A couple of things I don't think I get.

So, I'm relatively new to War Thunder, which makes this game a bit of a hassle, and new to PC in general, which doesn't help much. So I know that many of the problems I have in game are my own fault. But there are a couple of things I don't get when playing, and I figure asking about them might make me a slightly more useful teammate. So hear goes.... 1. Ammo Racks: I understand that in the hit camera, if a piece, or pieces, of ammunition turn black, they have detonated. I've been killed many times by this, as I should. But there have been a few cases where I've shot an enemy's ammunition, had it "detonate", but it didn't kill him. Case in point: I put a shot into a T29's lower glacis once, and had the entire first row of ammo turn black, but not only did he not die, his next shot hit my ammo, turned only one black, but killed my tank. My question: Does this have anything to do with the type of ammo (APHE vs. APCR), or the piece of ammo it hits (Projectile vs. Propellant)? And if so, does changing the ammo type help? 2. Snapshotting: This is probably more my own inexperience than anything, but I've always had a hard time pulling off those amazingly quick shots right after moving. It may come from my previous experience on WoT Console, where you had to wait a few seconds before firing, or you'd likely miss. But whenever my tank stops, the gun bounces wildly (Especially in my Hellcat). Any advice as to how to improve, or do I just take the shot as soon as I see something, and hope for the best? I'm more than aware that the answer will most likely be "Get Good", but any help or resources would be greatly appreciated.