100-1000 and up depending on specifics
No- the 7x57 was developed separately, in 1892 by Paul Mauser. The 8mm Mauser (actually the 7.92 Mauser, but every calls it the 8mm) was developed by a government board.
Numerous commercial and custom makers have made 8mm Mauser rifles in the last 100 years
$175 to $800 depending on condition and matching parts.
What about it?
No
The 8mm Mauser is a good black bear round. American 8mm is kind of underpowered but with handloading or European ammo its in the same class as 30-06..
Minor collector's interest- .50 to 1.50, depending on condition. There are some supplies of Nazi marked 8mm Mauser still turning up for sale.
$450
Yes....
10000.00
value depends on overall condition................
"No, 7.92 is German military caliber for WW 2 and earlier Mauser rifles." Actually, 7.92x57 is the same thing as the 8MM Mauser, if that's what the person was asking.