7.62mm bullet keychain

thingiverse

Went to the shooting range, picked up a discarded bullet casing, brought it back home, transformed it into a keychain. The 3D printed replica of a bullet was carefully pressed into the casing and appears to stay securely in place without any issues. You can always add a small amount of adhesive to ensure it doesn't come loose over time. A hole measuring 3/16 inches is drilled near the rim to fit a key ring, which also renders the cartridge completely non-operational.