With the ATF brace rule being vacated, SIG SAUER is back in the braced pistol game. They just launched two new M400 pistols with some great features. The M-400 Tread and M-400 SDI X pistols. Both are AR pistols based upon SIG’s proven M-400 DI platform.

M400-TREAD Pistol

The M400-TREAD Pistol is chambered in 5.56 NATO and has a 11.5-inch cold hammer forged steel barrel fitted with a three-prong flash hider. It uses a carbine gas system and has a lightweight, free-floating M-LOK enhanced handguard.

The M400-TREAD’s lower receiver is fitted with an ambidextrous safety and has an integrated QD mount for sling attachment. It has a SIG Matchlite 2-stage trigger, and it comes with a Magpul BSL telescoping brace. The M-400-TREAD Pistol ships with one 30-round magazine to states that allow such freedom. No MSRP has been listed at this time.

M400-SDI X Pistol

The M400-SDI X Pistol has similar features to the TREAD but some updates as well, based upon input from instructors at SIG SAUER Academy. It’s also chambered in 5.56 NATO with a cold hammer forged 11.5-inch barrel with a carbine gas system but has a free-floating handguard that uses a new steel lockup design that SIG says “significantly reduces handguard deflection by providing maximum rigidity and allows for accessories to be attached on all four sides with no effect on accuracy.” The barrel on the M-400-SDI X is fitted with a hybrid compensator/flash hider. Or remove the compensator and install your favorite suppressor.

M-400-SDI X adds fully ambidextrous controls, including a bolt catch/and release unique to the M400-SDI lower receiver, as well as an ambi charging handle and mag catch. It has an upgraded 2-Stage Matchlite Duo flat trigger trigger that gives 4.5- to 6.5-pound pulls, right out of the box. Like the M-400-TREAD it comes with a Magpul BSL telescoping brace and ships with one 30-round magazine. MSRP is not listed on this one just yet either.

If you’re in the market for a new factory-built braced pistol then head on over to SIG SAUER for more info. These things should be available for sale very soon.

Where To Buy

Sig Sauer M400-TREAD Pistol

Sig Sauer M400-SDI X Pistol

Magpul BSL Arm Brace – Mil-Spec

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