Royal Small Arms Factory was created in 1816.
Several companies.Royal Small Arms Factory Enfield (United Kingdom)Royal Small Arms Factory Sparkbrook (United Kingdom)Birmingham Small Arms Company (United Kingdom)London Small Arms Company (United Kingdom)Royal Ordnance Factory Fazakerley (United Kingdom)Royal Ordnance Factory Maltby (United Kingdom)Lithgow Small Arms Factory (Australia)Longbranch Arsenal (Canada)Ishapore Rifle Factory (India)Pakistan Ordnance Factories (Pakistan)Savage Arms (United States of America)
"Enfield" refers to the Royal Small Arms Factory in Enfield, United Kingdom, and the name "Enfield" is applied to small arms manufactured or designed by the Royal Small Arms Factory (even if they didn't come specifically from the Enfield factory). There are several models of pistols and rifles which bear the name "Enfield", the most famous of which is the Short Magazine Lee Enfield rifle.
Small Arms School Corps was created in 1853.
Birmingham Small Arms Company was created in 1919.
You're probably thinking Royal Arsenal, known to some as the Royal Gun Factory, which was closed down in 1994. It was an arms manufacturer in London.
I'd be interested to know what type of firearm you saw this on. The first one which comes to mind is the Royal Small Arms Factories (such as the infamous Enfield factory).
Each arsenal left their own distinct marking on the weapons they manufactured:Enfield - Royal Small Arms Factory at Enfield, United KingdomSparkbrook - Royal Small Arms Factory at Sparkbrook, United KingdomBSA, BSA Co., B, or M47C - Birmingham Small Arms Company, United Kingdom. The "B" and "M47C" markings were on No. 4 rifles, with the "M47C" markings indicating they were made at the Shirley facility.LSA Co. - London Small Arms Company, United KingdomLithgow - Lithgow Small Arms Factory, AustraliaGRI - Ishapore Small Arms Factory, pre-independence IndiaG - Ishapore Small Arms Factory, post independence IndiaROF (F) - Royal Ordinance Factory Farlakerzey, United Kingdom (No. 4 rifles)ROF (M) - Royal Ordinance Factory Maltby, United Kingdom (No. 4 rifles)Longbranch - Longbranch Arsenal, Canada (No. 4 rifles)US PROPERTY, US PROPERTY [S] - Savage Arms, United States of America. They were made for the Lend-Lease Programme (No. 4 rifles)POF - Pakistan Ordinance Factories, Pakistan (No. 4 rifles)No. 3 rifles will have the rear sight ahead of the chamber, close to the centre of the rifle, while No. 4 rifles will have the rear sight behind the action, at the rear of the receiver. Additionally, No. 4 rifles adopted a simplified spike bayonet in place of the sword bayonet used on earlier No. 3 rifles. No. 4 rifles will also have a manufacture date of 1939 or later, whereas the No. 3 rifles were manufactured from 1907, with production at most facilities ceasing in 1945, although India manufactured them until 1960, and later produced the 2A and 2A1 rifles, which were essentially SMLE No. 3 rifles, chambered ijn 7.62x51 NATO, from 1963 to 1975.
The First Bren Mark 1 LMG was built in the Royal Small Arms factory in Enfield Lock in England during September 1937, although preparations for its manufacture had begun in 1934.
An arms factory is a place where weapons are produced.
Assuming that you are talking about the BSA small arms factory, November 19th 1940.
See the link to the Royal coat of arms of the United Kingdom
Royal Ordnance, BAE Systems, and now Heckler & Koch.