Same with my CZ-452 American. Bore is too small to use a regular .22 cleaning rod. I also use a .17 sized cleaning rod & .22 caliber bore snake.CZ for sure. Only caveat, at least with my 2 .22 CZs, is the bore is so tight I have to use a .17 cal. cleaning rod. The .22 cleaning rods I have won't go through the barrel.