As long as I know, yeah, they are the same thing, or al least look just the same.
It holds true to real firearms, as well. RIS is Rail Integration System, which is sometimes referred to as RAS (Rail Accessory System). It's the rail system for mounting accessories, such as tactical lights, optics, foregrips, etc.
Most airsoft RIS rails are the same size. it is safe to assume that an optic, light or otherwise will fit on any Weaver, Picitanny, or 20mm rail.
For the two-piece RIS, you simply pop off the standard heat shields, and replace them with the RIS. The KAC system has an allen screw which will need to be loosened prior to installation and tightened afterwards to secure them. The single piece free float rails are a different matter.
A gun, in your case an airsoft gun, that states that it has an s-system, such as a jg m4 s-system, is referring to an ris-system that the gun has. An ris system is a system of rails on which you can place various sights, scopes, flashlights, lasers, etc. I know because my airsoft gun is a double eagle m88 m4 s-system.
The population of Ris-Orangis is 26,863.
Walter Ris died in 1989.
Walter Ris was born in 1924.
Friedrich Ris died in 1931.
Friedrich Ris was born in 1867.
A gun, in your case an airsoft gun, that states that it has an s-system, such as a jg m4 s-system, is referring to an ris-system that the gun has. An ris system is a system of rails on which you can place various sights, scopes, flashlights, lasers, etc. I know because my airsoft gun is a double eagle m88 m4 s-system.
The area of Ris-Orangis is 8,710,000.0 square meters.
Azat-le-Ris's population is 290.