The cotton swabs were cut in half making two darts, the ends were then carved to a slight point with a knife, to allow it to stick into the screw. The heat shrink I used is too long so it was cut in half and placed over both the two screws and the shafts. A heat gun was then used to shrink it together forming a strong bond.
The cotton will start to degrade after a few shots needing to be re-twisted back onto the shaft. After 8 or so shots per dart the cotton starts to effects accuracy. At this point the shaft can easily be removed by pulling it, whilst holding the heat shrink tubing with your nails. You can then insert a new shaft and keep shooting (once you've made your first darts there is no need to carve the ends of the shafts).
