A specialty BB that is 4.5mm in diameter and unlike its armor piercing heavy aluminum brother the coppertop, will push in excess of 800fps out of a spring powered daisy 340, let alone anything CO2. CO2 is pushing nearly 2500 fps with a blaster .13g as opposed to a coppertop .35g 4.5mm made out of high density PVC.
You better stop falsifying documents or your going to catch a blaster .177!