I know the problem you speak of. Many a times I've shot a person in the head and it didn't kill 'em (no hit indicator even) but even more times have I hit people in the head and it be a 1 hit kill so I don't know what the problem is... wack hit boxes? unregistered hits? or maybe I'm missing by centimeters...

But I like the fact that snipers aren't perfect for now because they damn are close! I'm talking about the infinite ammo man!

semi on topic: I'm one of the rebels who camp in that tower you speak of

semi on topic 2: I love the Unlockable sniper in 2142! and I've made two realy fun games with them.
1 is to just snipe long range from different hieghts and figure out how much the bullet drops before it hits (one time I was on a minsk building fighting another sniper who was on a slightly taller building ~150 meters away and it took me until my last shot to figure out precisely how the drop worked when shooting at an upward angle... doing this while being shot at by said sniper was intense!)
2 THE BEST GAME EVER: find a server with FF on, locate an enemy flag/silo, locate a person laying down mines/c4 and either shoot the explosives while they are putting it down OR wait for a team mate to walk by and shoot it. Insta-teamkill for that poor engineer