The difference with AR 10's is a DPMS style and an Armalite style. The barrel nut, threading on the receiver, bolt, bolt carrier and barrel extension are different. There are more using DPMS style then the AR10 style. Bushmaster, DPMS, gap, mega arms and LMT is DPMS style. Armalite and Christensen Arms is Armalite stlye. I am unsure on LWRC and Christensen arms has said they will more than likely be offering both styles and some point.
You can run one stlye in the other as long as you use the same style barrel extension, bolt and bolt carrier. Example is I built my girl friend an AR-10 with a Mega Arms receiver(DPMS style) using a Christensen Arms carbon fiber barrel and hand guard(Armalite). Had to use an Armalite carrier and bolt to match up with the barrel extension.