Thanks for all the great info, the work is what I am most looking forward to do. People say they have build customs but they have brokered a custom I am a retired prototype machinist as well as a nuclear industry tig welder. I look forward to the chalenge of the complete package from stock inletting to metal finishing, Again thanks
Part of the fun, is selecting an action that is suitable.
98 Mauser actions, especially large ring models will pretty much interchange all of their parts with few if any problems. I have checked hundreds, if not thousands of 98s for headspace. I have only seen a few with issues, less than ten. In every case, it was because of set back on the receiver lug seats. All of the actions, except one had been commercially sporterized in Europe. None of those were in their original chambering.
The one milsurp that had set back was an early wartime production Mauserwerke. It was soft all through. Somehow it had slipped through all of the inspectors. There wasn't even a Brinnell mark on the recoil lug. The original inspection stamps were there otherwise. Alan Lever, said to cut it in half with a torch, after stripping it of useable parts of course.
Be very careful when you choose a receiver. All of the parts may interchange but, depending on who made them, they might need a bit of tweeking. The rear receiver bridge is something to look very closely at. If it is roughly finished and has deep machining marks, pass on it. There is a very good chance it won't clean up and still keep within the dimensions neccessary to get available scope bases to fit properly.
The Brazilian, Mauser made, 1908 Mausers on sale right now at P&S Guns and Militaria, as well as the Steyr made Model 1912s are excellent candidates for your purposes.
TEC, one of the banner advertizers has these as well. Go for the 7x57 chambered rifles though. They're mismatched which won't matter to you and they don't have a big ugly 7.62 Nato stamp on the rear receiver bridge.