Non-discrete weaponry such as heavy machine guns, assault rifles (fully automatic), installation/vehicle turret blasters should have a tracer round fired every so many shots but not all weoponry should get this ie. Sniper rifles.... fps games which had tracer rounds on sniper rifles were lame.

Also, player icons should not show up on everyone's hud just because they were detected by a team mate half way across the map or because you fired a shot. The exception being if you trained and equipped gear to transmit/receive this data to your squad mates or at higher levels to your platoon or entire team. Additionally allow for special equipment to detect long range sniper shots etc and sniper noise cancelling devices to counter measure this form of detection.

Edit - otherwise miniscule size ammunition should have virtually no visual detection at all. Purpose of this is to boost the realism and improve the tactical nature of these weopons.

See, that idea is pretty much synonymous with C3 in Battletech/MechWarrior. If you have it equipped you can transmit targeting data to everyone else in your unit, but it takes up tons that you could use for armor or ammunition. Just have such a system take up an Equipment slot in Dust.