The bolt-action device can hold up to four pens. Credit: YouTube Get the Popular Science daily newsletter💡 Breakthroughs, discoveries, and DIY tips sent six days a week. The PVC pipe potato gun is a staple of many science-oriented (and frequently unsupervised) childhoods. There are plenty of variations to that starchy shooter, but the basic elements are invariably the same: load a potato inside the pipe barrel, fill the rear chamber with either combustible gas or compressed air, then fire away. In theory, you can launch any similarly sized object using the contraption.Why not swap the potato for something that can save lives? That’s what YouTuber Emily the Engineer pondered during a recent video entry . I Built an EpiPen Launcher “The only thing that modern medicine has lacked in is a more efficient way to distribute this medicine. Do you see where we’re going with this now?” she asks her viewers. Her final result is the EpiPen Launcher, a custom-built device that lives up to its name.…