The 7MM Blazer cartridge is not a standard or widely recognized ammunition type in the shooting and hunting communities. Most likely, there may be a confusion with similar calibers or brands. The 7mm caliber family includes a range of well-known cartridges such as the 7mm Remington Magnum, 7mm-08 Remington, and others, which are popular for their versatility in hunting medium to large game due to their excellent ballistic properties.
Blazer is a recognized brand under CCI/Speer, known for producing cost-effective, reliable ammunition mainly in calibers like .22 LR, and various handgun cartridges. However, Blazer is not typically associated with 7mm rifle cartridges.
For clarity, further specifics or context would be required to provide a detailed description.