How does the transfer of items between the primary and the expedition save work?

So I am pretty sure I've reached the point in the The Swarm expedition where i can't progress further alone, and now the community has to work together on the prismatic core before we all can progress and all of that. But the main reason I started the expedition in the first place was because I wanted the sick armor set and Direwasp rifle multitool, but I don't know how to transfer the Direwasp multitool over to my primary save file. To be honest i don't actually know if it is possible, as I've asked around in-game and gotten conflicting answers. Some people have told me that I can transfer my Direwasp multitool over, and others have said that I have to wait until the end of the expedition. So I am simply asking for a concrete and correct answer; can I transfer my expedition loot, my new multitool and recipes over to my primary save file now, or do I have to wait until the end of the expedition?