The March 2007 issue of American Rifleman, page 44 states "...a red groove on the extractor double as a loaded-chamber indicator."
My AR24-15 does not appear to have this feature. In fact, there is no visual difference in the exterior footprint between an empty and loaded chamber.
Does the AR24-15 have a loaded chamber indicator? Or is the author of the article in error or perhaps he had a prototype and this feature was not incorporated in the production unit. Could it be, there is something amiss with my AR24?

I don't have that answer, but I am curious how you like the AR-24, and have you taken it to the range for a shooting session.
There is a painted red notch in the extractor that moves outward slightly when a cartridge is in the breech face. There's been a change in the extractor that makes this feature somewhat difficult to see, and it may eliminate the outward movement. We're checking into it now.
In the final analysis, the best thing to do is to assume the pistol is chambered regardless of the indicator.
Sorry about the confusion.