I fixed up the OP'd parts of the application, and I feel it is much more suitable now.
Change 1: From his time in gangs he learned how to fashion metals down to the bare parts of weapons, and turn even common house-toys into proper weapons that would fire bullets as efficiently as any regular gun would. Though his weapons were indeed useful, and very convienient, they had a higher chance of failing and locking up than other guns would. While they were not perfect, they did serve their purpose.
Change 2: -The guns he can make are never perfect, at best they turn out a little worse than a normal gun. They tend to lock up, and sometimes backfire, injuring him so he will have to continue working on the project even later to perfect the weapon