Working on guns is FUN! Changing things, upgrading, having something a little different is one of my favorite past times. BUT I promise you these endeavors done correctly by a gunsmithshould be more expensive than a brand new rifle. Its all in what you want. Myself, it sounds like you have a great gun, I would consider keeping it as is and buying a new one. If you do move forward with a re-chamber find out the cost of All work needed first, make a realistic assesment of what you will have when you finish.

Most of all do something you will enjoy.

One note, you can get a Mauser action cheap, and build a gun yourself with some study and a few tools.