Footage from early in the Syrian War shows a group of anti Assad rebels filming a three tank element, when they are discovered and engaged with accurate main gun fire.

As the rounds come in, their impacts can be seen in the foreground, causing panic among the rebel group. Luckily for them, anti armor tank munitions aren't all that effective against troops in the open, save for a direct hit. Based on the time between the shot and the impact, the armored column is firing approximately four to five kilometers.