Can someone give me a quick TL DR of the new Team reloading buff.

Returning to HD2 because I heard finally they looked into team reloading which is one of my favorites thing to do.

I know that you can now reload from the shooters backpack as well.

But I tried team reloading for someone without having the same backpack as them and it didnt work, which I thought you could. (Unless it was of course bugged)

So is that all or is there something that I dont know?