I have the SD700 airsoft sniper rifle. It was working good for a while but all of a sudden it started malfunctioning. Whenever I pull the bolt back to try and load it, there is a click and when I let go the bolt just shoots forward. It doesn't load and it won't shoot. I'm not exactly sure what the problem is. I think the spring might be broken, but I don't want to get a replacement part and then realize that actually wasn't the problem. Someone please help!