A large-frame rifle specified one part at a time.
$2,700.00 SKU RFL-M5-86BLK-B120-SG
This SOTM5 is a 12″ 8.6 Blackout short-barreled rifle built on Second of Ten’s billet SOTM5 receivers: a thermal-fitted MOD-0 upper over a 7075-T6 aluminum lower. It is gassed to run both supersonic and subsonic 8.6 Blackout, and the barrel, gas system, bolt, recoil parts and controls are each chosen for that job and named below. Receivers and handguard are two-tone: Sniper Grey Cerakote® with a black Cerakote® top Picatinny rail.
SOTM5 names the rifle; the serialized part is the lower receiver. MOD-0 names the billet upper fitted to it, here in its no-forward-assist configuration. RECCE is Second of Ten’s word for the short, light reconnaissance configuration; the stock is Reptilia’s RECC·E™ Carbine Stock, and RECC·E™ is Reptilia’s mark.
The barrel is the part of this rifle that most decides how it shoots, so it is the part chosen first. Second of Ten fits the Faxon Duty Series 12″ 8.6 Blackout barrel in the Gunner profile, and these are the features of it that matter.
A free-float handguard only helps if it stays where it was put. The 9.8″ SOT Wedge-Lock M-LOK® handguard is built around that.
12″ Faxon Duty Series 8.6 Blackout barrel in the Gunner profile: 4150 CMV, QPQ nitrided, 1:3 twist, pistol-length gas. The rest of the rifle is specified around it; the detail is set out above.
The SOTM5 MOD-0 upper is machined from 7075-T6 aluminum billet to the LR-308 DPMS high pattern, with laser-engraved T-marks and a dry film lubed interior. It is thermal fitted to the Faxon barrel, so the joint between barrel and receiver is an interference fit and not a slip fit.
This rifle uses the no-forward-assist configuration of the MOD-0, with the forward assist bore closed by a threaded forward assist pin.
8.6 Blackout is loaded both supersonic and subsonic, and a fixed gas port suits only one of them. The Superlative Arms bleed-off block lets the rifle be set to run both, and to run cleaner suppressed, because excess gas is vented at the block rather than driven into the action.
Faxon Superfinished AR10 BCG, Gen 2, nitride, rated for .308 Win, 6.5 Creedmoor and 8.6 Blackout: MIL-SPEC 8620 carrier, superfinished and QPQ nitrided; 9310 bolt, shot peened and MPI tested; S7 extractor with nested .308 springs and O-ring; 4140 cam pin; heat-treated 4140 gas key on Grade 8 fasteners, fully staked.
The ejection port dust cover is engraved with the caliber on both the interior and the exterior. The marking reads whether the cover is open or closed.
A KynSHOT RB5005 hydraulic buffer with a Tubb Precision flatwire rifle-length spring. Every other buffer moves energy around inside the rifle; a hydraulic damper converts some of it to heat. KYNTEC builds it in 17-4 stainless, rated −30°F to +150°F, for AR-10 and A5-length tubes, and the claim with real weight behind it is reduced bolt bounce.
LaRue Tactical MBT-2S two-stage trigger with a straight bow. It breaks crisply at 4.5 lb (2.5 lb first stage, 2.0 lb second) with a smooth and positive reset. An additional heavy trigger spring that raises the pull to 6 lb is included. Second of Ten does not stone, polish or alter sear engagement surfaces.
Ambidextrous bolt release, with a paddle-style oversized bolt catch on the left and Second of Ten’s own serrated release button on the right. Extended left-side magazine catch release with a right-side button. Breek Arms WARHAMMER Mod2 AR-10 charging handle with oversize latches on both sides.
The Radian Weapons Talon® 45/90 ambidextrous safety selector runs as a standard 90° selector or as a 45° short throw by rotating the shaft 180° inside the lower. It is installed and configured at 90° and can be reconfigured by the end user.
The billet lower carries an upper receiver tension screw, a threaded bolt catch pin and a rear takedown detent spring with set screw, with Battle Arms Development enhanced AR-308 steel pivot and takedown pins.
Reptilia RECC·E™ Carbine Stock for SR-25 / A5 / AR-10, with its own SR-25/A5-length 7075-T6 receiver extension: length of pull 12.375″ to 15″ with a constant cheek weld, switchable QD points, 12.8 oz with the tube. Paired with a Reptilia CQG™-L grip.
This rifle has a zoomable inspection page showing both sides of the rifle as built, so the markings and machining can be read from the photograph instead of taken from a spec table. The serial number is blurred; no other marking is altered.
Open the viewer → SOT_SOTM5-12-86BLK-RECCE_SG_SBR_Zoom_Viewer.html · SOT-WEB-RFL-031Since ATF’s open letter of 9 October 2026, federal NFA registration is not enforced for short-barreled rifles, and this rifle transfers through your FFL on a Form 4473 with a NICS check. State and local law still decide whether you can own one, an ATF Form 20 is still required before taking an SBR across state lines, and the federal policy could change. Confirm with your local FFL before ordering. This is not legal advice.
The adjustable gas block should be set for the ammunition in use, supersonic or subsonic, and reset when a suppressor is fitted or removed. A setting that suits one load is not necessarily right for another.
The Talon® 45/90 selector ships configured as a standard 90° selector. It can be changed to a 45° short throw by rotating the shaft 180° inside the lower receiver.
Photography © Second of Ten LLC. Battle Arms Development, Breek Arms, Faxon Firearms, KYNTEC, Lancer Systems, LaRue Tactical, Magpul, NIC Industries, Q, Radian Weapons, Reptilia, Superlative Arms and Tubb Precision names and marks, including Cerakote®, KynSHOT, MBT-2S, M-LOK®, L7AWM®, MBUS®, PMAG®, GEN M3™, RECC·E™, CQG™, Rocksett® and Talon®, are the property of their respective owners. Their appearance indicates that Second of Ten incorporates the component, not sponsorship, affiliation or endorsement.