Sorry about the double post but I kind of want to explain the world of tanks damaging system a bit to TA, it's a little bit more in depth than trundle in, fire your gun and go. OK, you have to take into account four factors when you fire your gun and they are range, crew, slope, and resistances.
OK, range, all guns have an 'average' penetration, if a gun says it has 175 average penetration that is at EXACTLY 100 yards. It goes down by about 5% per 100 yards more than that you are away from them. so if you're 265 yards away that same gun will only have about 160 penetration.
Crew factors in accuracy and reload speed, your gun's accuracy is also at 100 yards. A gun will usually have a number like .3m off dead center at 100 yards, this goes up a bit naturally as the shell travels further but it also factors your gunner's experience in, if your gunner is at 70% he's going to have 20% less natural deviation than a gunner who is at 50%, this is the easiest thing to account for because you can just wait without moving your tank or your cross hair for a long time until you get the most accurate shot and fire. There is really nothing you can do to make your reload speed better than get your crew experience.
The third factor is the enemy tanks armor slope. Certain tanks, mostly American and German have very well sloped armor, the t-34 comes to mind, such tanks have certain points on their armor that are sloped in such a way that if you shoot them there they have up to a 20-35% chance to just bounce the shot, no matter the penetration of it. This is why when you're within 10-75 yards(Affectionately called knife fight range) you should ALWAYS aim for the flat areas of the tank.
Now about resistances, it's just knowing where to aim on certain tanks if it becomes an option. Almost ALL German tanks have less armor in the bottom 35% of their model so if it's possible you should always aim low on them. A German tank can say it have 90 side armor but you can penetrate with a 60 penetration gun if you aim at the right place on the side. Russian tanks have weak ammo racks on the backs of their turret(Even if you can't see it on the model it's usually there) and weak exhaust ports.
All in all though, you have to play tanks a bit more strategic than it first seems or you're not really gonna get anywhere, most heavier tanks have guns with a reload speed of between 4 and 7 shots a minute, so being out of commission for 12+seconds just because you fired without factoring in everything is very bad.
