The Gunsmith

Her real name is Véronique Sourd, but due to the underworld nature of her work and her Milieu connections she is better known by the epitet The Gunsmith
The Gunsmith was who designed the first prototype of the Beaumont Superweapon, although machining of components was contracted out in piecemail to various shops dabbling in Firearms, as no operation large enough to completely manufacture such a sophisticated piece of engineering exists. This member of the Milieu worked out of Stores in Stamps