More than half the fun of owning and shooting a blowgun, for me, is designing and making the darts!
My favorite dart has been the wire dart that I make in two lenghts, 5.25" long (2.5 grams) and 6.75" long (3.25 grams) but my (drinking) straw darts are fast becoming my favorite dart at about 9.5" to 10.0" long weighing about 4.5 grams. These straw darts shoot about the same as the lighter wire darts I make but hit much harder because of their increased weight. The nail tip is a 6 penny nail that can also be hammered (forged) flat into a nice blade shape that can be shapened with a barb filed in as well (not shown above).
The reason I suspect I observe this difference of the heavier straw darts shooting the same or even slightly better then my lighter wire darts is the "rocket" effect provided of these long hollow drinking straws shafts. The cone seals the tube to allow the breath pressure behind the dart to build and push it down the tube as usual but the difference is this pressure also enters the straw shaft and is available as the cone leaves the barrel thus providing a bit more "thrust". I'd be interested in other people's comments on this alledged "rocket" effect.