King cobra stun gun not shooting electricity/working but it does work, why?

I have a King cobra 5.8 million volt stun gun, and yes it is legal in my area. Often the sound of the electricity popping is enough to stop physical aults and leads to the least violent conclusion. I recharged it the other day and then flipped off the safety and turned it on to test it but nothing happened. I put it against my arm and pushed the on and it still had a current but not near enough to put anyone down and there was no flashing of electricity, popping or smell of ozone. Whats wrong with this thing?