Fine tune yourRadial Delayed Blowback(TM) pistol or carbine with the Action Tuning Kit.Whether you want the smoothest shooting carbine possible or are looking for added reliability while shooting hotter loads or suppressed, CMMG's Action Tuning Kit gives you the added flexibility to make your CMMGperform exactly how you like it.Small, Medium, and Large weights allow for you to test and find the right weight for your setup. There is no universal answer for which works best. Barrel length, ammo selection, and suppressed or not play a large role in determining your weight.WEIGHT SELECTION GUIDELINES:Small weight: Lightened recoil under standard loadsMedium weight: Suppressor use, or +P loadsLarge weight: Suppressor and +P loadsThe guidelines above should be used as a starting point.Included:- 1oz, 2oz, and 3oz weights- (3) .250? x .625? roll pins