SIG Sauer MCX Rattler PCB 5.56 NATO Pistol – 5.5" CHF Barrel, Folding Brace, Ambi Controls
The SIG Sauer MCX Rattler PCB brings the proven MCX piston system to an ultra-compact 5.56 NATO package. Its 5.5-inch cold-hammer-forged barrel, adjustable gas block, and fully ambidextrous controls give shooters rifle-grade performance in a platform that folds to roughly 18 inches. Built on a hard-coat anodized 7075-T6 aluminum receiver set and fitted with a side-folding polymer brace, this pistol delivers reliable function, durable construction, and easy portability in one of the shortest factory MCX configurations available.
Condition
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Bore Condition: Excellent – Clean, mirror finish, no signs of wear.
Rifling Condition: Excellent – Sharp lands and grooves.
What’s Included
- SIG Sauer MCX Rattler PCB pistol
- Two 30-round Sentry Hexmag polymer magazines
The 5.5-inch carbon steel barrel is cold-hammer-forged and threaded 1/2-28 TPI with an integral tapered shoulder that mates directly to SIG QD suppressors. A fast 1:5 RH twist stabilizes heavyweight 77-grain projectiles for extended effective range from this short platform.
Short-stroke gas piston operation keeps the action clean and reliable, while the two-position adjustable gas block lets the user tune performance for suppressed or unsuppressed fire. The free-float aluminum handguard features M-LOK slots and a continuous 1913 top rail for mounting lights, lasers, and optics.
The side-folding PCB brace reduces overall length to about 18 inches when folded, enhancing storage and maneuverability. Ambidextrous controls include the safety selector, magazine release, and bolt catch, giving right- and left-handed shooters equal handling speed.
Constructed in the USA, the MCX Rattler PCB retains the modularity of the MCX series, allowing future barrel or caliber changes with compatible components. Its compact dimensions, rugged build, and well-thought-out features make it a versatile choice for personal defense, vehicle carry, or specialized professional roles.