Thank you for the comment. I changed my code up a bit and switched over to using quats, but I’m still having the same issue of jittering while aiming near +75 or -75 pitch.
FQuat CurrentConeRotation = TestRotationCone->GetComponentQuat();
FQuat ConeRotationDelta = FirstPersonCameraComponent->GetComponentQuat() - CurrentConeRotation;
FQuat DesiredRelativeRotation = Mesh_Body->GetComponentTransform().InverseTransformRotation((TestRotationSceneComponent->GetComponentQuat() + ConeRotationDelta)).GetNormalized();
TestRotationSceneComponent->SetRelativeRotation(DesiredRelativeRotation);