100-10000 usd
Gunsmith
Numerous commercial and custom makers have made 8mm Mauser rifles in the last 100 years
it is actually a mauser rifle. the mauser action is one of the most popular and strongest out there even today. most "shooters" will cost around 100.00 to 150.00 depending on your area. they are popular with the custom guys so they can build a custom rifle around the action.
100-500 USD
It will be marked on the barrel/reciever
Any of the major barrel makers should be able to help you - Lija, McMillan, etc..
I have one and it is a 7x57 caliber is stamped on the left side of the barrel.
50-500 usd
Depends on who did it, how long ago it was done, quality of the work, etc..
Depending on who did the conversion; 100-500 USD
Can't be answered without a detailed description of ALL markings, condition, history, accessories, etc..
Not Much If you have a second Year 1938 .But you have a Mauser action on it.That means the barrel is not Winchester. How did you decide that it is a 1938. the only way forsure to know is the Ser.No. on the gun .If it is a Mauser action. It would not have the correct Ser.No. i have a model 70 serial # 2760 its a 1937- the bolt # should match the barrel# pull the bolt back and look carefully on the bottom and you can see the bolt #