SIG Sauer MPX-PSB — Next Generation Civilian PDW
In military and LE circles, a PDW (Personal Defense Weapon) is a compact, select fire weapon that falls somewhere in-between a submachine gun and an assault rifle. In civil terms, it means a semi-automatic vision, more than likely with a pistol with a brace. It means a SIG Sauer MPX-PSB.
The SIG is a tactical-looking weapon because it has a military/LE weapon ancestry that is especially noticeable due to the magazine mounted in front of the trigger guard and not in the grip. Initially, there is an awkwardness shooting pistols such as the SIG MPX. It feels like an SBR (Short Barrel Rifle), yet it does not have a stock for a steady aim. The SIG MPX requires a two-hand hold—very different from a typical handgun. I’ve put in a lot of range time with braced pistols, and fully believe proper training and time is all that is needed to master these large pistols. The SIG also uses a short pushrod gas system.
The MPX-PSB is based on an AR-15-style platform, except it uses a closed, fully-locked short-stroke, pushrod gas-operated mechanism. If you are an AR shooter, you will quickly adapt to the SIG, since controls and handling are similar.
The MPX-PSB is built with an upper and lower receiver, so take down is similar to an AR-15. In the lower, the bolt release, magazine release, and safety selector are ambidextrous and easy to manipulate. The lever and button “touch surfaces” are finely serrated. It is equipped with SIG’s comfortable pistol grip with textured side panels and coarsely serrated front and rear straps.
The magazine well is well flared to suck in the translucent magazine. The magazine was easy to load—even to the 30thround—and had a pebble texture on the sides with serrations on the front and rear edge. Not enough to snag in a mag pouch, but enough for a sure grip. It also had metal feed lips.
The trigger guard is oversized and glove friendly. The rear of the lower has a quick detach socket and a small rail to attach a brace. The trigger is single stage and broke at about seven pounds on average.
The upper offers 14 inches of top rail where the folding front and rear sights attach. The sights deploy and fold without pressing a button. A detent keeps them up or down.
There are two rear apertures, which are adjustable for windage. The front sight is a post-adjustable for elevation. It is protected by wings. Since buttons are not required to deploy or stow the sights, the sights can easily fold back—if the weapon is accidentally dropped.
The KeyMod handguard allows the user to mount accessories on five different rails. A hand stop is mounted behind the muzzle. The barrel is free floated and capped with an A2-style flash hider that can be removed to add your choice of muzzle device. The eject port is sized to fit a 9mm round and includes a dust cover. The SIG uses an oversized charging handle similar to an AR-15. Charging the weapon was as easy as nearly any AR-15 pistol. The SIG was easy to disassemble and clean—just like an AR-15.
At the range, the SIG showed some excellent accuracy. With Aguila 115-grain FMJs, my smallest group measured 0.54 inch. The other ammo brands were just slightly larger. On average, I found the SIG capable of 5-shot groups under one-inch. A red dot or reflex sight would shrink groups even more, but these are good iron sights and optimal for the distance most likely to be used with the pistol.
|SIG SAUER MPX-PSB, 9MM, MSRP: $1,700|
|Action Type||Short-stroke pushrod gas system|
|Overall Length||16.85 in.|
|Overall Length w/ Brace||25.75 in.|
|Overall Height||11.0 in.|
|Maximum Width||2.0 in.|
|Weight Unloaded||6.0 lbs.|
|Weight Loaded||6.8 lbs.|
|Upper Receiver||Forged 7075-T6 aluminum|
|Lower Receiver||7075-T6 aluminum|
|Barrel||8.0 in., 1:10 Twist|
|Muzzle Device||A2, 13.5×1 LH Threads|
|Pistol Grip||SIG AR-style|
|Handguard||SIG aluminum KeyMod|
|Magazine||(1) 30-round polymer|
|Rear Sight||Steel, folding, Windage Adj.|
|Front Sight||Steel, folding, Elevation Adj.|
|Safety||Ambi., 2-Pos. Lever|
I ran the SIG with and without the brace. The nice feature of the SIG is the brace can be folded out of the way. The pistol can be fired with the brace folded or extended. Reloads were fast, since the SIG had a gaping mag well. The bolt locked back on last round fired. Inserting the magazine with my support hand, and slapping the bolt release button with my support hand thumb, was smooth and fluid. The polymer of these magazines seemed to be slicker against the metal.
All controls worked with authority and ease. I got into a nice rhythm with the SIG, grasping the handguard like I would on an AR-15. I ran the SIG hard firing one and two-handed, on its side, and upside down. No jams of any kind were experienced
The SIG is well built—tight with no wiggle. Recoil was very manageable. The SIG MPX is next gen civilian PDW.
Article by Robert Sadowski