I used to have one when I was a kid. Ordered it out of the back of Soldier of Fortune magazine. it came with a do-it-yourself dart making kit. You'd cut the rod to the length you wanted, then heat it up and plunge it into a plastic bead. We started experimenting with longer than recommended darts with multiple beads on the end. I remember being able to completely penetrate a piece of half inch plywood with those things. They are truly dangerous and very very accurate. you could easily wax an unsuspecting bird with it. Wish I still had it.
I remember making pretty dangerous projectiles out of a hair clip, rubber band, and straw... They wouldn't penetrate plywood very well, but they could stick a soft-barked tree pretty well at close range... their main problem was accuracy.
After the store closes (I work at Staples) and we've got nothing better to do, we take those mini sharpies and insert a rubber band into the clip. Those things are accurate, but not really painful, and a hell of a lot of fun.
Made several blowguns as kids, usually out of in-line straws, a needle and some thread. But, that got old after a while, ya know, using our lungs, so...
We bought a high power CO2 rifle and loaded our home made blow darts in that.
1/2", pffft. These suckers would go through 1/2" of plywood and about halfway into a 2x4. heh.