The green and the yellow ones are kinda familiar to me. Here in germany guns are widely prohibited, thus people use pneumatic guns to cover their criminal careers. Pneumatic guns are shooting CS-gas, but also blank cartridges and they are rather popular with wannabe gangsters here in germany. In order to show your neighbours how gangster you really are, you can also acquire flares in order to celebrate the new years eve. Flares come in different sizes: For civilian use and bigger sized for hunters to flush ducks and other animals. The cap for the front with the thread might be useable to attach bigger charges of flares, which are released using a blank cartridge as propellant.
I'm not into firearms, so forgive my poor english regarding the case. A legal arms dealer should be able to help you sorting the bullets, I'd just make shure that the gun is legal before going there, or at least, that it is legal to own those bullets or to buy additional ones if you pretend to not own the appropriate gun.
