Your question leaves many spots open. Biggest question is "why". Do you have a chassis that is for LA mag, or can get one with substantial discount (compared to SA chassis)?
With the info given, there will be one culprit. You need to change or modify the bolt stop, so that bolt will go further back to pick up cartridges.
Other thing is, all LA AICS mags are not compatible with Tikka. MDT site seems to be down, but you can check there later. They specify certain shorter OAL mag that works with Tikka LA.