How is the FP Aiming down sights of Pubg made?

it looks like theres an animation that holds the weapon that the sight is right in the center. I really want to implement that in my project but i dont know how to realize that, if someone has ideas, i would really appreciate that.

FP aim down sight Pubg: (you can see it at the beginning )

The most flexible way is to setup a FVector / FRotator as Property per Item and then use this adjustment either applied on the mesh in code or using a skeletal controller in the anim graph, the biggest advantage is you can change Poses on the fly, for smoothness either do a FInterpTo or a custom algorithm. I have also done the way where you would author animations but in my oppinion it just makes asset management more difficult.

Does it takes much Performance?