We all have a physiology to deal with, and adrenaline rush is part of the mix. Adrenaline makes fine motor skills sluggish and decreases sensitivity, making it difficult to get the same "feel" and "execution" as you have without it. There are two keys to overcoming those negative effects, put yourself in the situation and practice compensating for it, and have a bullet proof routine that you never vary from. The routine should include a mental trigger that helps you start the mental focus of doing the entire task. An example would be to tap the bolt handle with your trigger finger. From there it's all business until the shot breaks. If something interrupts, you should start over from the bolt tap, just like it was the first time.