diameter of mini broadheads/razor heads metal shaft is 2.5mm. Don't know bamboo. Using stainless steel capillary tube OD 3mm ID 2.5mm you can mount metal heads from razor darts on the 2.5mm carbon shafts that fit the cones. Resulting darts surpass all else I've tried, you can make any weight or length you want. Tim Wells rat darts are also 2.5mm and compatible with this systemDoes anyone know the exact diameter of the .625 Cold Steel bamboo shafts?
Looks like 4mm to me. I want to use the cones with carbon fiber rods.
hope this helps!