I’m glad you achieved what you wanted, but I don’t get something.
4. How can you get a forward vector of the rotation? Rotation itself is already a vector. You can get Forward Vector of an actor. Find Look At Rotation already returns you the direction from your gun barrel to the impact point.
5. If you add three vectors, the result will not be correct. When you get the vector from the Find Look At Rotation node, you only have to add it to the Gun Barrel location, not the Camera location. (Edtd: Unless the Gun is a child to the Camera and you add the Gun’s relative location; in that case the result would be correct; but instead you can get the Gun’s world location and leave the Camera be)
Just a little trick to do to check if it’s right: select everything in the level and move it alond the axes by a few thousand units. I think the default level is somewhere around 0,0,0 in the world coordinates, and maybe if anything with the vectors is not right, you won’t see a great difference. But if your character’s location is somthing like 7648,2345,990, the error of adding more vectors that you should will be quite visible.