I would restore such a rare rifle, even if it required a new copy barrel.I believe the barrelmaker in Germany, Lothar Walther can make a 100% exact copy of the A-Mauser contour. If I recall correct the contour is called "E" type which is a classic stepdown barrel used on these A-Mausers

I had a .333Jeffery made up some years ago( I still have it), and there are considerable x-tra actionwork to make it feed right, that it will destroy any chance to ever get it back to shoot 9.3mmMauser. These A-Mausers in 9,3mm are very very rare, that they do represent a collector value in almost any condition. We have here on this forum a member from the Lone-star state, that has Osa Johnsons A-mauser in 9,3mm. Just surf the pages.

As far as recoil, the 9,3mm and the .333Jeffery are identical, and ofcouse the bulletsellection is by the mile bigger in 9,3mm`s....but on the other hand, how many bullets does one need? I am pretty happy that I am stucked with Woodleigh 300 grains. After all, there was a reason why I wanted the triple-three Jeffery in the first place..I simply fell in love with these loooong bullets. I have seen how they perform on game in Africa