11mm Pin fire
9x20 or 9mm Browning long was used for Pistol m/07 and submachine gun m/37. The cartridge was created by Browning for their new pistol Browning m/03. The pistol was made under license by Husquarna as Pistol m/07, and there is where the ammunition is mainly used. The submachine gun m/37 where only used for a couple of years, before it was outdated and changed for 9x19 models instead. The 9x20 cartridge is a bit weaker than the 9x19 ammunition, but it is no bigger difference.
The cartridge is found in four generations in the Swedish defense:
First we used ammunition made in Belgium, by FN. This was for the first couple of years, before
the production could start in Sweden.
Then we started out the manufacturing ourselves in Sweden after the almost the same spec as the FN made round. I’m not sure, but I’m convinced that the cartridge differs in powder and primer. One other difference of course, is the head stamps. The oldest cases I have found with Swedish head stamps is from 1910.
There were extensive attempts during the 40th to gain better precision of the m/07 gun through changes of the bore of the gun and change the bullets form and diameter. A change of the bore gave to big stress to the weapon, where upon a change to the projectile was done instead. Ammunition manufactured after 1947 has much better precision than older ammunition. The testing showed that the bores dimensions in comparison to the projectiles diameter are of great importance. The best results in precision is not with brand new barrels, but with used barrels were the bore diameter is increased with 0,01-0,02 mm.
In the 60th or 70th (I don't know yet), finally, there was a change in the setup to use non corrosive primers. The boxes are easily recognized as modern.
The pistol m/07 and ammunition became obsolete 1996, after almost 90 years in service.
The ammo boxes may be found in many forms and labels. The only thing in common is that they are packed for 28 rounds in 4 rows. 4x7 rounds makes 4 filled magazines for the m/07 pistol.