Yes, so he explained. The Qunari have cannon, but to my knowledge, even they have never learned how to make a cannon so small it can be held in the hand. And they are the only ones who know the secret to making explosive powder that uses no magic or lyrium. It is a secret they guard most closely.

(ooc: Kindly ignore the bit where Fenris temporarily forgot the Qunari have cannons in his conversation with Garrus about it. He wasn't really in his best state of mind at the time. >_> Or at least, that's my excuse . . .)