Today the only blowguns I can think of being sold commercially are the ones from Cold Steel. I'll admit, I've really been impressed with Tim Wells and the things he kills with the blowgun (like a big male baboon.) I notice they have two sizes: One is .357 diameter, and the big one they brag about is .625 caliber. The bigger one is the one that has all of the broadhead darts available, along with several other kinds. That is, I think, the one Tim Wells uses. Correct me if I'm wrong, but shouldn't the smaller one be more powerful? It's not like a gun, where you want a bigger diameter bullet to make a bigger hole, even the biggest broadhead dart they make would fit inside the .357 tube. Since the velocity of my breath is what makes it go, it seems like the .357 one would develop more velocity, because my breath fills the larger blowgun with the same amount but the smaller tube would push the dart out faster. Am I missing something?