The first charge increases the crit chance by 1.5, the second charge by 2. So if you have a base crit chance of 20%, at the first charge, your crit chance will be 30%, at the second charge, it will be 40%. It only affects the damage output with crits. It doesn’t affect the raw damage values.
The damage output changes when you crit. If you were to increase the crit chance for the shot, but not crit, it would do the same amount of damage as when it isn’t charged (in a non-crit). That is kind of what I meant to say. I can’t do words right now, I’m half listening to lecture, half writing on the forums