If this rifle is of Lowe or Mauser manufacture then heat treating should not be an issue but if this is an Ovideo manufactured rifle then the heat treating is a crap shoot. Spanish made Mauser rifles are know for some of them to have improper case hardening which shows up as bolt lug setback. This can be found by visual examination with the barrel removed. If there is a problem you will see indentations starting in the locking lug surface. If this is found there is no recourse for salvaging the receiver. If this is found then the more you shoot it the worse the condition becomes to the point that the bolt will have to be hammered open.

Obviously a Mauser type 98 action would be a better start. You might be able to find a Czech Vz24 for as little as $250 if the stock and barrel are not to good and you buy it for the action only. Another alternative would be to look for a Turkish K'Kale marked Mauser. The K'Kale marked actions and rifles where indigenously manufactured in a factory in Kirikale, on the outskirts of Ankara, in a factory set up for the Turks by the Czechoslovakians and, in my opinion, are every bit as good as the Czech and German actions.

Vlad