See Also : Airsoft Pellet Guns by Type...
Lighter airsoft pellet guns achieve higher velocities, but are more prone to influence from external factors like wind. Lighter airsoft pellet guns also decelerate (lose velocity) faster than heavier airsoft pellet guns.
The curvature of a projectile (trajectory) determines its range and heavier airoscft pellet guns tend to have slower velocities which result in much more curved trajectories. This can be negated in part by the use of a hop-up.
Heavier airsoft pellet guns may require a more powerful airsoft guns and often necessitates upgraded spring of airsoft guns and other airsoft guns parts.

A player's choice of pellet weight is governed by their gaming style, airsoft gun (internals), game location (in/outdoor), high/low range and fps regulations.
0.12 g airsoft pellet guns. Used by all low grade airsoft guns such as some spring airsoft gun pistols, which can use 0.20 and mini electrics airsoft guns. High velocity and low stability. Not to be used in high end electric airsoft guns such as Tokyo Marui and Classic Army.
0.15 g airsoft pellet guns. Same uses as 0.12 g. This is uncommon pellet for airsoft guns. Not to be used in high end electric airsoft guns (AEGs) such as Tokyo Marui and Classic Army.
0.16 g pellet of airsoft guns. Essentially the same as the 0.15 g pellets. Very uncommon for airsoft guns.
0.20 g pellet of airsoft guns. Standard weight for most airsoft guns. Electric airsoft guns (AEGs) use these or slightly heavier pellets.
0.23 g pellet of airsoft guns. Heavier pellets for electric airsoft guns (AEGs). Blends speed of 0.20 g with range and accuracy of 0.25 g. Made popular by Tsunami Airsoft.
0.24 g pellet of airsoft guns. An oddity. Only known manufacturers are Airstrike (a subsidiary of Daisy) and Crosman.
0.25 g pellet of airsoft guns. Heaviest weight for standard electric airsoft guns (AEGs), blowback airosft guns and spring airsoft guns. Tokyo Marui standard electric airsoft guns, gas airsoft guns, and spring airsoft guns are set at the factory for 0.25 gram BB's, and they usually include a package of 200 of these with the airsoft guns.
0.28 g pellet of airsoft guns. For upgraded electric airsoft guns (AEGs) or airsoft sniper rifle guns. Significantly cheaper than 0.30 g but yields similar performance.
0.29 g pellet of airsoft guns. Maruzen Super Grandmaster BBs, designed for their Air Precision Shooting series of airsoft guns. One of the most precisely ground and accurate BBs available, but cost more than other alternatives. These also can come in aluminum versions, which will hurt more than plastic.
0.30 g pellet of airsoft guns. Standard weight for most airsoft sniper rifle guns. Western Arms pellets for their airsoft gas blowback pistol series. This is uncommon pellet of airsoft guns.
0.36 g pellet of airsoft guns. Heavier pellets for airsoft sniper rifle guns. Very slow but have high stability.
0.43 g pellet of airsoft guns. For the highest level of upgrades in spring airsoft guns and airsoft gas sniper rifle guns. This pellet of airsoft guns usually graphite coated.
0.88 g pellet of airsoft guns. Possibly the heaviest type of BB available. Usually made of steel and comes with a polished finish. Rarely used and often hard to find.

0.27 g pellet of airsoft guns. Low weight.
0.34 g pellet of airsoft guns. Normal or Standard weight for airsoft guns.
0.35 g pellet of airsoft guns. Biodegradable- Standard weight.
0.45 g pellet of airsoft guns. Heaviest weight for airsoft guns.
See Also : Airsoft Pellet Guns by Type...