The Portuguese Ammunition headstamps follow the the time line:
FA Fabrica De Armas (the 18th and 19th century general arms factory or "Arsenal" or "Armory" in US-Speak.
This Plant existed up to at least the First World War.
After WW I ( as early a 1919) a new headstamp became more common, the "AE" intertwined...Arsenal do Esercito..The Arsenal of the Army.
This headstamp lasted until 1937, when RWS and Mauser helped Portugal re-tool both Ammunition and Weapons facilities in Portugal, with a separate factory at Chelas, the FCPQ (Fabrica Cartuchoes e Polvoras Qimicas..Factory for Cartridges and Chemical Powders...ie a cartridge and explosives manufacturing facility.
This HS and facility lasted in HS form until 1949, when FNM ( Fabrica National de Municoes e Armas Ligeiras) was founded ( Factory of Munitions and Light Arms). and this HS goes from 1949 onwards( I have 7,9mm with FCPQ 48, and .303 Brit. with FNM 49 and FNM 50
Items such as Blanks were occasionally assembled at the Powder factories (ie, Barcarena), especially if they used "recycled" ball cases.
Also, Georg Roth (Austria) also supplied a lot of the origninal 8x60-56 cases up to the early 1900s (I have GR cases of 1900,03,04) and probably supervised the original machinery for making the Roth Patent Berdan primer Pocket design in the Portuguese cases marked "FA" (single flash-hole through centre of Anvil).
In the 18th and 19th, and even 20th centuries, many countries had all ordnance manufacture "under one roof"...so a factory produced the Powder, the cartridges and the Guns...sometimes in the one "location", sometimes is separate locations for safety pruposes, but under the one corporate/government control; Only the more advanced countires had a plurality of manufacturers, plants, and facilities to be distinguished by different markings.
EG, Spain's most Famous Arsenal, Toledo, made Swords, Bayonets, Artillery, and Cartridges, and even contained an Officer's School within the ancient Moorish Fortress, the Al-Cazar...the presence of the cartridge machinery allowed the Cadets to hold out against the Republican Reds, during the famous Siege, which was eventually lifted by Franco's troops coming from the East (having been flown in from Morocco by the German and Italian Air Forces )
Portugal's Ordnance History is interesting, going back to the days of Henry the Navigator (1400s).
regards, Doc AV