To counteract flinching I tell myself, its going to recoil, it'll be loud, but it wont hurt, and force myself to take it steady, sort of a" let it happen" approach. Some people say the shot should surprise you-- once you become familiar with a weapon, you know exactly when its going to fire. I think its better training to deal with recoil than to psych yourself out of it. If I had to put numbers to it, 65% mental, 30% physical, 5% luck. Physical training is very important, imho. I like to tense my hand and try to move only my trigger finger, its also good practice to aim in and dry fire, and produce good muscle memory. That said, if you can't convince yourself that you don't need to counteract the recoil, all of that physical training is no good to you.