I've got loads of tracer info, albeit for modern ammo. From what I have, a single .50 caliber APT [armor piercing tracer] burns for between 1.4 and 1.8 seconds. As a reference, a 660 grain .50 BMG round will travel 3,080 feet in a single second. That distance is given for API ammo, not APT. Why? I have no idea, it's the way the reference page is printed.
Flakbait
A man standing in the shadows of giants