I have all 5.56 chambered AR15s. Just starting to load for this caliber after a long break (used up my commercial 5.56 WW stockpile) I still use 5.56 ammo for matches but want to start using reloads (again)
Have about 2000 rds to reload. Have the Dillon 550B setup with FL 223 dies, also the .223 trim and headspace dies. Of course, the Dillon primer pocket swaging tool.
Planning to use an old single stage press to pop the primers and resize the brass, then swage the primer pocket, then relaod.

OK, finally the question. If I am only using these reloads in the 5.56 chambered rifles ( I have no .223 chambers) do I go by the OAL cartrdidge length of 1.772 for 5.56 or do I stick with the .223 cartridge OAL of 1.760?
Will the FL .223 resize die set back the shoulder of the case, and should I not screw the die down so far it touches the base plate?

other suggestions welcome