Complex sentence: The London Armoury Company flourished due to the manufacture of the Adams revolver, however, in 1859 the company's board of directors decided to increase the production of infantry rifles, decreasing revolver production.
Split into simpler sentences: The London Armoury Company flourished due to the manufacture of the Adams revolver. However in 1859 the company's board of directors decided to increase the production of infantry rifles, decreasing revolver production.