A must have!! - Obsidian Arms AR-15 Upper Receiver Vice Block

I bought this after watching a video on YouTube about installing a barrel. The video went in depth on vise blocks and action rods. I had already owned a couple different styles for upper receivers to include a action rod but I liked the points that the guy had made about this style of vise block. This was also my first time installing a barrel so I wanted to make sure I had a couple options incase I had any issues. Well I ended up only needing this vise block and I now use it for a lot of the upper receiver tinkering I do with my AR's.