[BallisticWookie]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>The 5.56-mm tracer, M856 (A064) cartridge has a 63.7 grain bullet without a steel penetrator. It is identified by an orange tip. The tracer is used for adjustments after observation, incendiary effects, and signalling. When tracer rounds are fired, they are mixed with ball ammunition in a ratio of four ball rounds to one tracer round. The DODAC for ball and tracer mix is A064.<HR></BLOCKQUOTE>

Taken from http://www.fas.org/man/dod-101/sys/land/556.htm
this is only for 5.56mm ammunition, I'm sure all tracer rounds are made the same way though, this is all I could find, not really in the mood for searching anymore, sorry