I hear you want to get the long distance headshots Soldier? Well I'm going to tell you how to do that.

The M98B is the most powerful sniper rifle in Battlefield 3 and in fact the world. It's got the longest range max distance of 3250M but can go a bit further if you aim higher and cant see your target in the sight. It uses a .338 Lapua Magnum round which makes it the most powerful rifle in Battlefield. Max damage is 95 until 15M before drop off start, it does 1.06x damage to the chest so you can get one shot kills to the chest up to 17.5m and as still does 2x damage to the head. The end drop off is at 150m and has a minimum of 59 damage, so headshots will still be one shot kill even at 3250M but good luck trying that. It does only have 5 rounds in a magazine and 6 when one is in the chamber with a full magazine.

It's got the third lowest RPM (rounds per minute) at 46.2 rounds, the worst RPM is the L96 at 43.5 and the JNG-90 at 46.15 rounds. The muzzle velocity is the quickest a 650M which makes up for the not so great RPM. Because of how fast the bullet travels you don't have to lead to much at the target. If a target is 650M away it will take a bullet 1 second to hit the target so you'll only have to lead a few meters a head of the target, at 150M it will take 0.23 seconds to hit. My longest headshot is just under 1300M so it took the bullet nearly 2 seconds to connect with my target head.

There is no side to side recoil just up recoil and it has a fair bit of up recoil but as it's bolt action it cant be spammed like the .50 cal in the Call of duty games. If it's got a bipod and it's deployed the recoil is a fifth and then the recoil is nearly the same as the AK-74M with a heavy barrel.

The reload times for the gun aren't to unreasonable either if you take in how good the gun is. With a bullet in the chamber it take 2.90 seconds to reload if all bullets are fired it takes 4.70 seconds to reload, this does make it the longest reloading sniper when one bullet is in the chamber, this makes it's tied with the JNG-90. 

How it should be used.

There are many ways to use this gun, when you unlock the gun with 146,000 recon score it has the 8x optics just like the rest of the US snipers, the 12x (ballistic scope) is unlocked at 10 kills which can be done in a game. The 8x is by far the best scope to use on any medium to large maps but if it's long range sniping that is needed then the 12x is the best to use. On smaller maps it's not a good idea to use this gun because it's bolt action but if it's going to be used in close combat, use a Holographic (unlocked after 80 kills) or ACOG (unlocked after 50 kills) but the ACOG might be too much on the some small maps. 

If you're going to be laying down a lot the the Bipod is the best thing to use along with the 8x or 12x because the screen is slightly bigger when ADS (aiming down sights) along with that there is no need to hold breath. 

If you're going to be on the move a lot or not going to be near any cover where a bipod can be deployed then the Straight Pull Bolt (unlocked after 60 kills) will be the best thing to use as the player can reload a round into the chamber while ADS but you'll still have to come out of ADS to reload the magazine. 

Using the gun in close combat, you'll want the Laser Sight (unlocked after 20 kills) with a low times optic sight  to get the best aim. Using the laser sight decreases the spread of the cross hair by half in any position.

I would not recommend using the Suppressor (unlocked at 70 kills) in any situation.

Overall.

The M98B is a long to very long range rifle but can be changed suit close to medium range with some practise. http://www.youtube.com/watch?v=nXNF22Ksx_U skip to 0:24 and watch to 0:53 to see the M98B in action with a straight pull bolt with 12x optics.

As always this has been supercolleydog COLONEL SERVICE STAR 16 giving you some information on the Battlefield 3 guns.