Sig Sauer MCX Rattler LT .300 BLK AR Pistol, 6.75 in Barrel, Short-Stroke Piston, Adjustable Gas Block, Left-Folding Brace
This MCX Rattler LT pairs a compact 6.75 in .300 AAC Blackout barrel and 1:5 twist with Sig Sauer's short-stroke gas piston system and a multi-position adjustable gas block. It is configured with a Gear Head Works Tailhook left-side-folding brace and a blast-forward muzzle device. The pistol has ambidextrous controls, a full-length top rail, and arrives in excellent condition with one 30-round magazine.
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.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: There are minor, superficial scratches and blemishes present on exterior surfaces. The bore is clean and shiny.
What’s Included
- 1x 30-round Amend2 polymer AR-15 pattern magazine with "300 BLK" hand-written on body
- Gear Head Works Tailhook arm brace on 1913 side-folding mount (installed)
- M-LOK polymer handstop/short vertical-style foregrip (installed)
- Blast-forward style muzzle device (installed)
The LT submodel retains the proven MCX Rattler architecture in .300 AAC Blackout, featuring a 6.75 in barrel with a fast 1:5 twist and a detachable AR-pattern magazine system. The short-stroke gas piston uses a multi-position adjustable gas block to tune function with different ammunition.
Construction centers on aluminum alloy receivers with a hard-anodized finish and a free-float aluminum M-LOK handguard. The handguard provides M-LOK slots at 3, 6, and 9 o'clock, while a full-length 12 o'clock Picatinny rail runs across the upper and handguard. The upper receiver omits a forward assist and includes a standard ejection-port dust cover. A rear 1913 Picatinny rail interface anchors the folding brace.
Controls are fully ambidextrous, including the safety and bolt catch/release. The pistol uses a flat-faced silver trigger and a SIG SAUER polymer pistol grip. No sights or optics are installed from the factory on this example.
Factory markings include a "RATTLER" plate on the right side of the upper receiver, a lower receiver roll-mark "SIG SAUER INC, NEWINGTON NH USA," and a SIG circular logo molded into the magwell. One 30-round magazine is included, noted with "300 BLK" hand-written on the body.