Action Enhancement Trigger Kit for M&P

This Action Enhancement Trigger Kit is a drop-in replacement assembly designed for Smith & Wesson M&P pistols in 9mm or .40 S&W. It addresses the factory trigger’s inconsistent pull weight and long, gritty reset by reducing pull weight to a repeatable 5.0–5.5 lbs. range and shortening both pre-travel and over-travel by approximately 20%. The result is a smooth uptake, a crisp break, and a reset that tracks shorter and more positively—no frame modifications or armorer fitting required.

Compatibility

• Smith & Wesson M&P9 (all generations)
• Smith & Wesson M&P40 (all generations)
• M&P Shield, Shield Plus, and M2.0 Compact variants are not compatible
• Requires 1/8″ sear plunger and spring. If your pistol has a 1/16″ sear plunger, upgrade to a modern sear housing block before installation.

Key Features

• Pull weight: 5.0–5.5 lbs. (approx. 1 lb. reduction from factory)
• Pre-travel / over-travel reduction: ~20% reduction in both directions
• Trigger break: Crisp, with no stacking or creep
• Reset: Shorter, more tactile, and audible
• Safety: Center-mounted pivoting safety maintains factory drop-safety values
• Installation: Direct drop-in; no fitting, stoning, or frame modification needed

Install Difficulty

Level: 2 of 5 – Basic hand tools required (punch set, small hammer, bench block). Detailed instructions included. Armorer experience helpful but not required. Verify your sear plunger diameter before starting.

FAQ

Will this work with my M&P Shield?

No. This kit is designed for full-size and compact M&P9 and M&P40 frames with a standard sear housing block. Shield and Shield Plus models use a different trigger system.

Do I need to modify the frame or trigger bar?

No. All components are drop-in replacements. No filing, polishing, or fitting is required. Follow the included instructions for proper orientation of the sear spring and plunger.

What if my M&P has the older 1/16” sear plunger?

This kit is tested and guaranteed to function only with the 1/8” sear plunger and spring. If your pistol uses the smaller 1/16” plunger, you must upgrade to a modern sear housing block (available from Brownells or other retailers) before installing this trigger. Function and reliability cannot be assured with the older plunger system.

Shipping & Warranty: Free shipping on orders over $75. This component is covered by a limited lifetime warranty against manufacturing defects. Installation is the responsibility of the user; improper installation or use with incompatible parts voids warranty. Always verify safe function with dummy rounds after installation.