You're right. I had forgotten. It's been awhile since I've played around with the AR.I don't believe that the gas key or protrusion in the 9mm bolts is related to charging handle function. I did think that until closely looking at it today. I will find out tomorrow after I remove the gas key. My belief now is that the little shelf on the carrier is what the charging handle grabs on to to draw it rearward and also draws the charging handle forward when released. See pic.View attachment 603507