The mighty .338 Lapua Mag. This is how I would balance the sniper rifles in a shooter. All of the battle rifles could easily be built to be DMR, but they would never have the lethality of a true sniper rifle. The idea here is to take out the run and gun sniper stuff we see. They basically have a one shot kill gun but they use it like an assault rifle. By making the gun virtually useless on the move (or while in any position other than prone really), that problem is solved. On the flip side of the coin, the gun is very useful when used properly - prone gives the player perfect stability since the bi-pod will be deployed and kneeling is better than standing). Essentially there would be so much movement while using the gun standing, and even more while moving, AND finding the target again after taking a shot would take far too long to be useful; that no one would be successful using it for run and gun.
Something that always baffles me is when video game designers somehow conclude that the .308 sniper rifle they put in the game is more powerful than the .308 battle rifle they have also included in the game or that they magically hold fewer rounds than they should in order to balance out the score card. Then of course we have the .50 cal rifles that mysteriously don't do the kind of damage that they actually do. They apparently believe that a person would actually be able to continue fighting after being hit by a SEVEN HUNDRED grain projectile. Or that body armor actually protects from .50BMG. Same goes for .338LM. There is no surviving a hit from these guns in Gunfighter. The best a player can hope for is to hit the ground and need to be rescued by a team mate. There is a much greater probability that if you are hit in the upper torso you're a dead man, and of course head shots are instant death.
I would also have an "accessory" for the snipers, available only for the Sniper scope which figures bullet drop and illuminates the proper place on the reticule.