Calibre .223 Rem. (5,56 × 45 mm) is standard for the semi-autos of the CR223 class and is used for sport and sometimes also used for hunting. The rapid shooting of this rifle category however quickly causes shooting and training of specific sporting disciplines to become highly cost intensive. C.G. Haenel reacted to this issue by developing a conversion kit in cooperation with the US-American accessory specialist CMMG. Using the new small calibre conversion kit allows CR223 owners to use the calibre .22 LR.

Converting the rifle works quickly, tool-less and uncomplicated. No permanent changes to the system have to be carried out and converting it back to original is done in the same way. To buy the conversion kit, the legal limitations of the respective countries apply.