The MG3 performs like it's peers, however it boasts extremely high damage and has a very good firing rate. Like most of the weapons in it's class, it has 50 rounds in the magazine. The downside is that it has extremely high recoil, possibly the highest out of all the light machine guns, meaning that hitting targets at long range is extremely difficult. In RCF the popularity dropped down a little due to its nerfed recoil, range, and accuracy. Some say it's the worst support in the tier tree unlocks.
Overall it's recommended for close quarter combat,since its practically impossible to hit targets at medium ranges,let alone on long range with full auto.