Your assurance of perfect alignment. The jaws actually float to permit the cartridge to find its exact center in the die.
When a case is in the shell holder, it’s supported by spring-loaded jaws that contact the base of the cannelure for more positive extraction. The shell holder is also self acting, so when a cartridge is placed in the die and the handle of the Co-Ax Press is activated, the jaws can open and close on the cartridge case. When the handle is raised, the jaws automatically open and release the case.
