I thought my button dated between 1843-1863 because in the link I found the same link bigcypresshunter posted it gives the dates of manufacture based on what the button says on the back. The only years I seen sons on the back was 1843-1863. Mine says sons and then PHI it does not show the PHI on that sight. Also the buttons they made with the Philadelphia mark say PHILA or just Philadelphia. Ive been looking at general service buttons and I haven't found one with the same shape sheild as mine, I know their were different manufactures but I still cant find the same one as mine. Thanks guys for all your help I dont know much about buttons so all help is greatly appreciated.