I am a guy just trying to get in the game but am inexperienced on guns, I would love to buy my own gun but am currently on a low budget and the most I can probably spend is 80$, I found a Tommy gun for 70$ (Auto and semi) and thought it to good to be true, it's at 240-250 fps in the description of the gun on the website (GI airsoft) but some people have said that they measure the fps with heavy BBs (.2) and that if you use .12 the fps should go up quit a bit, did I find a miracle temporary gun or just a money dump, HELP!