Never used Wolff Xp recoil and firing pin spring for Kimber 4". I bought it for a Kimber Pro Carry II. $10.00 FTF in the Houston area. if shipped I will take paypal pkus shipping. Wolff Improved XP Recoil Spring Wolff improved design recoil spring offers higher battery pressure along with a higher recoil rating, providing optimal functioning. For all Pro Carry and Compact 4" Kimber guns only.