Re: AR-15 DIAS is their such a thing??
The M16 does not use a DIAS. It does use an auto sear, that is built into the lower receiver. There is a separate pin for it above the selector switch. A (Registered) Drop In Auto Sear ((R)DIAS is a device pictured above that gets dropped into an AR15 to convert it to full-auto like an M16. You need M16 fire control group (trigger, selector, bolt carrier, etc) to make the package work. A lightning link is a different device that is dropped in on a standard semi-auto fire control group that converts it to full auto. As I understand it, you don't need a full-auto selector or hammer, although you do need a full-auto or appropriatly modified BCG to make it work.