The 8mm-06 cartridge is a wildcat rifle round, created by resizing and necking up the .30-06 Springfield cartridge case to accept an 8mm (.323 inch) bullet. It was developed to allow American hunters and shooters to utilize surplus 8mm Mauser ("7.92×57mm Mauser") bullets with the more readily available .30-06 brass.
This cartridge is often used for hunting medium to large game due to its powerful ballistics and effective range. It provides a higher velocity and slightly improved performance over the 8mm Mauser cartridge by benefiting from the larger case capacity of the .30-06, resulting in more propellant and, consequently, higher speeds and energies.
The 8mm-06 was more popular in the mid-20th century, primarily among handloaders and custom rifle builders. It never achieved widespread commercial success and typically requires handloading due to limited factory ammunition availability. Conversion from .30-06 to 8mm-06 generally involves rebarreling or rechambering a rifle and can make use of existing .30-06 components easily available in the United States.