RDIAS, Registered Drop in Auto Sear. It's a little piece of metal that is considered a machine gun (M-16) that you can drop in most AR15 lowers and it acts as the sear. All you have to add are the other M-16 parts, hammer, trigger, disconnect, selector and something else and you?re ready to rock in role. The beauty of the RDIAS is that you don't have to worry about wearing out a registered lower. They?re practically un-destroyable. You could buy a MGI lower and use it with all the different configurations they have or order a Ciener belt fed semi lower and your ready to rock in roll with a belt fed. Ciener?s left fed lower receiver has several cuts in the receiver that I would want to have added to a registered M-16 lower.
Call Spencer and he can make you a sample sear. It shouldn?t cost but around $100. My next MG will be a RDIAS but I?ll still keep the register receiver. 2 kids, M-16 for each when they get older.