Alectoris,
TAC is one of the cleanest-burning powders around.
The only exception might be when somebody tried to use it in reduced loads. It's designed to be loaded right up around 60,000 psi. A lot of powders burn dirty when they're used at pressures lower than they're designed for.
Glad you liked the optics book. I'm going to publish a new, updated optics book next year.
