I am having a custom rilfe built. While searching around the web for information I ran across this site. I was wondering if any of you guys have ever used the aluminum alloy 20 MOA Picatinny rails on your rifles? I am having a 300 win mag built and the builder is wanting to put these on the rifle. Like all things I like talking to put who have used them before I spent the money on it. So any information and details would be great.