The topic is two fold. First your gun is NOT upgradable. At all really. And second, playing in your backyard is NOT a good idea. Do you really want someone calling the police on you and your friends? At best the police will confiscate your guns. At worse you'll face criminal charges and the risk of being shot for failing to comply with the order of a Police Officer. Getting shot isn't worth it, getting criminal charges isn't worth it, and having your gun siezed isn't worth it. So don't do it.