This has been tried before. Mausers require the barrel to impact both the inner and outer locking shoulder. Just the way they were designed. If you do not bear against the inner locking shoulder, your groups will wander as the barrel heats up. The wander is about 4 moa from my experience.
I am not a big fan of Rhineland, they tend to oversimplify. Also, look at the "collar" and compare it to a Savage. It's only about half the width, and I am doubtful that it would stay locked.
Mr Death, you can use my pull through reamer, action wrench and barrel vise for as long you like. Those are the right tools for this job, and will work like a charm on that M48 of yours.