An HP-CR will work with the HP-C needle/nozzle tip. But the HP-C will NOT work with the HP-CR needle/nozzle. Something in the thread of the nozzle will not let the HP-C nozzle thread on to the HP-CR nose. And the HP-CR just looks too weird and scary with an HP-C tip. The smaller, thinner, more tapered tip from the HP-C in the CR protrudes past the needle protector and can easily be bent.
Why would you want to make that strange combination? Just curious.