The Company’s greatest treasure is Armoury House itself. Earlier armouries had been built at the original Artillery Ground at Bishopsgate and at the Finsbury site to house the Company’s weapons and ammunition. Some account books and items of silver from the period prior to 1642 were taken away for safe-keeping by the Treasurer for the duration of the Civil War period but appear never to have been returned.

The Company began to acquire its fine collection of silver in the nineteenth century, mostly from shooting and other military competitions, and expanded the collection in the twentieth century from commemorative pieces acquired after the First World War (some of them by the silversmith Omar Ramsden). Paintings were presented of senior figures in the nineteenth century and early twentieth century.

The Company also owns some fine prints and drawings, especially by Adrian Hill (1895–1977), a member of the HAC’s 1st Battalion, who was an official war artist during the First World War.