18mm Swiss Prelaz-Burnand Cartridge or somthing else?

Hello everyone. I’m trying to find out if this in indeed an 18mm Prelaz-Burnand cartridge or something else. It is indeed similar but the projectile within the cartridge has three grooves instead of the typical one groove projectile. This one measures L 1.600" D .733" or 18.66 mm

IMG_3681 IMG_3680 IMG_3682 IMG_3684