The RCBS ones aren't built like the Lee ones. RCBS doesn't have a slip-collar for the decapping pin. Just a threaded rod into the top of the die which is locked in place by another nut from the top. The decapping pin is a replaceable doo-dad that screws off the tip. Everything is hard-locked in place when running, with no give.
The power-punch decapper I got is supposed to have some give to it, but I'm not sure if that will end up being a good thing or not...