First of all, for airsoft BB , the most commonly used specification is 5.95mm domestic and foreign general specifications, which is often referred to as 6mm BB airsoft BB so the choice of airsoft BB is more a difference in weight. The commonly used weight specification is 0.2gBB Bullets, 0.25gairsoft BB, 0.28gBB bullets, 0.30gBB bullets and 0.32gBB bullets, but 0.20g BB bullets are the most used. For beginners who are new to CS sports to play BB bullets, using 0.2gBB bullets should be The best choice, because 0.2gBB can be used with any BB bullet gun, and the accuracy is easy to control and master.