Normal Distribution Queries

 This is not meant to be condescending nor am I trying to start a flame war but your post suggests you do not have a clear understanding of the concepts of variation and distribution. The answers I’ve offered below are reasonable with respect to your specific questions but they are not the answers to the questions I think you meant to ask.
  A histogram of data from a normal distribution will provide an illustration of the variation of a process whose output is normally distributed – ordinary or special cause have nothing to do with it.
 If a process is normally distributed and if you make a histogram of the data then that histogram will illustrate the process and provide a visual assessment of the variation.  For the sample in question the illustration will provide a picture of 100% of the variation of the sample.
Variation doesn’t exceed a normal distribution or any other kind of distribution.  Variation is a measure of the spread of a distribution.
 

The statement “Special causes distort a normal distribution. ” is in error.
Normality does not imply an absence of special causes and non-normality does not imply the presence of special causes.
For the case of normal data with special causes present see the post below:
https://www.isixsigma.com/forum/showmessage.asp?messageID=123488
  As for the second – a process with a physical bound will produce non-normal data even when special causes are absent. As your in control process approaches the physical bound the non-normality of the data will increase and that non-normality will have nothing to do with special cause.