I have been down the "re-barrel the military Mauser" road several times. I will offer you some of my experiences.
I bought a J C Higgens 30-06 rifle, which had a made in Belgium commercial Mauser action. It looked just like the action on my Belgium Browning Safari rifle. I had all the work done and was loading Barnes Bullets for this new custom 35 Whelen. There is a magic sweet spot with COL for Barnes Bullet. I found it, and it was about a weak 1/8" too long for the magazine. The magazine on this rifle was about 3/16" shorter than my Safari. The bolt was the same length but the magazine was a critical "tad" shorter.
Making the loaded ammo fit the magazine the accuracy was awful.
I sold it.
The 1909 Argentine Mauser is considered an excellent Mauser for custom rifles. There was never a bunch built in a hurry as with German 98's produced when Germany was losing the war.
I had a sweet 7x57 built, with a syntethic stock. The trigger was smooth but heavy. I asked my gunsmith to lighten it up. He was getting old and tired then. In years past he loved tuning up military triggers which is an art.
He slipped in a boxed Timney trigger. During those years I was having many hunts deep in the desert for Los Burros, mule deer. They were great wilderness adventures. One day coming back to camp I was in a desert sand storm. So much fine powdered sand blowing in whirls.
I protected my rifle as best I could. The next day I dry fired it and just enough fine sand got trapped in the boxed trigger, the pull went way up. At home it measured almost 9 pounds up from a clean four with the original Mauser trigger. They are self cleaning mostly, but if needed take the stock off and clean it with a dry toothbrush. I tried getting the original trigger back, but my gunsmith got old and lost his mind.
I sold it.