As I understand it, all Tikkas are built on the same long action. As for the chassis, I believe the difference is just the length the magwell is cut for. So in the case of the .223, its the short. I'd reach out to Seekins to be sure before ordering thoughNot sure if you mentioned it prior, but seeing that seekins is offering in two length actions, regardless of tikka sizes, did you get the short action or long action? Curious if the long will still feed .223 well