Its all about luck. I think it works by this theory. Say for example the chances of winning the weapon is 1 in 5000. So people buy the crates until the number keeps going down until the person that buys the 5000th crates wins the weapon. And in that 5000 crates they add maybe 20 crates where you are two spaces away and 10 crates where you are one space away. Or it could be based on time. A person wins every 5 minutes. I dont think it matters where you spin it but it matters when you spin it at the right time.