That, is a HVA action, a "smallring" and one of the nicer sporting bolt actions ever made, IMO. I have two fine custom light rifles on it and would have a few more built if I were 15-20 years younger....
A Micky Mauser WILL fit, just needs a good man with "plastic handles" to fit it and the most cost effective and very sound stock for this rifle would be a Bansner. I would send them the barreled action and have them do the work.
