Warning for the following sniping is something that many may be able to do, but only few will be able to master.

Steps to create a sniper class:

1. The gun I recomend is the Barrett .50 Cal

1.1  For Hardcore, I personally recommend, the Intervention.  This is 98% guarunteed to be a 1-shot kill from any distance on any part of the body w/ only a silencer and using cold-blooded. The 2% is usually because some ***hole is using painkiller, last stand, or its one of those extremely rare wtf-happened-there moments.  The Barrett, unfortunately is equipped with a only a silencer w/cold-blooded, its about a 70% one shot kill on the upper body, and maybe a 90% one shot kill when you shoot the head.  Also in hardcore if youre sniping are you really going to need to sqweeze of 2 rounds within 2 seconds on 1 target (if you answered yes, you should not be sniping, because you suck), the intervention is bolt action, meaning naturally youll take the extra millesecond to line up that shot.

2. Your perks should be scavenger, so you don't run out of ammo, and stopping power, as it makes most shots one hit kills. 

2.1  For Hardcore, i would mix it up to Cold-blooded (Cold-blooded in hardcore is like using a condom during a one night stand, it may not 100% effective from impregnating that hoe, but for the most part it gets the job done effectively). Then i would select Bling, because if you serioulsy need to have scavenger because youre spazzing out with the trigger, switch back to an assault rifle. i personally reccomend using silencer with a heartbeat sensor, on hardcore i guaruntee most will be using cold-blooded also, so thermal is basically useless.  Also many (but some still will) wont use ninja, so heartbeat sensor is a great way when you dont have the radar to use.  the last perk is ninja, with coldblooded and ninja, you can be a ghost, if you dont have ninja yet, use steady aim.

3. Side arm, should be a shotgun when someone gets close a shotguns your best bet.

3.1 In Harcore a well placed pistol shot to the head or 2 to the body, will put any man down, so i reccomend the USP. 45, because it can be silenced (silence is golden!)  also it has a nice rate of fire, and is very accurate, even more accurate with the silencer, in my opinion, only sacrificing a small rate of fire.  If you have Bling Pro, use fmj and silencer.

How to snipe

One thing you should know about sniping, don't stay in one spot, the longer you stay there the more likely your enemys will discover you. 

 in hardcore you only have to think about moving, if you shot and missed, and the guy fired back at you but you killed him, or if you missed but killed him  the second shot, but he was looking your direction.  You do not have to move if you shot him in the back of the head, or wasnt clearly looking at you.

Remeber when you kill a person they can see you in killcam,  (Unless you're playing Hardcore).

A part of being a sniper is being able to stalk your prey. If you can keep your eye on them, you can possibly find their team mates, and then you have a nice amount of kills waiting for you.

Learn sniping spots, every map has them.

Hold your breathe to do so hold down L3. It will steady your aim and you will have much better accuarcy.

When possible gillie up. Gillie can be a great option, as you are very hidden, but just remeber, most people know that leaves and stuff like that don't move, if they see you do it they'll know your an enemy. And also make sure your gun's camo matches with the map, if your on a desert map with desert gillie, don't have arcitc camo you'll really stick out.

With these tips I hope all snipers can improve, and all soldiers can be snipers.

Now if you'll excuse me, I have a head in my sights.