Also can someone tell me why rebluing an old Mauser would hurt the value? Does this not further preserve the rifle for future generations?
While refinishing (of any kind) does preserve the rifle, what collectors are interested in, and paying for is the original, unaltered
condition of the rifle. Complete with all the dings, scrapes and bare spots the rifle has aquired during its service life.
Reblued, repaired or altered, unless done by the maker/user nation's arsenals, during the time of service, lowers its collector value. Collectors like nice, pristine working examples, BUT, a rusted battlefield pick up gun is worth more to them than a cleaned up reblued, restocked gun, or any sporterized modified rifle. Its about the history of the piece, first, and its function second.
You, I, and a lot of others see a gun with historical signifigance. Collectors see a historical artifact, that happens to be a gun. And they pay for that diffference, sometimes handsomely.
That $15 military surplus rifle in 1957, built into a beautiful sporter in the early 60s worth $3-400, AND it was a better rifle for hunting use.
Today, that same sporterized gun, is still worth $3-400 (or less, depending on the job done, and the local market), but an original unalterd issue condition gun can be worth 2-3x that to a collector. Really badly beat up GI issue condition guns are going for $7-900 or more, depending on the scarcity of the model, simply because there are so few left in original GI issue condition.