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HomeVideosAR PistolsThe SIG MPX PCC

The SIG MPX PCC

· September 27th, 2025 · AR Pistols

This video examines the SIG MPX pistol caliber carbine with a focus on construction, controls, and handling. It also verifies factory specs for weight, dimensions, and trigger pull.

Featured In This Video

Sig Sauer MPX K, Semi-Automatic Pistol, M-LOK, 4.5" Barrel, SIG Folding Brace, Timney Trigger - PMPX4B935 Specifications

manufacturerSig Sauer
TypePistol
Caliber/Gauge9mm
ActionSemi Automatic
Mag Capacity35
Barrel Twist1:10
Barrel FinishBlack
Threaded BarrelYes

Video Summary

Read the full transcript

Overview and Technical Specifications

The video introduces the SIG MPX as a pistol caliber carbine that sits on the higher end of the price range but offers a feature-rich, well-built package. The host outlines the plan to cover technical specifications, then walk from muzzle to brace, and finally verify SIG’s listed specs. The MPX is chambered in 9mm and uses a 4.5-inch carbon steel barrel with a 1:10 twist rate. It is semi-automatic and uses a gas piston operating system with AR-style controls. The gun is configured as a pistol with a brace and uses MPX-specific magazines. Factory specs list an overall length of 22.25 inches, width of 2.4 inches, height of 8 inches, and a weight of 5 pounds, though the video later checks whether that weight includes a magazine.

Controls, Materials, and Ergonomics

From the muzzle back, the SIG MPX features an A2-style birdcage flash hider and a full-length Picatinny rail on top for mounting optics, lasers, or lights. The handguard provides M-LOK slots on the left, right, and bottom, allowing accessories to be mounted off the top rail if desired. The charging handle is ambidextrous and similar to a standard AR pattern. The upper receiver assembly, including the handguard and both receivers, is aluminum, while the pistol grip and some other components are polymer. Controls are fully ambidextrous, including the safety selector, magazine release, and bolt release, giving familiarity to AR users. A noticeably flared magazine well helps guide MPX magazines during faster reloads, especially under pressure.

Trigger Characteristics and Grip Details

The MPX is equipped with a flat-faced trigger that the host describes as having virtually no take-up. When the trigger is pressed, it immediately meets a defined wall, then breaks with what feels like roughly 4 to 5 pounds of pressure. The reset is short, tactile, and returns directly to the wall with no additional slack, supporting rapid follow-up shots. The pistol grip is polymer with light to moderate texturing on the sides and additional texture on the backstrap. A small lip at the bottom of the grip helps keep the hand from sliding off, which can be useful in hot or sweaty conditions. The grip also incorporates a small storage compartment sized for items such as compact oil bottles or other small accessories.

Brace Design and Operation

The SIG MPX shown uses a SIG folding brace with a matte finish that matches the rail, handguard, and receiver. The overall matte texture across the gun provides a bit of extra grip when handling. The brace operates via a button that must be pressed while pushing or pulling to fold or extend it, which is demonstrated as easy to use once the motion is memorized. Under stress, missing the button could slow deployment, so familiarity with the mechanism is emphasized. When extended, the brace can be used to stabilize the pistol against the shoulder pocket. The brace has a small amount of movement, but this can help the shooter slightly cant or twist the gun more comfortably while maintaining contact.

Verifying Weight and Overall Length

The host verifies SIG’s published weight figures using a scale. With a magazine inserted, the MPX weighs 5.34 pounds. Without the magazine, it weighs 5.05 pounds, which explains the rounded 5-pound specification. The weight remains consistent whether the brace is folded or extended. Length is then checked with a tape measure. With the brace extended, the gun measures approximately 25 inches overall. Measuring from the muzzle device, the length comes out to about 22.25 inches, which aligns closely with SIG’s listed overall length. These checks confirm that the factory numbers are generally accurate, with only minor differences attributable to rounding and how the measurements are taken.

Height Measurements and Trigger Pull Data

Height measurements are taken to compare with the listed 8-inch spec. With the magazine inserted, the height is around 10.5 to 11 inches. Measuring from the grip area without relying on the magazine, the height is closer to about 7.5 to 7.75 inches, suggesting SIG’s 8-inch figure is slightly conservative. The trigger pull is then quantified using a gauge. Multiple pulls on the flat trigger produce readings of 3.56 pounds, 3.11 pounds several times, and 3.72 pounds. Overall, the trigger averages just over 3 pounds, lighter than the initial 4- to 5-pound estimate based on feel. This confirms that the MPX’s trigger is relatively light, with a consistent break and reset suitable for quick, controlled shooting.

Closing Thoughts on the SIG MPX PCC

The video concludes by summarizing the SIG MPX configuration shown, emphasizing the brace-equipped 9mm PCC format, ambidextrous AR-style controls, flared magwell, and flat-faced trigger. The host notes that the verified weight, length, and trigger pull closely match or slightly refine the factory specifications. Viewers are invited to share their own experiences with the MPX, including reliability, handling, and range performance. Comments and user reviews are encouraged to provide additional perspectives beyond this overview. The session ends with a brief sign-off and an implied intent to take the MPX out for further shooting, underscoring that the focus of the video is practical observation and spec verification rather than promotional claims.

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