TPS Shooter with ADS aiming

Hey Devs,

So I’m trying to implement an FPS-like ADS system while aiming for my third person shooter game. I’ve see something like this in Fortnite and Off The Grid (see below).
My question is, how is such a mechanic implemented? From the looks of it, it looks like they switch from a TPS to FPS mode where they add a second camera attached to the head and add the skeletal mesh arms for the FPS reload animations…