A few weeks ago at the local flea market I saw this for sale. Unfortunatley I didn’t buy it as the seller was an antique dealer and had a price of £120 on it. I took some photos as I thought the shotshell collectors might be interested.
Most probably know this, but Smokeless Diamond was an early double base Nitro powder made by Curtis’s and Harvey Ltd.
The shell was made from copper. The brass head seemed to be indentical to other shotshells I have seen with this headstamp. I believe the diamond was cast aluminium.