1. Load attached repo mission in singleplayer/editor
2. Upon loading two supply crates will be in front of you, the left having one EBR the right having two.
3. Grab the EBR out of the left crate, note that you can zero it. Drop it or put it back in the crate.
4. Grab an EBR out of the right crate, note that this particular EBR cannot be zeroed even though they're the exact same weapon class.