Bolts are hardened, so carbide tooling needed.

As for opening up an AR bolt face, it can be done via C6 insert and flooding so you not changing the hardening on the bolt lugs by tooling heat.

In regards to the Sum extractor, its a new extractor with that shape, and not just a 308 extractor that was reworked instead.  Hence you should be able to just buy the new extractor from Armalite, instead of trying to rework a 308 extractor isntead.  Again, could be done, but would need to re-harden and tempered afterwards, so just easier to buy a new one from Armalite isntead.

FYI, Armalite and DPMS/stoner head spacing specs are different between their bolts and chambers.  So if you are going to use the armalite bolt once openned up, make sure that  the barrel is chambered to armalite head spacing specs (or send the barrel manufacturer the bolt so they can chamber the barrels head spacing to that bolt).