Although accounts of his background are somewhat sketchy, it is believed that his father was an organ builder, while Harris had a tobacco wholesale business in London.

He was successful, and was often seen at various pigeon shoots at important London clubs, as well as leasing a grouse moor in Yorkshire.

Although Henry was a full partner, Harris kept strict control and was the only one who could sign a cheque until he died in 1896.

The last major development in the evolution of the sidelock side-by-side gun occurred in 1922, when the H&H assisted-opening mechanism was patented.

[3] In the period after World War II under the leadership of new owner and Managing Director Malcolm Lyell, the company made sorties to India, where guns from the famous collections of the princes and maharajahs were bought back, developing an important market for second-hand pieces.

A hand-built gun from H&H can cost around £60,000 for a shotgun and close to £100,000 for some rifles, with prices roughly doubling with luxury engraving, and there is a waiting period of 2–3 years between ordering and delivery.