I have no insights of the m/29 gas cartridge, my notes are only of the erlier m/25 but might give a bit of a aspect around the use.
The m/25 were intended for training, to be used with a signal pistol (Probably m/18). The cartridge were used indoor in a gas chamber to create gas for training and testing of gas masks. The cartridge were not to be used outdoor. The regiments could place a requisition for 10-50 rounds on a yearly basis. Each regiments had different alowences pre-set.
EOD, the bunter of the cartridge looks strange indeed. I have no knowledge of the Nordfelt cases or bunters, and the second cartridge I have seen were with the year of 1899 Marieberg. I might be totally wrong, but the look of things is that there is a say 8x58RD case fused with a Nordfelt cartridge. I have asked Texz to take a closer look on the cartridge when he has it in his hands.