Airsoft guns (/"softair guns) have the standard caliber 6 millimeters. There are also calibers 4.5 mm and 8 mm. In. 4.5 millimeter caliber, there are short and long guns that can shoot both lead diabolos and 4.5 millimeter BB's. On airsoft ranges, the 6 mm caliber has proven itself.
To ensure the best shooting performance, the weight of the BB should match the type and bullet pressure of the weapon. Often the weapon manufacturers specify a weight, but this can easily be exceeded or undercut to optimize the shooting performance of the softair weapons to the desired use.
In 6 mm caliber, the following bullet weights are recommended (bullet velocity, i.e. performance of the weapon taken into account):
0,12 g: Airsoft guns with less than 0.25 joules.
0,15 g: Application largely as for the 0.12 g BBs.
0,16 g: For softsoft guns under 0.5 joules.
0,18 g: For softair weapons under 0.5 joules
0.20 g: Standard weight of many airsoft weapons with 0.4-0.9 joules
0,23 g: Airsoft weapons with 0.4-0.9 joule
0,25 g: Upper limit for common airsoft guns. Slower than 0.20 g but more stable in trajectory and therefore more repeatable.
0.28 g: Standard weight for tuned, i.e. powerful airsoft weapons
0,29 g: Particularly high-quality BBs, very precisely manufactured. Suitable for airsoft precision rifles.
0.30 g: Standard weight for most airsoft precision rifles
0,36 g: Precision BB's. Particularly stable in trajectory, slower than the 0.30 g BB's but more repeatable
0,43 g: Graphite coated BB's, only suitable for the high quality upgraded airsoft guns.
0,85 g: Steel ammunition. Only usable for extremely tuned softair weapons, not suitable for the field.
For the BB's were usually plastic processed in different quality gradations. High quality BB's are then sometimes additionally polished or coated to achieve particularly precise and repeatable shooting results.
If the softairs are used outdoors, "bio-balls" are an environmentally friendly alternative to plastics, because they rot. Metal balls made of aluminum or steel are advantageous for very precise weapons, such as those commonly used in airsoft IPSC with a pistol or precision shooting with airsoft rifles.
Saving too much on airsoft ammo can be expensive, by the way: Cheap BB's can already break or deform in the airsoft gun and thus block the barrel of the gun and damage the expensive equipment.
Online, the best deals can be found at specialty retailers like Frankonia on marketplaces likeeGun or directly via Gunfinder product search.