Timney SIG MPX Drop-In Trigger

The Timney SIG MPX drop-in trigger is the most-installed aftermarket trigger on the platform and the upgrade Sig owners reach for once they get past the optic and charging handle. The factory MPX trigger has a heavy, mushy break that drags down an otherwise excellent gas-piston PCC. Timney replaces the entire fire control group with a self-contained module: machined alloy housing, heat-treated steel internals, and a factory-tuned 4.5 lb single-stage pull with virtually zero creep.

Installation is genuinely drop-in. Push the factory FCG out, drop the Timney module in, replace the pins. No fitting, no adjusting, no sear stoning. The hardened steel bridge inside the housing protects the trigger components from the high bolt-blowback velocities common to pistol-caliber carbines, which is the failure mode that kills cheaper drop-ins on PCC platforms.

Timney offers the MPX trigger in straight and curved bow profiles, both at the same price point. The straight bow shortens trigger reach by roughly 0.1 inch and is the preferred choice for competition shooters who run a high grip; the curved bow stays closer to the factory feel. All variants ship with Timney's lifetime warranty. The trigger is currently the recommended upgrade in nearly every MPX owners' guide and forum thread, including the SigTalk MPX aftermarket reference and r/MPX upgrade threads.