Know how to manage both crowds and ammo you may run out of ammo when you least expect it, leaving you defenseless against a very angry horde.
In contrast, assault rifles will not be able to hold their own against large ZEDs, forcing you to either gun them down with help or to run away and find a better position to fight in.
Most assault rifles have a decent magazine size of 30, and will increase even further with some skills. Assault rifles are powerful enough to handle weaker ZEDs with minimal effort, and medium ZEDs with only some effort.
