Gotta take this risk.

[Doctore]

Hmm maybe your parents think that pneumatic cannons are more like science experiments and maybe they think that real looking bb guns will make you aggressive and that real guns will start to interest you.
My other suggestion is to tell them that you are going to modify that pistol(add air supply or something) and that you are modifying it for a competition.

[warhead052]

Clem, I cant even buy a shell at this point.

Doc, I already love real guns. How would airsoft make me buy a real gun when I have friends who have them? I go to the range every now and then with friends and we open up like theres no tomorrow.

Their most common thing is "You dont need any when you keep borrowing from friends". Well, why do you think I keep borrowing?! Idiots....

[cammyd32]

I don't think trying to get round your parents is the way forward here, you need to try and persuade them somehow.

[inonickname]

I see what you mean, when I was young my parents would let me play "shooting killing games" at friends houses or borrow the games, but not buy them.

Look for toy guns (that make clicking noises etc), old water pistols, etc. Anything you can mock up.