What is RIS in Airsoft rifles and know when a gun is full metal?

Question

What does RIS stand for or mean in airsoft? Also, how may I know the difference when a gun is full metal from just metal gearbox with almost no pictures available or detailed photos?

Answer 1

With the second question you could look up the weight of the gun if they have it listed. a metal gun is going to be more than 3 pounds or so, depending on the style.