+1 on what Jim says. A 98k Bring-back, with no import marks, is EASILY worth $500 in decent condition. Depending on rarity, it could go three times that. The Russian capture guns with their mismatched, electropenciled bolts, cheezy red lacquer, and Russian arsenal reblue job fetch $250 - 350 at dealer cost.
if you want a Mauser to sporterize, buy a Turk or a 24/47 or M48 Yugo with zero collector interest.
You will come out ahead on money to start with a commercial action -- trust me. I love to convert the old girls, starting with actions that have already been bubba'd, but I don't do it to save money.
Clemson