thank you bakposten, that explain a lot

every known rifle till now have the serial number here

I will go into the facts about the Geco/ Kaba Mauser we know till now:
lowest number 905 proofed 5 1929 engraving and a least front sight design is different from later rifles
highest number with this features is 986

between 986 and 1146, proof 5 1931, there were a change. maybe because geco change the gunmaker or only the engraver and the barrel maker in Suhl/Zella Mehlis. maybe another unknown reason!
1159 is than the last rifle in 10,75x57 we have.

1197 and 1206 and also the reworked 1207 are in 9,3x57 and I have no doubt the rifles between will be chambered for the 9,3. maybe this was the first lot of the geco/kaba mauser for the swedish cartridge and it must be made around 1931.

1273 is still in 10,75x57

1347 in 10,75x57 proof 6 1931

and than there is a hooooooole

bakpostens rifle number 3511 proof 6 1932 but the serial number is not like on the other rifles

2200 rifles made in only one year but invincible! did they found one or more rifles in the white or parts for complete rifles in 1932, number and proof them. because its a geco/kaba serial number maybe the 2200 missing links were cheap rimfire rifles made by some else for geco and having this missing numbers.

the years 1931/32 were not the best, for nobody
it was the Great Depression

I am searching information about the 10,75x57 cartridge fror years and the Geco Kaba Mauser is the only known modell make in "masses" for this round. because of its shotgun style trigger guard its distinctive. I have only heard of one M 88 sporter and till now 4 Mannlicher Schönauer M 1912.

any information will be welcome