Attached to the mag tube I have a small 3 rail attached. One is for a light. On the bottom one I’d like to put a sling stud. Does anyone make such a thing?
You may find what you’re looking for here:
http://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_id=80
Try this http://www.brownells.com/.aspx/pid=24169/Product/AR_15_M16_RAIL_MOUNT_QD_SLING_SWIVEL it is from Daniel Defense and comes with the adapter and quick detach swivel. I use one on my carbine’s two point sling and love it.