Phil

The firm "Fried Krupp" was founded way back in 1810 as steelmaker and manufacturer of heavy ordnance. Some of the early "milestones" of the company are;
1811 - First smelting furnace
1843 - First cast steel cannon barrels
1843 - First artillery oiece - 3 pounder
1854 - Their first 12 pounder
1886 - Biggest gun in the world - 42 foot barrel/16.5" bore/2,300 pound shell that could penetrate a 3 foot steel plate at a range of a mile (the breech closure alone weighed 120 tons!
1890 - 5000 ton hydraulic press for the manufacture of armour plate.

In 1896 Krupp's had an English agent, Mr. Aug. Reichwald who resided at Dashwood House, 9 Broad Street, London and claimed that Krupp barrels were stronger than their oppositions' (Webley) by virtue of having some residual tension, but cautioned that brazing would remove it. (Amatuer Gunsmiths take note)

Up until WW1, Krupp and Webleys between them supplied most of the gun and rifle tubes to the English gun trade, but following the war, Krupps lost their English trade, with the Vickers Company stepping in to take their place.

In addition to the "GUSSSTAHL" marking, a trademark made up of three interlinked circles was often used. Some "makers", notably W.J.Jeffery's and Alexander Hollis(read Leonard) left these markings on, but is almost certain that others removed them.