever feature the Violent Art Firearms DaVinci billet receiver set. The DaVinci line was meant to expand into multiple sizes, but production ended when the manufacturer supplying them shut down. That left this build as the sole example in 8.6 under that banner.

The DaVinci lower is machined from 7075 billet aluminum and features clean lines, an ambidextrous bolt catch, and a strong but lightweight profile. The upper shares the same billet styling, and together they create a platform that’s visually distinct while being just as rugged as any other AR-10 receiver set. That exclusivity alone makes this project stand apart.

Deep Dive on the Upper

One of the most critical parts of an 8.6 build is the barrel. Q experimented extensively with different lengths and twist rates to find the best formula. The result was clear: heavy bullets, short barrels, and fast twist rates were the way forward.

For this build I turned to Mos-Tek, a local custom barrel manufacturer with a reputation for excellent work. They can produce nearly any caliber, cut custom profiles, and even fit barrels flush to a handguard if you provide the rail. The barrel here is a 9-inch 416R stainless unit with their Whisky profile, cut with an extremely fast 1:3 twist. That rapid twist is essential for stabilizing the heavy 280-grain subsonic bullets this caliber was designed for.

The gas block journal is .875 and paired with a Superlative Arms adjustable gas block. With so many unknowns in tuning an AR-10 pistol, being able to fine-tune gas flow is critical. Unlike the AR-15, the AR-10 lacks a universal spec, so each build requires dialing in. The adjustable block made that possible.

The handguard is another area where AR-10 builds can present challenges. At the time, most AR-10 rails were 15 inches or longer—fine for rifles, but unsuitable for a short pistol. Fortunately, SLR Rifleworks offered solutions. Their Helix series comes in both DPMS high and low profiles, and in a wide range of lengths. The 8-inch Helix used here fits perfectly with the 9-inch Mos-Tek barrel, leaving just enough room for the suppressor.

Up front, a JMAC Customs HRD finger stop in “Gucci Green” adds a bit of forward control. It’s light, unobtrusive, and easy to use when needed. The green also ties into other accents on the build.

Muzzle Device & Suppressor

Rearden Manufacturing was one of the first to release 8.6-specific muzzle devices. Their R2S brake is designed with the same internal shoulder angle spec that Q established, which ensures proper sealing and secure lockup. It’s a small but important detail for reliability.

As with 300 BLK, shooting 8.6 Blackout suppressed is practically mandatory. The concussion from an unsuppressed short-barreled .338 would be punishing at best and range-clearing at worst. For this build, the suppressor of choice is SilencerCo’s Omega 36M.

The 36M is modular, so you can run it in either a shorter or longer configuration. At full length, it measures 6.85 inches and weighs just 12.5 ounces. The weight savings come from a mix of titanium, 17-4 stainless steel, Inconel, and Cobalt 6. It’s one of the most versatile suppressors available and an ideal match for the 8.6 platform.

Inside the receiver, the bolt carrier group is another rare component. It’s an Iron City Rifle Works Black Diamond-coated BCG, one of only a handful produced before the company closed. 

The slick coating and black chrome appearance make it a standout piece, and its performance matches its looks.

The charging handle is Aero Precision’s Breach ambidextrous large-handle model in OD green. The oversized latches are glove-friendly, a practical choice for a pistol that might be used outdoors in all conditions.

For white light, the pistol runs an HRT AWLS 18350. It outputs a neutral 5,500K beam at 90,000 candela, plenty for positive target identification. Its joystick switch can be pressed from any angle for momentary activation or fully depressed for constant-on, making it intuitive to use under stress.

Given the unknown recoil characteristics of early 8.6 builds, a durable optic was required. The EOTech XPS2 in green was selected, offering both rugged construction and a color match to the build’s accents. The holographic sight’s proven reliability made it the safe choice.

Dialing In the Lower

The lower receiver houses a Timney Daniel Horner two-stage trigger. With a flat, thin shoe, it feels precise whether you are shooting barehanded or with gloves. The first stage is a feather-light half pound, while the second stage can be adjusted between one and 2.5 pounds. The combination makes it fast and responsive, making it feel equally at home in competition or defensive use.

Forward Controls Design supplied the ambi safety selector and mag release. The selector uses a 50-degree throw and provides a tactile, positive feel. The mag release’s serrated billet face, also from FCD, makes it easy to actuate under stress.

The magazines used here are standard Magpul Gen 3 20-round PMAGs. Recoil management is handled by a Kynshot hydraulic buffer paired with a Battle Arms Development carbine buffer tube and spring. This particular Kynshot unit weighs 3.8 ounces and does an excellent job reducing felt recoil.

The Finish

Another defining feature of this build is the finish. I’ve always had a thing for camouflage patterns, but surprisingly, we hadn’t done many projects in standard multicam. This seemed like the perfect platform for it. Instead of the more common brown-based version, we went with black accents for a subdued, modern look.

Koted Arms in Tempe, Arizona, laid down the coating. They’ve handled countless projects for me, from simple jobs to complex patterns, and their work is always flawless. The finish ties together every component and contrasts nicely with details like the Phase 5 strap on the SB Tactical SBA4 brace.

Despite the larger AR-10 frame, the pistol weighs just 8 pounds, 6 ounces fully built. With the suppressor attached, overall length measures 35.25 inches. For a system chambered in .338-diameter bullets, that’s an impressively compact package that can be easily slung over a shoulder or carried in a backpack.

On the Market Now

When this pistol was built, 8.6 Blackout was still new and unproven. Today, the platform has finally matured. Ammunition is available from several manufacturers, and barrels, gas blocks, and rails are easier to source. While it’s still more expensive than mainstream calibers, it’s no longer an experiment.

Subsonic hunting and defensive loads, such as the 280-grain rounds from Discreet Ballistics, make the caliber especially effective for suppressed applications. As with any niche caliber, cost remains a barrier, but with more adoption, prices for this incredible cartridge may eventually come down.

Final Thoughts

This 8.6 pistol represents a unique intersection of timing, design, and parts availability. It’s the only 8.6 build on the DaVinci receivers, with a standout finish and carefully chosen components that balance rarity, performance, and style.

The result is a compact AR-10 pistol that weighs less than nine pounds, runs smoothly, and offers one of the most potent short-barrel suppressed setups available today. Whether you see it as a collectible one-off or a capable backcountry defensive tool, it proves what 8.6 Blackout can do when applied to a purpose-built platform.

Would you choose a longer barrel for more velocity, or keep it short for the ultimate power-to-weight ratio? That’s the question the 8.6 Blackout invites every builder to answer for themselves.

Build Sheet

8.6 Blackout Pistol

Specifications
Caliber: 8.6 Blackout
Capacity: 20+1 (as shown)
Overall Length: 35.25 in. (w/ suppressor)
Weight: 8 lbs, 6 oz.
Barrel Length: 9 in.

Featured Accessories
Optic: EOTech XPS2 Green
Suppressor: SilencerCo Omega 36M
Barrel: Mos-Tek 9 in. 416R, Whisky profile, 1:3 twist
Handguard: SLR Rifleworks Helix 8 in.
Receivers: Violent Art Firearms DaVinci billet set

Parts & Accessories: Iron City Rifleworks Black Diamond BCG, Aero Precision Breach ambi charging handle, JMAC Customs HRD finger stop, Rearden R2S muzzle device, Superlative Arms adjustable gas block, Timney Daniel Horner 2-stage trigger, Battle Arms Development buffer tube/takedown pins, Kynshot hydraulic buffer, Magpul PMAG 20-round, Forward Controls ambi safety & mag release, SBA4 brace with Phase 5 strap, Iron City Rifleworks billet grip, HRT AWLS 18350 weaponlight