WOLFF M&P XP Recoil Calibration Pak is designed for full-size 9mm, .40 S&W, and .357 SIG pistols and includes a range of recoil springs to customize firearm performance.
The kit provides recoil springs of different weights (17, 19, 20, 22, and 24 lbs) to adjust for load strength and recoil management, enhancing reliability or speed in competition.
Each recoil spring in the calibration pak comes with a factory weight striker spring, and the springs require a full-length, non-captive guide rod.