I've been thinking about your question, while reflecting on my own history of purchasing. I kinda started with your objective but modified it thru experience.I ended up just buying more actions. I shot my new "used" Hall for the first time, yesterday. It came with a ppc boltface. It also came with a 30br barrel. The brass for the 30br had been rebated professionally to work with the ppc boltface. That could work for you for some possible options, but not cover the 223 boltface. Early on, I bought a vise and planned on switching barrels on one good action. That takes time. Besides switching the barrel and cleaning out the anti seize, you have to rezero your scope.I found I would rather use that time to reload and shoot. If your bolts are going to cost $400 each, I think you should buy 2 actions. For the 223, you could consider a t3 or an old 595 and rebarreled it. Mine shoots great. I think the only limiting factor with that gun is me. Just putting some thoughts out there for consideration.