I achieved to double capital within some hours. It is about volatility and your leverage.
If you're ready to accept risks, then you can easily to double and triple your investment.
But if you want to grow your capital steadily without taking high risks, then you need more time
It has got the risk, and here the user is lucky to get the investment doubled in few hours. This won't happen with everyone, but with the present market situation there is more chances for growth. Also as the market is down, we get to invest at a much lower price which increases the chance of doubling our investment anytime soon.