The darts I make are either wire or bamboo. The wire has a good weight and hits well but they bend out of shape very easily. The bamboo is much tougher but is very light, with little penetration (great for paper).
The "cones" are foam. The yellow ones is craft foam, it's fairly dense. The grey stuff is pretty spongy but works well. I cut them out by sharpening a short lenth of 1/2" EMT, if I had a 1/2" punch I would use it. I've tried punching the center hole but I don't have a small enough punch and when I try the hole gets way off center sometimes, it's easier for me to just push the shaft though. On the darts with the yellow foam, you can see duct tape on the wire to hold the foam in place and to keep them spaced apart.
The yellow foam is spaced out and the grey foam is longer than your average cone dart so that it helps keep the shaft true to the barrel(sometimes with cones, you can hear the shaft hitting the inside of the barrel when loaded).
I've learned that water can actually be used to saturate the foam for both lubrication and to add sealing power. Instead of sharpening the wire darts, I make the cuts at angles to make a nice point.
When you make darts, try to make them all alike. The more consistant the dart the more consistant you can shoot.
