So I just received my first speargun. It's a Mares Bandit 75cm, and the flopper on the shaft is so loose it just dangles when you hold it with the flopper towards the ground. There's about a 2mm gap between the side of the flopper and the shaft. I haven't owned my own speargun before and don't know much about the different types of shafts but this seems kind of off. Is it supposed to be this loose? Or should it be tightened? Any response is appreciated.