Artillery, or arty/spgs, are the main firepower of the team. These self propelled guns have very large guns, meaning they can do a lot of damage per shot, this is countered by its long reload, horrible aiming times, and bad accuracy. Arty are poorly armored and dont have a lot of mobility with the exception of french arty(the french always focused on mobility, they also have the fastest aiming times, reloads, and best accuracy compared to other nations, but they also have the least damage per shot). I personally am going down the french arty and I can tell you that the french start off really bad, and get better and better(teir 9 and 10 get turrets). Most arty, with the exception of the bat chillion 155 55(teir 9 french), bat chillion 155 58(teir 10 french) and SU-26(teir 3 russian), have no turrets and therefore need to turn their hull to face the target, this makes them have to reaim their gun again. Arty also have to be wary of counter battery. Enemy arty can see the tracer of your gun when you fire and can kill you by shooting the tracer's origin(and kill you if you dont move)to counter this you sould immediately move after you fire, this usually take 10 seconds or so, depending on the mobility of the spg. Spgs have a different mode from other tank's sniper mode which is called artillery mode, this mode allows them to play the traditional artillery role(nuking people from the sky), in this mode there is a line which is colored either green, red or gray, green indicates whether its possible to hit the place you are pointing at(you still need to have the reticle to confirm the place as well), red mean that somthing is blocking the ground you are aiming at(a rock, a tank, a mountain, etc)and grey means you do not have the range to shoot that place.