Without seeing project, my guess is that this is an ownership problem. Since Run On Server RPCs can only be called by Client on an actor owned by Client (such as player’s Character BP), weapon’s ownership might be set differently in a dedicated server scenario than it is in a listen server scenario and that’s probably why it isn’t firing on Server. Again, it’s just a guess, but you should be able to avoid this issue entirely by running your RoS RPCs in Character, Controller, or Player State BPs (as appropriate for situation).