SIG Sauer MCX Rattler LT SBR 5.56 NATO
Model: RMCX-556N-7B-LT-SBR
SIG Sauer MCX Rattler LT SBR 5.56 NATO
Model: RMCX-556N-7B-LT-SBR
Full Specifications
Threaded 5/8x24 barrel: compare 5.56 / .223 suppressor prices.
About This Firearm
The SIG Sauer MCX Rattler LT SBR is a piston-driven 5.56 NATO short-barreled rifle built for truck or pack carry and home defense. It has an MSRP of $2,519.99. Its 7.75 inch barrel and folding stock make a 25.9 inch rifle, and the gas system adjusts to suit a suppressor.
The receiver carries both M-LOK and Picatinny mounting, so an optic and a light go on without a trip to a gunsmith. One 30-round polymer magazine comes in the box. The barrel is threaded 5/8x24 on a tapered shoulder, and there is no forward assist, so a round that will not seat is cleared with the charging handle.
If you're cross-shopping, the SIG Sauer MCX Rattler in .300 Blackout is no longer made and is a used buy. It shares the same muzzle thread, with a 5.5 inch barrel, 23.5 inches overall and 5.7 lbs on a 1:5 twist. The SIG Sauer MCX Spear LT has an MSRP of $2,619.99 and a 16 inch barrel threaded 1/2x28, so a mount set up for the Rattler LT does not move across to it.
Best For
Strengths & Limitations
- The barrel is cold hammer forged steel, and the 1:7 twist suits bullets across the 5.56 range.
- The receiver is black anodized, a hard finish for a rifle that goes in and out of a bag.
- The trigger is SIG's flat blade Match unit, a flat shoe that gives the finger one place to sit.
- A 5.56 suppressor or brake cut for 1/2x28 needs an adapter before it will go on the 5/8x24 muzzle.
- A 7.75 inch barrel leaves 5.56 short of the velocity it needs past close range.
- It comes with one 30-round magazine, so a spare is an extra buy.
Compatible Ammunition
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Frequently Asked Questions
What does folding the stock do to the package?
It takes the rifle from 25.9 inches to 18.1 inches, short enough for a pack or a short case. The stock has to be out to shoot, so folding is for carrying.
What is a tapered shoulder thread?
The shoulder behind the thread is cut as a cone, and a suppressor mount or muzzle device seats on that cone. It centers the device on the bore and brings it back to the same place each time it goes on.
Can the gas setting be left where the suppressor wants it?
No. The setting matches the gas the rifle is seeing, so taking the can off and leaving the valve where it was gives the action less gas than it needs.
