In actual use, there is no possibility of contact between the BB bomb and the inner tube. There are many reasons for contact here. From the perspective of BB bombs, there may be reasons such as low processing accuracy, low true sphericity (that is, eccentricity), rough surface processing, etc., but it may be seen from the BB gun side. There are cylinder exhaust flow instability, air flow fluctuations and other reasons. Once the collision, the frictional resistance will inevitably affect the initial velocity of the BB bomb and cause the BB bomb to rebound in the opposite direction to the contact point, resulting in a vicious circle. If the barrel is long enough, the final shot will return to the shaft of the barrel under the rectification of the air flow; however, this is not possible in an inner tube of limited length on the BB gun. From this point of view, another effect of the TN inner tube on improving the accuracy of the hit is that the internal TN coating greatly reduces the friction coefficient, so that the BB bomb has a small speed loss and is easier to reset when it contacts the inner tube.

Another important factor affecting the accuracy of BB hits is mentioned in the above paragraph - that is the cylinder volume. According to common sense, the larger the capacity of the cylinder, the greater the gas flow rate of the spit, then the BB bomb should fly farther and more accurate? In fact, it is not necessary that the cylinder capacity must be considered in conjunction with the length of the inner tube. For a certain cylinder capacity, there will be a corresponding optimal inner tube length, the inner tube is too short, the BB bomb is fired without being fully accelerated, and the cylinder volume is no longer used; and if the inner tube is too long, Will cause the BB bomb to lose the best time to "out", so that the inner tube gradually slows down, and the copper inner tube is too long, it is easy to cause resonance (barrel vibration - BB bomb and inner tube contact ... will cause What results will not have to be said). Everyone has a chance to look at the small holes in the cylinders of MARUI that are "leaked" on the cylinders. 

That is the so-called "accelerated" cylinders, which can increase the rate of fire, but will reduce the effective volume accordingly. The BB guns using accelerating cylinders are almost all short and fine. Although the length of the inner tube is short, because of the better fit with the cylinder volume, there is no significant difference in range and accuracy compared with other original guns with longer inner tubes. .