More powerful (louder) "bird bombs"?

OK guys, I'm new to rec.pyrotechnics and have a question for you all.

How do I make louder wildlife control shells for my 37mm flare
launcher?

The obvious answer would be to add a larger quantity of gunpowder to
the shell, but I can't do that. I must keep the total mass of
explosive less than 7 grams without violating BATFE regulations
(illegal manufacture of a destructive device).

I have been using blackpowder. Is there something else I can use that
will be significantly louder?

Is there a good combination of chemicals I can mix together to achieve
this?

I guess I should add one caveot.... I want this to be SAFE!

So no unstable mixtures like using flash powder or similar.

Thanks.