In what way for directing fire or damage? Because a tracer should do as much damage as a ball round except with the possibility of catching dry materials on fire.
As for directing fire every 5th round in a belt of machine gun ammo is supposed to be a tracer. The draw back to tracers is people can see where you are shooting from as well.
The 231 uses straight tracers as that is the only way to direct fire for it when its in the firing port. It's really cool to remove from the vehicle and use with beta C mags
Brother in Arms