Overview
HK21 is an MG whose Skill grants herself additional Ammo and increases her own Damage with a long ICD.
MGs in general have several major issues that cause them to be ineffective for general content in comparison to ARs and RFs. They spend large amounts of time reloading, they have low Accuracy and their targeting is random. Add in the fact that their supposed niche in “burst damage” only applies for the first few seconds of a fight, and a good RF or AR will outperform them shortly after Skills come into play, long before the fight is over. HK21 does not alleviate any of these issues and as such, is not recommended for general use.