Description
The same 18″ SOLGW Precision SPR barrel, with the RIFLESPEED Gas Control fitted in place of the fixed block — same .750″ journal, same alignment check, same stainless coiled pin, twelve numbered settings instead of one.
Fixed gas ports are sized for the worst case, which means nearly every AR leaves the factory overgassed by design. An adjustable block takes that back — but the real value is repeatability. Twelve numbered positions with a tactile click, adjusted by hand without tools and without pulling the handguard, give you a setting you can record beside the load and the conditions and return to a year later. This is a cycling and impulse feature, not an accuracy feature, and it cannot add gas beyond what the barrel port gives it.
Fitted and tuned with the #887 plunger — the size RIFLESPEED recommends for the six-millimeter cartridges. A shorter plunger meters more gas at every position, so the working setting sits low on the dial with reserve held above it. RIFLESPEED’s standard #917 plunger is also included in the box, so the gas system can be configured further by the shooter: fit the #917 and the whole range moves up the dial. The plunger and setting are recorded on the barrel inspection record.
An adjustable block is the one component you deliberately reach out and turn, so it gets both retention methods: set screws torqued to specification and a stainless steel coiled pin through the control body and the barrel. A recorded gas setting is worthless if the block can creep underneath the numbers.
Converted to the LMT® MRP™ barrel interface, then inspected, gauged and assembled by the Second of Ten build team to a documented standard. Installs with the MRP™ upper’s factory barrel hardware — no proprietary tooling and no permanent modification to the receiver. Headspace is gauged and recorded on the barrel inspection record before shipment.
Ships shooter ready: gas tube installed and the muzzle protected by the SOT Standard Barrel Thread Protector (CNC-machined steel, black or nitride finish), with no muzzle device fitted. Brakes, flash hiders and suppressor mounts are fitted and timed to order through the SOT Custom Shop. A headspaced bolt carrier group can be added and gauged to this barrel: SOT Enhanced Microbest C158 MPI DLC+, SOT Enhanced HM Defense in Black Nitride, or the SOT Enhanced Microbest Super-Stake with the Young Manufacturing HMB™ bolt.
At 18 inches this barrel builds a conventional rifle — no tax stamp, no registration and no wait. Requires 6mm Max® magazines.
Includes
- 18″ SOLGW Precision SPR barrel, converted to the LMT® MRP™ interface
- RIFLESPEED Gas Control, installed, aligned, torqued and pinned with a stainless steel coiled spring pin
- #887 plunger installed and tuned, optimized for 6mm Max®
- #917 plunger, loose in the box
- RIFLESPEED straight rifle-length gas tube, installed
- SOT Standard Barrel Thread Protector, fitted (CNC-machined steel, nitride finish)
- Vacuum-sealed, with a Zerust® corrosion-inhibitor tube in the bore (remove before firing)
- Barrel inspection record (SOT-BIR-001)
Options
- Headspaced bolt group: SOT Enhanced Microbest C158 MPI DLC+
- Headspaced bolt group: SOT Enhanced HM Defense, Black Nitride
- Headspaced bolt group: SOT Enhanced Microbest Super-Stake with Young Manufacturing HMB™
- Muzzle devices from other manufacturers, installed and timed — for a specific muzzle device, please ask before ordering
Matching headspaced bolt
Choose a bolt above and we gauge headspace with it in this barrel and record the pairing on the barrel inspection record, so the two ship as a matched set.
Full specifications, photos and the inspection standard
Shipping: we do not ship barrel assemblies to CA, CT, DE, DC, HI, IL, MD, MA, NJ, NY, RI or WA, or to Denver, CO or Cook County/Chicago, IL. Questions? Ask your local FFL.
WARNING: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.
