It has gotten to be normal for armor guys to declare that they are seeing inconsistent results during engagements. There are a lot of factors in play and too many for the argument to always go against the game itself. First thing you have to know is that just because you see a bright sparkly hit does not mean that it was a kill shot. The second thing you have to realize is that the game involves people from very different areas of the world and when you shoot someone there may be a lot of lag involved. I can tell you from firsthand experience that you can shoot someone, have them rotate their barrel ninety degrees, and shoot before your hit causes them to explode. The faster connection will lose in simultaneous critical hits. The other tank may die too, but you will or will not get the kill depending on lag (I think). And lastly is this latest graphic issue where you see a hit, but the appearance afterwards is like a lightsaber dancing around the impact point. I'm convinced that is the game engine establishing the direction that the ricochet will actually follow, because if you slow down the film playback of the event you will see the tracer be drawn in several different directions in consecutive frames. Of course, it could also be the projectile breaking up, so your guess is as good as mine on that one.
The one thing I don't believe in is luck. It's human nature to say it, but the fact is their isn't a giant depository of luck in the universe with an unknown entity, or force, randomly handing out luck, good or bad. If there is, well I want that job, so I can mess up the rooks all day everyday.