SIG Sauer MCX Rattler 5.56 NATO Pistol, 6.75" Threaded Barrel, Short-Stroke Gas Piston, Side-Folding Brace
This SIG Sauer MCX Rattler in 5.56mm NATO pairs a compact 6.75-inch threaded steel barrel with the MCX short-stroke gas piston system and an adjustable gas regulator. An internal recoil system enables true side-folding operation with the included brace. The aluminum free-float handguard features an integral QD sling socket and a continuous 1913 Picatinny top rail, delivering a compact, purpose-built package made in the USA.
Condition
Overall Condition: Very good condition, showing only light, superficial signs of prior handling or use.
Bore Overall Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Details: This firearm is in great shape overall. Minor scratches and blemishes are present on exterior surfaces.
What's Included
- Original box
- Paperwork
- 1x 30-round Magpul PMAG AR/M4 pattern polymer magazine marked 5.56x45
The Rattler configuration delivers a very compact 5.56mm NATO platform built around a 6.75-inch threaded steel barrel capped with a three-prong flash hider. Its short-stroke gas piston operates with an adjustable regulator marked with plus/minus indicators, allowing the user to tune the system as needed.
An internal recoil system eliminates the need for a receiver extension, enabling true side-fold operation. The included brace folds to the side and uses a skeletonized strut with a hook-and-loop cuff for streamlined carry and rapid deployment.
The aluminum receiver set and short free-float handguard keep weight down while maintaining rigidity. The handguard integrates a QD sling socket and elongated slot cutouts for ventilation, with a continuous 1913 Picatinny rail across the top. This configuration omits a forward assist for a clean, compact upper profile.
Controls are straightforward and familiar, including a manual safety selector and a curved trigger shoe. The pistol accepts STANAG/AR-15 magazines and ships with a 30-round PMAG. Markings include "RATTLER" on the upper, "SIG MCX MULTI-CALIBER" on the lower, and an ejection-port cover stamped "MULTI-CAL," along with the manufacturer mark "SIG SAUER INC NEWINGTON NH USA."