Sig MPX 9mm – Accurate Adaptation

Am Shooting Journal ^ | 10/6/20 | O Volk

[w1n1]

SIG Sauer's 9mm Pistol feels both new and familiar within the MPX line.
The MPX family of pistol-caliber firearms fixes the main flaw of close-bolt blowback designs: excessive bolt weight. Adapting the AR-15 platform to 9×19 Luger with a gas-piston action, SIG engineers cut the overall weight and the reciprocating bolt carrier in particular, making MPX lighter than other 9mm ARs and cutting the recoil intensity at the same time.
The resulting weapon is available as a 16-inch carbine, and as submachine gun, short barrel rifle and pistol, all available with 8-inch or 4.5-inch barrels.

In the carbine form, the 7.6-pound overall weight of the weapon is no different from a rifle-caliber AR-15, making it more of a practice version of the 5.56, with less expensive ammo, less concussive report but substantially similar handling and manual of arms. The shorter barrel and forend of the 8-inch SBR and submachine gun variants bring the weight down to 6 pounds, and collapsed length down to 17 inches.

The 9mm Luger cartridge generated far smaller volume of gas than 5.56x45mm, so the MPX gas port is almost right at the chamber to generate sufficient pressure for cycling. With most 9mm loads, 8 inches is sufficient to get most of the potential velocity increase from the limited case volume. With the A2 flash hider, the muzzle signature is nonexistent.

As with other gas-operated pistol-caliber guns, the MPX favors full-power ammunition for reliability – in my testing, it ran perfectly with 115-, 124- and 147-grain SIGbrand defense and range ammunition, but short-stroked occasionally with wimpy commercial remanufactured ball. With full-power ammunition, MPX has less felt recoil than blowback guns had with subpar loads.

WHEN SUPPORTED, the MPX pistol is superbly accurate. When rested on an convenient cardboard box and sighted with a red dot, the pistol shot very small groups at 25 yards, especially favoring 124- and 147-grain SIG JHP ammunition. Read the rest of Sig MPX 9mm.

[Celtic Conservative]

And I’d go buy one if I didn’t have to sell a kidney to afford it.

CC

[null and void]

Bah! You have two kidneys, cheapskate!

[TexasGator]

CC Version:

[lurk]

Looks fun for multiple targets in a smaller space.

[Mariner]

Anyone know what the street price of one of these is?

[Celtic Conservative]

You have a point...

CC