No, I do not think you should buy your 15 year old a pellet gun. I see nothing wrong with someone of that age (or younger) having a gun if they are mature and can responsibly handle one. My opinion is due to what you said about YOUR son-you already told him that he needed to improve his grades first, which he has not done. Then he had a temper tantrum when you told him no. That is not responsible, mature behavior and certainly would not get any child of mine what they are asking for. If his attitude is already so bad, a potential weapon is not a good idea for him. Nevermind that since you apparently live within the city limits of Las Vegas, it is illegal anyway. If you purchase a gun for your teenaged son, I think you are opening yourself up for a whole lot of trouble. Again, I have nothing against guns-we own several, and my children are younger than your son and they do use a pellet gun (supervised) and as they age, they will be taught to properly care for and handle the other guns. It is just your son's attitude that makes me think that NO, he should NOT have a gun-pellet or not. I hope this helps.