SIG MPX K

The SIG MPX K represents the sweet spot of the MPX lineup, offering enough barrel length for reasonable velocity while maintaining compact dimensions. The 4.5-inch barrel provides approximately 200 fps more velocity than the Copperhead's 3.5-inch barrel while adding minimal length, making it the better choice for defensive applications where terminal performance matters.

The MPX's gas piston system shines in the K configuration. Unlike blowback PCCs that rely on heavy bolts and strong springs, the MPX uses expanding gases to cycle the action. This results in noticeably reduced recoil and a smoother shooting experience. Suppressor setups should be matched to the exact commercial SKU and current SIG guidance rather than assuming every MPX K package includes the same regulator details.

SIG builds the MPX K with their KeyMod to M-LOK updated handguard, providing ample accessory mounting space for lights and lasers. The Timney trigger-ready fire control group allows easy upgrade to a premium trigger without gunsmithing. For shooters who want the MPX experience without the velocity sacrifice of the Copperhead or the length of the full-size, the K delivers the ideal balance.