What does the Forward Assist on the AR15 Do?

AR-15 Cleaning Kit - https://amzn.to/2wHbrY0
Rifle Bipod - https://amzn.to/2UQVmqE
Red Dot Sight - https://amzn.to/3avH0m0
AR-15 Cleaning Mat - https://amzn.to/2xFMGLz
AR-15 Rail Covers - https://amzn.to/2QZ0qbg
https://amzn.to/3B0oFLX

In this video I demonstrate why the AR15/M16 platforms have a Forward Assist, and how it works. My rifle is the Dominion Arms 556.