Wouldn't a bore guide for a CZ 452/455 work on your Brno model 4 ? Sinclair/Brownells offers Delrin guides for the CZ rifles, it's generally suggested that you use a 17 caliber guide and rod combination with a 22 caliber rod end adapter on the CZ rifles to keep the cleaning rod from dragging on the actions ejector that's a part of the magazine well. Other guide rods are offered by MWerks, Possom Hollow (the same guide as Sinclair) and Mike Lucas. But they tend to cost more,
