You might have some plastic build up from the sabots. I don't shoot sabots, so I don't know what product to use to remove it.
Most of the members here use sabots. Someone will help you out.
You should find the JB at any gun shop, but you may not need it. See about the plastic first. Also, if you don't want to do the water thing. Any black powder solvent should get it clean. Your TC cleaning kit should be fine.