Might be that one, will have to check later when in game.
It does work on any current explosive round or device. My pretty large group always use it for Arkos runs and we always clean up.
I think it has to be, I'm not aware of any other perk that impacts blast radius. I will pick it up on my next level up and test. If so this build will get even better.
Of course, the risk for blowing yourself up increases as well. Lol. No risk, no reward!