S&B would be for "Shot & Ball". There was a Charles W. Andrews of 6 Great Winchester Street, who retailed arms from the early 1890s up until 1900 where the trail goes cold. In 1894 the name was changed to include LLC or Ltd. A gunmaker named Charles E. Andrews of 15 Swallow Street, Piccadilly, was working in the late 1890s or just 1900. He more than likely was a decendent of Charles W. Andrews. Are the marks Birmingham or London? Could you post a pic?

Kind Regards,

Raimey
rse