I needed to place a lighter spring in my whole sized M16 A2 clone however it ran good. Experimented with yet again Together with the eleven.5" Comando Colt upper. No dice. Ran 500 rounds of wolf through it currently. Didnt damage the spring at all. If You are looking for https://frt-trigger34567.wikipublicist.com/5545416/5_tips_about_rare_breed_frt_trigger_you_can_use_today