Magazine type?
 

I have a wood bottom magazine with marking I haven't seen before. If you hold it with the rounded edge up and flat one down the S/N 2157 reads across the center of the bottom. Above the s/n is a stamp with SA in Helvetica font surrounded by a rectangle with slightly rounded corners. The spring is the round type and the wood appears to be walnut.

The "SA" inside a rectangle stamp is a Finnish acceptance stamp

"Suomi Armee"