I just completed this lecture and when I played, it didn’t seem like the gun was moving (although the AI character did follow me every single frame) so after a little digging and adding a print string to the end of Set Aim Animation in my Animation Blueprint, I realised the values never changed enough to really make a difference.
For example, even running up the spiral stairs and jumping, the new Pitch didn’t go higher than 17.
To overcome this, I changed the rotation values in the AimOffset blueprint from -45 to +45 which made the problem much better.