What should I do about this in my story?

So I want one of my characters to be good with weapons. But I don't know much about weapons. However, my story takes place in 2104 so I could just cheat and make up weapons (ex. ray gun, death blaster, light-saber etc. etc.) BUT I didn't want the times to be much more advanced than now, I kind of wanted it to go backwards. Should I just research weapons of this age and change them a little to fit my story? Or just make up weapons? AH confusion!