An apparatus includes a body assembly with a handle (300) and a shaft portion, an end effector with a staple deck fixed to the shaft portion, an anvil, and a firing assembly. The end effector further includes a trocar and a staple driver both configured to actuate relative to the staple deck. The staple driver can actuate a distance between an unfired position and a fired position. The trocar can couple with the anvil to define a gap distance. The firing assembly includes a trigger (304) pivotably coupled with the body assembly via a first pivot (305), a driver actuator (316) configured to actuate the staple driver, and a linkage assembly (320) pivotably coupled with the trigger via a second pivot (330) and the driver actuator. Where the second pivot is proximal relative to the first pivot. The linkage assembly can drive the driver actuator is response to the trigger pivoting about the first pivot.