Here’s how you balance an Assault Rifle for TF2:
See this lad here?
Give it a 3 ROUND BURST only with no bonus headshot damage.
A Secondary for Heavy, Soldier, or Pyro who want a little more range than what the Shotgun could provide at the cost of fire rate being slower between bursts.
Engineer, at least in my eyes, is a Shotgun kind of Guy who wouldn’t be into Rifles.