I don't know if you found this 'bit' ?
Thomas Firth supplied steel to the Royal Small Arms Factory at Enfield for the manufacture of rifle barrels, bayonets and other components, and it was their steel that helped make the world famous Colt revolvers unique in their day by having steel barrels and cylinders, unlike most manufacturers at the time who doggedly stuck to the traditional use of wrought iron.
Brown’s had, amongst other achievements, pioneered the rolling of armour plate and made the armour for HMS Warrior – Britain’s first iron warship. Soon after the discovery of stainless steel, the company would launch another of Britain’s most famous warships – the ill-fated HMS Hood.
The amalgamation of the two companies in 1903 to become Thomas Firth & John Brown Limited, usually known simply as Firth-Brown’s, was a natural step in uniting their interests. Likewise, their close relationship with the government made them the natural company to turn to early in 1912 when the War Department was seeking a better steel for rifle barrels – one that would resist wear more effectively and give the rifles a longer service life.