The SIG MCX Rattler LT 5.56 SBR is a compact, do-it-all rifle built on the proven MCX platform and engineered for shooters who need serious capability in a package that handles tight spaces. This short-barreled rifle combines full ambidextrous controls, a cold hammer forged 7.75-inch barrel, and a short-stroke piston system designed to run both suppressed and unsuppressed—making it equally at home in a patrol vehicle, a defensive scenario, or the range.
Built around modularity, the MCX Rattler LT accepts any MCX barrel and handguard, so you can reconfigure calibers and setups without swapping the entire upper. The SIG flat-blade two-stage match trigger gives you crisp control, while the included SIG suppressor-ready flash hider means you're already set up for a can when you're ready. Fully ambidextrous bolt catch, bolt release, and controls mean it works flawlessly for lefties and right-handers alike—no compromises.
Chambered in 5.56 NATO with a 1:7 twist, this SBR ships with one 30-round polymer AR-15 magazine. At just 6.2 pounds and collapsing down to 18.25 inches, the Rattler LT delivers rifle performance in a footprint that doesn't fight you in confined quarters. If you're looking for a short-barrel 5.56 that punches above its weight class and adapts to whatever you throw at it, the MCX Rattler LT is the real deal.
| Caliber | 5.56 NATO |
| Barrel Length | 7.75 inches |
| Barrel Material | Cold Hammer Forged Carbon Steel |
| Twist Rate | 1:7 |
| Overall Length | 25.75 inches (extended) |
| Collapsed Length | 18.25 inches |
| Height | 7.4 inches |
| Width | 2.25 inches |
| Weight | 6.2 pounds |
| Action | Semi-Automatic, Short-Stroke Piston |
| Trigger | SIG Flat-Blade Two-Stage Match |
| Grip | PDW-style |
| Magazine Capacity | 30 rounds |
| Magazine Type | AR-15 compatible |
| Accessory Rail | M1913 Picatinny |
| Included Magazine | One 30-round polymer magazine |
| Flash Hider | SIG Suppressor-Ready (QD compatible) |
Yes. The MCX Rattler LT is fully compatible with all MCX barrels and handguards, so you can easily reconfigure the rifle for different calibers and setups without replacing the entire upper receiver.
Yes. The SIG MCX Rattler LT comes equipped with a SIG suppressor-ready flash hider that features quick-detach (QD) capability, so you're ready to mount a suppressor when you're ready to add one. The piston system is also optimized to run suppressed.
The short-stroke piston design allows the rifle to run reliably both with and without a suppressor, giving you flexibility in how you use it. It also helps manage gas cycling and recoil impulse, contributing to accuracy and control.
The MCX Rattler LT ships with one 30-round polymer magazine and uses standard AR-15 compatible magazines, so ammunition and magazine availability are not an issue.
Firearm Shipments:
To buy rifles or shotguns, you must be 18 years old, and for handguns, actions, or receivers, the minimum age is 21. By placing an order for this firearm, you confirm that you are the legitimate transferee/buyer, meet the legal age requirements, and comply with all Federal, State, and local laws and regulations necessary to purchase this firearm.
We only ship firearms to valid Federal Firearms License (FFL) holders. At checkout we provide a FFL locator for your convenience.
We will need a copy of the FFL’s license to facilitate the process, kindly request your dealer to email us a copy of their FFL, as we cannot dispatch the firearm until we receive this document. It is imperative for the buyer to choose their FFL dealer, ensure they are willing to facilitate the transfer, and have them email their FFL copy to BOSQUE Outdoors. To avoid any confusion, the customer's name or order number must be mentioned in the email containing the FFL.
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