Originally Posted by Omnivorous
RAS stands for Rail Accessory System and RIS stands for Rail Interface System. They are pretty much the same thing. RAS is a free float as opposed to RIS. Since RAS is connected straight to the receiver, it tends to be more stable than RIS, which is connected to the delta ring.
I think I got it right...
Oh. Snap, I've always wondered about this. Now I know.
And knowing is half the battle! lol