Video: YouTuber Giaco Whatever is on a quest to build a Nerf blaster that will do more than just leave a tiny welt on someone. He's constructed an air-powered dart cannon that generates 400 PSI of pressure, and when cranked to full power, it can apparently send a Nerf dart flying at Mach 2.3, twice the speed of sound, or around 2840km/h.
Video. One of the things that makes toy dart blasters fun is that they can't really hurt you. Sure, it doesn't exactly tickle if you get shot at close range, but toy makers limit the power to keep lawsuits at bay. However, you don't ever want to find yourselves in the crosshairs of this homebrew dart gun that's powerful enough to pierce a can.
On impact with a hard surface like a wooden board, the dart disintegrates into scraps of foam shrapnel. Replace that board with a person, and it's going to do a lot worse than just leaving a massive bruise. Given the size of the dart's soft tip, and the light weight of the foam, it might not break the skin, but that's why Giaco Whatever is already working on a second version of this cannon. Please, keep it away from us.