T-N.T. APS-X inner barrel and hop rubber kits for the KJ KC-02 are proving to be very popular.
Specially designed grooves in the barrel create an air cushion that guide the bb eliminating contact with the barrel's sides. The air cushion is also dispersed out of the barrel ahead of the BB.
As the BB is untouched by the usual air bubble on exit, there is a lot less deviation usually created by it.
This version for the KJ KC-02 has a specific hop rubber for optimun performance.