The hair trigger is often a result of the lighter trigger spring and YOU. Usually caused by still having pressure on the trigger during the down travel of the barrel during the recoil process, only taking just a little more pressure for the "hair trigger" to work. It is a pitfall of the lighter trigger spring being substuted for an action job on the gun. Or so the experts tell me. I only have two of the 8 guns that I have changed springs in that gets me that way. It can actually be somewhat of a saftey hazard to inexperienced shooters in speed shooting events. I thought it was me not paying attention to my actions and found out it was both of us, me and the spring.