Sig Sauer Mcx Pmcx300B9Bir Spearlt Ir 300Blk 30R Fde

The SIG Sauer MCX-SPEAR LT IR is a compact 300 Blackout semi-auto rifle built for shooters who demand thermal signature reduction without sacrificing practical performance. Wrapped in Cerakote Gen II IR Coating—the same infrared-suppressing finish that protects against wear and corrosion in harsh conditions—this 9-inch barreled platform brings SIG's proven MCX reliability into a package trusted by special operations units worldwide. Whether you're running suppressed subsonic loads, testing equipment at the range, or building a dedicated short-range rifle, the MCX-SPEAR LT IR delivers the ergonomics and controls you expect from a modern tactical semi-auto, paired with the thermal management features that set the IR Series apart.

The firearm centers on a cold hammer-forged, 300 Blackout barrel with a 1:5 twist and 5/8"-24 threads ready for suppressor mounting via the included QD flash hider. An adjustable gas piston system lets you tune reliability and recoil to your ammunition and setup, while the SIG Flat Blade Match trigger provides a predictable, shootable break. Fully ambidextrous controls mean lefties and righties operate the same controls without compromise. The lightweight alloy handguard rides M-LOK slots for mounting lights, lasers, or optic mounts, and the PCB-type tele-fold stock collapses the overall length from 27.5 inches to just 16.38 inches—critical for vehicle stowage, CQB work, or compact carry in tight spaces.

At 5.6 pounds, the MCX-SPEAR LT IR stays light enough for extended handling while maintaining the mass needed for reliable cycling with subsonic loads. The polymer grip and magazine well are sized for standard AR-15 magazines; one 30-round polymer magazine ships with the rifle. Receiver finish matches the FDE Cerakote, maintaining thermal properties across the entire platform. Forward assist, adjustable gas, and interchangeable barrel capability make this rifle a serious foundation for precision shooting, suppressed duty, or any mission where compact size and thermal management matter.

Key Features

• Cerakote Gen II IR Coating reduces thermal and night-vision signature while resisting wear and corrosion
• 9-inch cold hammer-forged 300 Blackout barrel with 1:5 twist, optimized for subsonic ammunition
• 5/8"-24 threaded barrel with Rocksett QD suppressor-ready flash hider included
• SIG Flat Blade Match Trigger with consistent, predictable break
• Fully ambidextrous controls for left- and right-handed shooters
• Adjustable gas piston system tunes performance to your load and configuration
• PCB tele-fold stock collapses to 16.38 inches for compact storage and transport
• Lightweight alloy handguard with M-LOK mounting points
• Forward assist for manual round chambering
• Interchangeable barrel design for caliber swaps
• Polymer grip and standard AR-15 magazine compatibility

Specifications

Frequently Asked Questions

What is the MCX-SPEAR LT IR designed for?

The MCX-SPEAR LT IR is built for shooters who need thermal and infrared signature reduction, making it ideal for low-light operations, night vision work, or anyone prioritizing concealment under thermal imaging. The Cerakote Gen II IR Coating reduces that signature while offering superior protection against corrosion and wear. It's also well-suited for suppressed subsonic shooting, CQB training, vehicle-mounted duty, or any role where a compact, reliable 300 Blackout platform matters.

Can I use standard AR-15 magazines in the MCX-SPEAR LT IR?

Yes. The rifle is compatible with AR-15 magazines. One 30-round polymer magazine is included with your purchase.

How compact does this rifle fold?

The PCB tele-fold stock collapses the rifle from 27.5 inches (extended) to 16.38 inches (folded), making it significantly more compact for transport in vehicles, bags, or tight spaces without sacrificing the full-length sight radius and ergonomics when extended.

Is the barrel threaded and suppressor-ready?

Yes. The 9-inch barrel is threaded 5/8"-24 and comes with a Rocksett QD suppressor-ready flash hider, allowing you to mount a compatible suppressor directly out of the box.

Can I swap barrels or change calibers?

Yes. The MCX-SPEAR LT IR features an interchangeable barrel design, so you can swap calibers if you have compatible barrel assemblies and perform the appropriate maintenance and adjustments to the gas system.