Real-World Background: It's easy to see that, whatever the perfect machine-gun is, the WW2-era MG42 was pretty close to it (if not for fear factor alone). Bullets would tear through Allied formations, the gun bringing full-size 7.92x57 cartridges to over 1200 rpm, sounding as though a a giant piece of canvas were being torn as it fired. Along with so many other German technologies, the MG42's design lives on to this very day, with the MG3 being patterned after the gun almost in its entirety. Though made with modern processes, the MG3 echoes the same rate of fire, the same internals, the same fearsome full caliber. The gun is denominated as a GPMG, being able to fit the same roles as its predecessor, along with the added benefit of lighter materials. Quite frankly, a gun such as this speaks to a time of war geared towards power, yet altered for its current situation so it is geared towards precision.

Notes for Usage: The MG3 has an utterly massive rate of fire, but this can also be its prime weakness - you're going to be ripping through ammo in mere seconds. The MG3 has very distinctive iron sights, and they are unlike anything else in the game. Players who have experienced World War II shooters with the MG42 present should be instantly familiar, but they are not ideal in-game. Some of the LMGs you will have unlocked before the MG3 has been unlocked have 200 rounds in a belt - the MG3 is not one of these weapons, and has a 100 round belt. Remember this when firing the MG3, and remember also that burst firing is futile - a 'burst' with the MG3 translates to eight or more rounds, so it's more effective to keep pumping lead until the target ceases to exist.

Optics: The iron sights won't be very useful if you have to fire out to distance, so an RDS is recommended for most situations. ACOG isn't particularly useful with the MG3 as the rate of fire makes the reticle jump more than manageable. 

Prime Environment: Urban (Example: Base 2 on Islas Inocentes)