I dont get the idea of moving targets though, i aim infront of the running enemy all the time and once in a blue mood score a hit.
Can someone shed some light on this one?
Yeah. There are several different techniques, but I like using one that uses the target's own body to act as a ruler and a reference point. This is how I was taught to do it in the army:
In the image, the two columns of pictograms are a man running at full speed side ways, and a man walking sideways. The top row shows how you calculate the lead. You visually 'measure' the distance between the centre line (the left most blue line) and the front knee (the second blue line). The knee is the correct lead for 100m. You double that (third blue line) for 200m and triple it for 300m.
No matter what speed he is going, the distance between that front knee and the centre line will always scale like this. Not only that, but if they are not running straight across, but obliquely towards or away from you, the apparent distance will also scale.
To maximise the chance of an effective hit on the target, you should aim to hit the hips. Because the front knee and thigh are only horizontal at full pace, you should raise the sights to have the aim point at the same level as the hips, rather than pointing directly at the knee. The 2nd through 4th rows of pictograms show the aim point calculated from the knee. If the sight is set to the correct range, this is where you aim. If it is not, calculate the drop required to get the bullet to hit that spot and offset the aim manually.
Combine this technique with the range finding one, and you should be able to estimate the range based on the fall of shot, adjust the sight and try again if you miss.
I use this method in the game all the time, and it works for me. The beauty of it is you need nothing but sight of the target. You do not need any known reference points so you can use it on a map you've never even seen before. My best has been a 258m full sprint running man killed with a single 3 round burst from the DP-28.
This is a proper military technique for killing human beings. You see so many people giving advice that actually have no idea how to target a human being. They have learned to shoot at a civilian target range where they are told to never point it at a human, and are most certainly NOT told how to properly lead a running one.