I have the opportunity to get a slightly (cut barrel, bent bolt handle) sporterized 1891 Argentine Mauser in good shape. What could I do with this as far as modifications go? The original 7.65 Argentine round would be nice but if the barrel is shot what are my other caliber options. I know I am pretty much limited by the box magazine and would not want to get into a major modification. These are petty little actions but do not seem to lend themselves to much versatility in customizations.