Recommended Use: Full-Size 5" .45 ACP shooting 185 gr. / 200 gr. standard pressure target or JHP self-defense ammunition with a power factor of 145,000 to 170,000 (Velocity x Bullet Weight = Power Factor) / Average Service Life: 3,000 Rounds / Wilson Combat Heavy-Duty Recoil Springs are made combat tough to repeatedly take a pounding yet show remarkably consistent performance every time a round is fired. / Keeping a fresh recoil spring in your pistol will dramatically reduce the pounding your slide and frame receive. Mfg: Wilson Combat