I believe your rifle was made for Western Auto by OF Mossberg as their Model 640K. Magazines can be ordered at most gun dealers. They are available from Havlin Sales for $27, or Numrich for $32.50, plus shipping.
The Model 107 was a single-shot shotgun, not a .22 Magnum rifle. Please send us all the markings directly copied from the rifle so we can properly identify it. We have magazines for virtually all Savage/Stevens products manufactured since 1900. sales@countrygunsmith.net
Revelation Model 107 was made by Mossberg (Model 640K)
Yes, they made that model
If has the magnum cylinder it will.
1976
Here is your answer: http://www.gundata.net/western_auto_revelation.html
the R-107 was made for .22 LR only I believe. the R-106 had dual cylinders for it. I would contact High Standard and find out. But from what I know, High Standard R-107 didn't come with a Magnum Cylinder.
Mossberg
Made in 1968.
20-150 USD or so
The Stevens model 107 shotgun was made from 1912-1945.stevens made 443,500 shotguns during this time frame.