Armand Henrion, T. Dassy & Victor Heuschen used the following:
http://www.littlegun.be/arme%20belge/artisans%20identifies%20h/a%20h%20d%20h%20gb.htmSpecial steel Martin Siemens
Super-dreadnought
Terrible Bull
The Royal
The Talisman
Best Shot
cross axes (two) and a die showing the face of the three
Etourdissor
H&D
H&D Automatic Pistol Obvious
halberds (two) and a die showing the face five
HD and patented
((NOTE HD alone is NOT their trademark but that of Henri Devillers.))
HDH with or without square around
Matagatos
Suffocant
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Lucien Clement used the following:
Liègeoise
Spangled steel
Special steel with two cross hammers
Steel Fine Extra Inhabitant of Liège
The Américan Settler
The English Bullock
The Franco-Russian One
The Guardian Américan model of 1878
The Washinton
ACCT
Bull's eye
cartridge of or leaves the flashes with the initial LC of each with dimensions
CCNM
perron of Liege surrounded of the letters L and C
Compressed Steel with a marine wheel.
Crucible cast steel with initial the DC interlaced
Decarburated Steel
Fluss-Stahl with a haume preceded
Fulgor
giraffe
Hammered Fluid Steel with two cross hammers and initial DC AA
Hammered Fluid Steel with two cross hammers and initial DC LC
LC
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This is an early etching of the Lucien Clement shop. Notice 2 things. There is an electric light hanging over head. The workman is using a hydraulic barrel straightener, most likely purchased from the British.
Both Clement and HDH were hugh shops. Yes they were barrel makers, just as Pieper was. None of them had a smelter or ran a foundry. They were purchasing raw stock and then supplying the trade. They also produced weapons and ammunition under various house brands.
If the above trade marks are a tad "rough" as they are still auto translated. My list is very large, over 2,000. I haven't had the time / ambition to clean it all up. Some day..... It is also entirely possible that some trademarks of either firm are missing from the above lists.
Because LC and Siemans appear on the same barrel does not mean Clement was dealing in Siemans steel, at least in my mind. HDH could have supplied the tubes and Clement joined them. Or a dozen other scenarios. These makers often formed associations for a particular contract. Tomorrow they would become competitors once again.
Pete