When shooting competitive bulls-eye i will forgo caffeine for two to three hours prior to shooting. I will, however, pop in a dip before the 25 slow fire (pistol) and at the begining of the rifle, and one on the last (longest) of the rifle.
I do not win bulls-eye shoots.
I an however, in about the top 20% of large matches for pistol and rifle.
However, I do not really like shooting bulls-eye competitions- way too much interest in/discussion about minutia.
When it comes to IDPA/USPSA I will follow my normal routine, pretty much just not drinking Monster while shooting (water and Gatoraide instead). However, I will have a dip in almost constantly. Same for courses.
We used to go out on night patrols with our bellies and pockets full of ephedrine and red-bull. It definately didn’t put me at a disadvantage.