This sounds like one of the Israel's And it could be built on any one of number of actions. They measure these by the distance between the stock bolt holes. I don't have the reference in front of me at the moment but there are short, intermediate and long. Then there is the receiver size, large ring and small ring. The large ring the threaded barrel shank is 1.10 inches the small ring is .986 12 tpi 55 degree thread usually though some 60 degree threads are some times encountered. And there are some large ring small barrel shank actions (usually Turkish) out there. Most pre 1898 (91, 92 ,93, 95, 96) actions are small ring cock on close actions. On 1898 and later actions there are both large and small ring actions and they cock on open. With this being said the estimates are that some where over 20 million mauser where built before the end of WWII by numerous arsenals there for the above statements are what is usual found in the surplus Mauser world but by no means are these hard fast rules. You may encounter some really odd versions in the Mauser family depending on who and where they where made.