I would try to find a post-WWII FN commercial action, like the ones used on the old Sears J.C. Higgins rifles. These already have a side safety, low bolt handle, and are drilled and tapped for a scope mount base. In addition, they are stronger due to lack of the thumb cutout in the receiver wall, and don't have questionable heat-treatment like so many military Mausers.

Another great choice would be the Venezuelan M1924 FN action if in pristine condition.