Hello from England. Interesting post... great idea to use disposable otoscope cones GIWTRO.
Apologies for the metric measurements in advance.
Heavy Weight Darts
My favourite heavy darts would have to be 75mm x 3.5mm steel nail darts with paper cone wrapped in and heavy duty duct tape for extra strength. I usually file these to a nice sharp point on a grinding stone with the tape taking up probably about 70% of the dart. These darts are great for showing off to your mates because they have the most powerful sounding thud when they hit something at full speed. 'Try getting that out' I usually say. They also don't bend as you prise them out of your target.
I have only ever made wire darts from bicycle spokes. They tend to be pretty straight and keep their sharp point very well. They do not however have a great deal of springiness to them so when pulling them out of the target they can often bend if you are not careful. Personally these darts are a little too spindly for me although they do fly pretty damn quick. As seen in my DP I use cork cones from bottles of wine (red wine of course) with a rubber washer glued to the backs to create a really snug fit. There is something very satisfying about loading these.
The lightest darts I have made so far are ones I am currently working on. These are made using 10mm x 3mm carbon extruded tubes, modified pointed razor blades and 15mm diameter polystyrene half cones wrapped in small magpie wing feathers for cones. Anyone who has ever held a piece of carbon tube this fine will tell you just how light this stuff really is. It weighs so little that you can't even really notice it just the feel of it on your skin.
The razor blades are the closest blades I can find to traditional arrow broad heads. I have modified them by snapping part of the bottom off so that they are more symmetrical and balanced in flight. I have then cut a groove down the carbon shafts (very carefully as my saw blades are 1/3 of the diameter of the tube) These have been glued in using two part epoxy. The polystyrene cones and feathers I have only ordered today but I hoping they will be easy enough to secure with tiny TINY elastic bands and some more two part epoxy glue. So far so good though!
The only stunner darts I have used are exactly the same as the heavy darts described above but with the nail head at the front. Very impressive to watch especially blasting them at cans!