Huge difference between shooting scaled targets & shooting at "for real" distances.
Steady hold, breathing, trigger pull, all that matters, no matter the distance, but schwacking the bull at 400m, with an M16A1 & open sights is a whole 'nother ball game.
Used to shoot on my Battalion's small bore team. Temperature & especially wind become big factors. We spent 2 or 3 days/wk, sweating on that range, for a month straight, getting ready for a shoot.
We shot 10 rds, rapid fire, mag switch standing at 100m, same drill sitting at 200m, same drill kneeling at 300m (might have the 200 & 300m positions flip/flopped) & 20 rounds, slow fire at 400m.
That kinda shootin' is TOUGH, fellas, but some of y'all already know that