please excuse the low post count, im new post-wise to arfcom, but not "hours of my life wasted"-wise, you all are a very informative and knowledgeable bunch. :) now that the pleasantries are out of the way...
correct me if I am wrong,
with an AR 15 set up to run a RDIAS: low shelf, m16 FCG, :
if the RDIAS is removed, and the selector positioned on AUTO, and then fired, :
will the hammer follow the bolt without being caught by the sear, thus causing a mis-timing condition and fire out of battery(before the bolt is fully forward and the locking lugs locked, ie, dangerous)???

or does the RDIAS engage the disconnector(?) , thus letting the disconnector halt the hammer?

or am i mistaken about the disconnectors role?

trying to build a SAFE and LEGAL rifle able to accept an RDIAS, this is the last thing I am unsure about, I wouldnt want to leave the M16 FCG in it  if its unsafe on AUTO

thanks for anything and everything guys

-Matt

NOT LEGAL (the rest I will NOT COMMENT ON)...RDIAS THEN S/F/F selector...no RDIAS... NO S/F/F selector.... BAD JUJU...

You are mistaken about the disconnector's role.

No sear, set to auto, the hammer will follow the bolt carrier into battery, resulting in the hammer down on a live, unfired round.  It spends all its energy on the bolt carrier, and cannot generally ignite a standard primer.

M16/AR-15 cannot fire out of battery from this, because the firing pin is too short to reach until the bolt is already fully closed, and at least partially locked.

Don't put or leave an M16 FCG in a rifle without the auto sear installed.  ATF does claim this to be an illegal configuration.  Even if you can't get reliable full auto fire out of it (you can't), they consider it to be an illegal machinegun if they can get it to fire more than one shot in that configuration, even once.

this is 100 percent the answer I was looking for. thank you. I will be leaving the semi auto FCG in it until a range day with a RDIAS. the "partial, unreliable full auto" legal issue was the other concern, but not worth mentioning if its not safe to use the rifle that way anyway. thank you. thats what yall are here for.