This trophy is most easily attempted via the AR Challenge
One Man Army (or
Untouchable) under the Batmobile Combat category which is unlocked early in the game. It is recommended that you load this up to make this trophy as easy as possible, although the same method can be applied to any area of the game. You may want to upgrade your Vulcan Gun with the precision upgrade as well prior to attempting this.
A perfect shot is attained when you use the Vulcan Gun ([cn_RB]) to get a direct hit on a light tank's weak spot with the first bullet that leaves your turret. The tank's weak spot is located on the top, near the turret directly where there is a visible glowing light. Hitting this weak spot immediately after using the Vulcan Gun will make the tank explode and grant the player with a "Perfect Bonus" or "Perfect Critical" indicator in the top left of the screen. If you miss you will instead get a "Critical Bonus" or "Critical Shot" which DOES NOT count.
You'll want to use your movement to get nice and close to the enemy light tanks, which will help you avoid missing due to weapon accuracy. Another important note is to make sure you only shoot if you are 100% certain that you will get the hit. A good method is to stalk a light tank until it stops and tries to shoot you, there will be a short moment where it stops moving and this is the best time to hit them. The trophy is awarded after 5 perfect shots in a row without taking any damage. If you mess up feel free to restart this AR Challenge until you are able to get it.