Crossfire Sniper Matches

Basically i am absolutely shit with a sniper and have no idea why, in most games i'm pretty handy with a sniper, its just even though the crosshair is right on someone it just never hits, my average sniper match will end like 10/40 (most of them probably knife kills!) or something and in standard deathmatch it would be closer to the other way round.

If i face a wall and shoot twice without moving, the holes will be in different places by quite a difference sometimes. I sometimes get the feeling that with ranged shots there could be a ping issue or something and they aren't where why shots are firing.

I'm just wondering if there anyone else has had/having a similar issue and if they have any tips for getting round it, i have lvl 2/3 badges in every other class other than sniper and having elite badge would be pretty kick ass but cant get the kills up.

Any tips/possible solutions would definitively be a massive help.

Cheers Guys!