Doesn't work - Barska AR Quad Picatinny

I hate to be critical of a product but unfortunately this doesn't work. I had a friend put together an ar pistol for me with this rail and it wasn't centered and he couldn't even install the gas tube. So I had to buy a new rail. And before someone thinks my friend doesn't know what he is doing he works on guns all the time and he put together my LR-308 and it is perfect! My guess is this best works for an airsoft gun, which is a total bummer because I was really hoping this would work.