Longrange

I wondered about the human factor being as all of my personal long range work involves animals only.

Here is a humorous picture that illustrates the differences in body sizes of animals.

One of the problems with those "special scopes" is that, as you said 18 inches is an average with a spread that puts you right out of ballistic capability. You are holding fine example of not 18 inches in the chest.

Also a bit smaller then you. ;)