They are not op, they are balanced. However they are a good well rounded weapon making them easy to use out of a person's element, an expert hand cannon user will pick up an auto rifle and be decent. An auto rifle user will pick up a hand cannon and have a hard time (not the case for everyone) this is what auto rifles are best at, a well rounded weapon that anyone can grab and be decent. If you are having a hard time beating them you either need to practice with your weapon of choice or pick a weapon that is more suited to your play style.