The SIG SAUER MCX Rattler LT is a semi-automatic pistol chambered in .300 AAC Blackout with a 7.75-inch cold hammer forged barrel and a folding pistol brace. The frame is black anodized aluminum. It ships with one 30-round magazine and has fully ambidextrous controls. Weight is 5.8 lbs and overall length is 24.75 inches. 
 

Key Specifications: 

• Manufacturer: SIG SAUER 
• Model: MCX Rattler LT Pistol 
• Type: Semi-Auto Pistol 
• Action: Semi-Automatic 
• Caliber: .300 AAC Blackout 
• Barrel Length: 7.75 inches 
• Overall Length: 24.75 inches 
• Capacity: 30 rounds + 1 (includes one magazine) 
• Weight: 5.8 lbs. 
• Finish: Black Anodized Aluminum Frame 
   

Detailed Features: 

The cold hammer forged barrel contributes to good service life and consistent accuracy. Ambidextrous controls — charging handle, magazine release, and selector — work equally well for left- and right-handed shooters. The folding pistol brace reduces the overall footprint for storage and transport. No fixed sights are included; the optics-ready top rail accepts most standard mounts.

The MCX Rattler LT in .300 Blackout is well-regarded for its compact size and the versatility of the cartridge — .300 Blackout handles subsonic and supersonic loads effectively, which matters for suppressor users. Build quality comments are consistently positive, and the ambidextrous controls get specific praise. Recoil at 5.8 lbs is manageable.

With supersonic loads and no suppressor, noise is noticeably louder than larger-platform rifles. Price sits at the upper end, and some potential buyers weigh that against similar options. Parts availability and aftermarket compatibility have come up occasionally, and customer service experiences with SIG appear mixed in forum discussions.