The O.G. – Tom Marshall’s Do-All Survival SBR

The O.G. – Tom Marshall’s Do-All Survival SBR

It’s been said before that “the most dangerous weapon in the world is a Marine and his rifle.” While I wasn’t a Marine, I’d like to think that a capable rifleman and his rifle are a force to be reckoned with, Marine or otherwise. As such, a well-tuned and highly capable carbine is an absolute staple of prepared living. There are many like it, but this survival SBR is mine.

This article originally appeared in Issue 60 of Recoil magazine.

The Survival SBR Build

I started with the military’s “recce rifle” concept (essentially an accurized AR), scaled down to leverage current advancements in barrel technology. This build sports a tube from Rosco Manufacturing. Specifically, this one is their collaboration barrel, built with input from Aaron Cowan of Sage Dynamics. It’s a 12.5-inch barrel made from 416R stainless with a 1:7 twist and NATO-spec 5.56mm chamber. The barrel is finished in black nitride and features a proprietary “patrol length” gas system that is somewhere between carbine and mid-length. The idea behind this was to create a system more reliable in the short barrel than true mid-length, but without the over-gassing that occurs in carbine-length SBRs — particularly when running suppressed.

This barrel is mated to a lightweight Balios Lite upper from 2A Armament, which is slicked down and lightly skeletonized to reduce weight. The lower is an ADM UIC lower, built for hard-use and sporting a full suite of completely ambi controls. The back end is built around a Primary Weapons Systems enhanced buffer tube and ratcheting castle nut with B5 SOPMOD Bravo stock. The recoil system is a Sprinco “blue” spring with Spikes ST-T1 buffer. A Rise Armament RA-535 trigger, with 3.5-pound single-stage break and a blazing-fast reset, allows for both long-range precision and rapid-fire when needed close-in.

The handguard is an SLR Rifleworks ION Ultra Lite 11.7-inch tube. The ION Ultra Lite features seven sides of M-LOK slots as well as several more M-LOK cutouts along the 12-o-clock axis, with a small section of Picatinny rail at the muzzle end. I tried to make best use of this configuration by clamping a Holosun LS-321 IR laser/illuminator to the front rail section, which is controlled by a Unity Tactical TAPS switch attached directly to the 12-o-clock MLOK slots. The TAPS is a dual-lead switch that single-handedly operates both the laser and white light – in this case, an Arisaka 18650 light body with SureFire UE-series tailcap and Malkoff Devices E2XTL head. This head produces 500 lumens and 55,000 lux. The beam pattern is tight and well-directed with minimal spill, making it especially useful at extended ranges while still providing a large bright spot in CQB. The light is mounted via an Arson Machine inline MLOK mount that pushes the light out almost to the end of the suppressor to minimize barrel shadow. The 12-o-clock position of the TAPS, combined with fully ambi controls including Radian safety and charging handle means the manual-of-arms is perfectly mirrored regardless of which shoulder you’re shooting from.

Speaking of line-of-sight, the optics system consists of a Vortex Razor Gen III 1-10x, mounted in an ultralight Scalarworks mount, paired with a Trijicon RMR on an Arisaka offset mount, which can be configured to either 35- or 45-degree offset to accommodate scope clearance and shooter preference. It should be noted that the Razor is mounted in a 1.57-inch height mount for better cheek weld during prone or long-range shooting, while the RMR is in a 1.93-inch mount for faster acquisition in heads-up shooting, and to permit passive aiming through NVGs.

Furniture is rounded out with a B5 systems Type 23 pistol grip and Strike Industries short angled vertical grip. The Type 23 offers a more vertical grip angle and comes with stippling on both sides and the front strap. We had P4 Coatings add matching stippling to the backstrap for better grip during one-handed manipulations, particularly when running the gun muzzle-up. The Strike short angled vertical grip offers just-enough vertical grip to drive the gun and provide consistent support-hand indexing without excessive protrusion. This grip also has molded-in channels for cable management, but we found Strike’s Siegen MLOK inserts to be better suited for our setup. Support-hand grip surface is augmented with insert panels from Walker Defense Research. These polymer panels are dusted with silicon carbide grit to provide a no-fail grip surface while still being lightweight and low profile.

The build is topped off with a Blue Force Gear VCAS sling stowed with a Neomag Sentry Strap. The Sentry Strap wraps around the handguard and is held in place with Velcro, while a small tail with sewn-in rare earth magnets keeps the wrapped up while not in use. To deploy the sling, simply tug on it to break the seal between the magnets and you’re ready to go. The barrel is capped with a Rex Silentium MOD X suppressor. The MOD X is a two-part can unique in that, when you order from a Rex dealer, it can be custom-configured to any combination of baffles for both base unit and extension. The base unit can be as short as 3 baffle, and the total baffle count can go as high as 14. We chose to set ours up with a 3-baffle base unit (seen here) with a 5-baffle extension. The base unit is a compact 4.1 inches long and weighs only 8 ounces. The stubby base unit, when used alone, is far from Hollywood quiet but provides enough sound suppression to save your hearing while still being short enough to carry the complete rifle in most SBR backpacks. For more deliberate shooting sessions like classes and range days, the additional 5-baffle unit can be threaded on for better sound suppression.

The sum total of these parts is a single survival SBR that’s capable of both CQB and long-range precision (we’ve run this rifle past 800 yards with repeatable hits on steel), day and night capable using white light or night vision that can still be packed away in a duffle bag, backpack or between the seats of an SUV. It’s truly a go-anywhere, do-anything rifle we expect would serve us well in any emergency.

Selected Parts List

ADM UIC-15 Lower ($350)
www.admmfg.com

Primary Weapons Systems Enhanced Buffer Tube Kit ($110)
www.primaryweapons.com

Rise Armament RA-535 trigger ($260)
www.risearmament.com

B5 Systems SOPMOD Bravo ($60)
www.b5systems.com

Rosco 12.5” Sage Dynamics K9 Barrel ($170)
www.roscomfg.com

Vortex Razor Gen III 1-10x ($3,600)
www.vortexoptics.com

Scalarworks LEAP ($399)
www.scalarworks.com

Unity Tactical TAPS ($175)
www.unitytactical.com

Arson Machine Inline Scout Mount ($48)
www.arsonmachine.com

Arisaka 18650 w/Malkoff Devices E2XTL Head ($266)
www.arisakadefense.com

Holosun LS321G ($970)
www.holosun.com

Strike Industries Short Angled Vertical Grip ($22)
www.strikeindustries.com

Strike Industries Siegen Rail Panels ($15)
www.strikeindustries.com

Walker Defense Research NILE MLOK panels ($50)
www.walkerdr.com

Rex Silentium MOD X ($1,100)
www.rexsilentium.com

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