This tutorial is actually more about animations than it is for the feature in the title, to add a weapon inspect ability, just add this blueprint to the character and set your montage to play.
What I actually wanted to show is how to use TPS animations for FPS arms. It’s not hard, just duplicate the animation and set the arms skeleton, where things get hard to put into words is when you need to add keyframes and make modification to the new animation, so in this video I do few such modifications to show you how you can make use of TPS animations for FPS arms, you can spent more time tweaking the keyframes as you see fit and make it much more detailed.
With this approach you can make use of quite a lot of animations https://www.unrealengine.com/marketplace/en-US/content-cat/assets/animations
FPS Game Starter Kit 