excessive headspace

[Jack]

Mike Moss' method would be the cheapest, assuming you handload.
You could have the barrel set back to fix the headspace. Or, possibly, a different bolt would correct the problem.
You'll need to consult a gunsmith to find out.
One factor to think about is, how much money do you wanna sink into a Mauser 95? They're decent rifles, but you'll never make a first rate custom rifle from a 95 action, so, you're probably best off doing minimum modifications.
For that reason, I would not consider rechambering or rebarreling, if it were my rifle.