I would like some feedback on this does gi bore really get rid of rust on a firearm and has anyone use it for that purpose

The only thing that will get rid of rust is elbow grease.

To stop rust you have to remove the material that is rusting. Otherwise it will just come back.
GI cleaner will help remove rust, and will assist in keeping it at bay, but you gotta scrub to kill rust.

If you want to really kill it, you'll need to either sand blast, or bead blast, then refinish. If you don't plan to refinish, steel wool will remove the rust w/o doing too much damage to the finish in the areas surrounding the rust.

If you have rust in your bore, you're pretty much screwed. Sure, you can remove the rust, but you will be left with pitting, and pits is a dirty word. Not only that, but, like I said before, the rust will come back.