Same family? Sure, just like 221 fb, 223 rem, etc. Those pundits that keep saying it's just a 222 mag, obviously are smarter than Dave Kiff at PTG.
I forget to mention the obvious to savgebolt....yes, it would need a new bbl to be 20 cal.
I changed another Axis 223 into a 6.5 TCU with a McGowan SS bbl. Yep same bolt face, etc. Why? I like to tinker and have a TC 14" in 6.5 TCU, so I had all the supplies.
The reason I did my 22-204 is I have a quantity of new 223 Axis bbls and a M12 in 204R, so I have brass, etc....

ron