Wilson Combat TTU Trigger Features All internal components including the hammer trigger and disconnector are precision CNC machined and EDM cut from solid bar stock and manufactured from H13 steel then heat treated for maximum wear resistance under the high cyclic demands of pistol caliber blowback actions. These components pivot on hardened steel bushings rather than directly against the receiver s pin holes meaning wear and stress are absorbed by the bushings instead of the shooter s receiver over thousands of cycles. Positive trigger reset is engineered to be short and immediate guaranteeing a fast follow-up shot without the mushy reset common on many drop-in AR triggers. The Bullet Proof design behind the TTU was extensively tested by shooters specifically to withstand the unique stresses that pistol caliber blowback carbines place on trigger components. This 9mm-specific TTU model is compatible with standard USGI-style AR lower receivers using the common .154 inch trigger pin diameter but it is not compatible with Colt commercial rifles from 1991 to 2009 that use a proprietary .169 inch pin nor with the Bushmaster ACR. Because of its short fast reset Wilson Combat recommends a firm grip and solid hold when shooting from a bench or prone position to prevent unintentional bump firing from occurring. The pre-assembled housing means there are no adjustment screws that can shoot loose over time and no small parts to lose during installation which is a meaningful reliability advantage for a trigger that will see heavy round counts. For 9mm AR carbine owners at GrabAGun who want a genuinely reliable fast-reset trigger built to handle pistol caliber blowback demands the Wilson Combat TTU is purpose-built for exactly that job. Wilson Combat TTU Two-Stage Trigger Specifications Brand: Wilson Combat Fits: AR-15 Caliber: 9mm Trigger Style: Two-Stage Available At: GrabAGun