I'm looking for a good bore guide for my AR15. I have been looking at one made by JP Enterprises and one made by Satern Machining. These are very similar except the Satern is made of Delrin and the JP is made from anodized aluminum. How good are these? Anyone have experience with the Satern one? Are there any other good guides to consider? Thanks for taking the time to answer my questions! Pics of each in the attachments below.

