The converted 98 Mausers, usually marked Remo or Ghia, are an interesting piece of work.
While the converted actions have plenty of locking strength (for shotgun shell pressures) the action has a glaring safety problem - the separate bolt head is held on by spring pressure only and it can be knocked off while the bolt is being worked. There is the potential that a round can be fired without the bolt head in place! The American Rifleman magazine years ago mentioned that accidents had occurred that were caused by this design flaw. Here's how they happen: First shot - <Bang>, no problem, cycle bolt quickly, bolt head pops off at the back of the bolt stroke, shooter does not notice, closes bolt (yes, the firing pin will push a shell out of the magazine into the chamber, even without a bolt head) and <Boom>, bad things happen.
Another point of weakness on these old guns is the stock, generally wood was removed from the inside of the action in order to accommodate the bigger shotgun shells and this, along with the recoil of heavy shotshells, can result in cracked stocks.
I have a couple of these old beasts (12 & 16 Ga) and I do shoot them on rare occasions, but I am careful to check that the bolt head is in place every time I chamber a shell. If you can't remember to do that every time, better to shoot something else instead.
As to value I would say $75 to $120 depending on condition.
