Here is the full list of all 10 Aim Trainer X achievements.
hit the center 1000 times
hit the center 500 times
finish a round with 100% accuracy
check your stats menu
play sniper mode 10 times
miss every shot in a round
have your reflex be under 100ms in one hit
hit the center 100 times
hit the center 10 times
Hit the center for the first time