What an awesome spam can never seem one like this before! That v section of sheet metal looks like it could remove your hand! Do you have any idea about the time period this is from?
A lot of surplus ammo was badly stored, and is unreliable and even dangerous to shoot. Most is Berdan primed and corrosive. Greek HXP is one of the more notable exceptions to this rule. Good quality brass, non-corrosive, and reloadable. I wish I had bought more when I had the chance
As @davidbliss3220 mentioned, this is later production. The label can be seen at the beginning of the video. HXP-75 indicates it was made in 1975 Mk7z is the loading and the z indicates it uses nitrocelulose powder rather than cordite. Good question though.