Invest the only one concept from that number, let it be that: avoid inexpensive BBs at all charge! Minimal rank airsoft BBs are found in sporting things shops and Wal-Mart. They are occasionally called "Smooth Airsoft 0.20g" or "Smooth Airsoft 0.12g" BBs but don't let the name fool you, they are sub-par BBs and must be avoided. These inexpensive BBs separate aside too easily, leading to jams, stripped pistons, and cracked gears.