So I updated the rifled barrel for Nerf darts from 4 lines to 6 lines. Designed to work with short darts. Tested with worker gen 3 and ACC gen 3. Has the benefit of not needing to tie fishing lines.
However, you need a 29 mm length of 9/16 inch brass from K&S to put at the top. The idea is to reduce the extent which some stray darts will fly out. So the darts will accelerate in the barrel, spin in the rifling then stabilise in the 9/16 brass.
The 3 models are named for the outer diameter of the barrel which they will be used for. 16 means for 16 mm barrels. 58 means for 5/8 inch barrels like the caliburn. 1732 means for 17/32 inch brass from K&S.
JSS stands for Just Shoot Straight, just in case you are wondering.