With most slot machines, it’s impossible to tell when a slot machine is ready to hit for two main reasons. The first reason is that slot machines spin very high speeds, which are designed to trick the human eye. Second, the machine doesn’t automatically stop when you hit the slot.It will wind down until it comes to a complete stop, making winning a very hard task. Though, there are some slot machines named “must hit by”, which means you can visually tell when the jackpot is ready to hit.For these slots, there are at least two kinds of jackpots, both minor and major.