General Questions
This takes time, but yes, they will biodegrade. The more dense (heavy) the BB is, the long this will take. Expect BBs to still be visible for many months after they are used.
We recommend you bleed off and remove partially spent CO2 cartridges that are left in your CO2 powered airsoft gun. Storing the gun with a pierced CO2 cartridge in it will lead to premature seal failure.
Airsoft BBs are made of plastic or an organic compound that can biodegrade in time. Depending on the BB you buy, you will typically pay more money for biodegradable style BBs.
Airsoft guns are best used for airsoft battle or skirmishes but many people have started using licensed airsoft replicas for force-on-force training, personal defense training, and speed shooting drills.
A barrel cover is used to signal to airsoft participants that you are not actively participating in a skirmish or otherwise demonstrate safety when transporting your airsoft rifle without a bag.