An efficient anti sniper class would be the following:
2) Shocks (if you have good aim, throw it at themm instead of around them) or stuns/flashes
3) Guardian killstreak/Scentry Gun
4) Your regular class setup
Coming from a sniper (Wii Remote sniper), some of the most troubling stuff for a sniper are those things, but there are still things to counter them. Nonetheless, you can make it more difficult to snipe a player by having good aim yourself and know the sniper routes that snipers will generally take. Always be aware that there is no perfect anti sniper class. Dealing with an aggresive sniper, you can still get taken out easily if they know that they're doing.
Here's some other things to make note of:
-Sniping paths (you see them in montages and top 5 sniper plays and whatnot, usually). Be in the area, not the path.
-Stick controller players improve their speed by using high sensitivities, take note that they use the sticks to change the camera position. As long as you see them first there's a chance to win, not the other way around when playing against good players.
-For myself, as a Wii Remote sniper, all i need to know is your general area and from there i need to see just a tiny bit of the player to know where to scope towards. Even if you're a moving target, if you don't have lightweight then you make my job easier.
-You can pick up a sniper yourself and have a shot at it.
-You can try fooling around with them by running around in circles while they try to snipe you (use lightweight) and then knife them when they are turned the other way around.
-Them missing that first shot is the important part to taking a sniper out if they use bolt action.
-Range only means there's a little longer gap for a sniper to target you.
-Use your random "teammates as meatshields" (taken from a friend's strategy) and then flank to get a better angle to take them out. Works well on some maps like Carrier, however an alert sniper can still counter this, especially those surrounded by teammates.
-On raid, don't be mindless when spawning in the garage and run to the center of the map (with the large tree). I wall bang a lot of players that way Take an alternative path, but meets a similar result (enter from the side of the map with the statue or the side of the map near the pool and bar. Both have entrances to that center and by doing so you at least won't be wall banged that way.)
That's all that comes to mind at the moment, but some of these tips should at least be somewhat helpful imo.
also just noticed something, played sharpshooter and got a sniper scope on a LMG. guess what: virtualy NO fake sway. felt almost like quantom of solice nearly perfected wiimote sniping(just lack sensativity options) then i used a normal sniper, put wiimote on a on a table and it swayed like i had someone pushing against the side of the gun.