The method and formula for calculating the plastic hollow floating ball weight is as follows, diameter little plastic hollow floating ball weight is not balanced, so the plastic hollow floating ball weight is to take the average value will be accurate, 50 grain plastic hollow floating ball, divided into five groups to weighing, each said 10 grains, and weigh out the weight divided by 10 is a plastic hollow floating ball weight, and then the other four groups of plastic hollow floating ball weighing, adds weight to five groups of and divided by 50 is a plastic hollow floating ball exact weight. Plastic BB ball volume calculation formula is as follows. The volume of plastic BB ball to calculate accurately, it is necessary to ensure the high precision of the measured plastic BB ball, diameter tolerances must be to small, plastic BB ball standard is 5.95 + 0.01 mm, only such precision plastic BB ball to ball volume formula to calculate accurate plastic BB pellet volume and ball volume V to represent and Pi Pi =3.15924, R is diameter, BB plastic ball diameter is the assumption that 5.95mm, so is V=4*3.15*5.95 no / apply ball volume formula to calculate 5.95mm plastic BB ball volume is 88.4 mm3. .