Tracer Round Ballistic Coefficient

[photog_shooter]

Is there any way to determine the ballistic coefficient of a tracer bullet? I have some 308 tracer rounds, they seem to weigh in around the 144 gr mark. All of those wonderful ballistic calculators ask for a ballistic coefficient. Of course, if these were some off the shelf bullet then I'd be able to go onto the manufacturers site and find the info. Unfortunately though, it's a bit harder to do with pulled tracer rounds.

 

[Rookie{OMC}]

The problem of them getting lighter the farther they go,would be the challenge I think.