Timney AR-15/AR-10 Competition TriggersCompetition Replacement of AR-15 Fire Control Group Timney Triggers for AR-15 and AR-10 are also called the Fire Control Group. This unit replaces creepy two-stage triggers with a single stage that is smooth and crisp. These triggers are available pre-set for 3 lbs or 4 lbs pull weight (4 lbs on the AR10). Installation Instructions are easy to follow as this is a true 100% drop-in trigger with no adjustments required. The installation uses your original hammer/trigger pins and the system eliminates pin rotation and walkout. They fit ARs with "small Pin" (.152-.157) Hammer/Trigger mechanisms.