https://www.tngun.com/skip-shooting-a-shotgun/
In today's article on Skip Shooting a shotgun we are going to talk about a technique taught in many correctional academies for dealing with riots. While most of us will never have to worry about dealing with inmate riots, the ability for one man with a shotgun to be able to hit multiple assailants with one shot may be useful.
We have covered in other videos the concept that while the column of shot fired from a shotgun does spread, it is not as extreme as Hollywood shows in the movies. Basically the shot spreads an inch every 10 feet or so. The low mass of the individual shot also cause it to loose potential energy very rapidly. Taken together, by the time the shot spreads enough to hit 3 or 4 bad guys, it won't have enough energy to actually stop them.
However, as the video demonstrates, if you shoot your shotgun at a low angle, and hit solid ground a foot or two in front of your target, the rounds will “skip” up and spread. Additionally, if your firing at asphalt, gravel, or other like substance, some ground debris will also be added to the ricocheting shot.
Now, before we get illusions of ninjas and super secret squirrel stuff (S4) take into consideration the basic laws of physics, and realize that action has a reaction. By spreading the shot in such an extreme manner there is an additional loss of velocity. Also, depending on the distance from the target, the angle, and how far you hit the ground in front of the target the maximum height you will get impact on the target will vary. It will be somewhere from the shins to the hips.
Less shot will impact the target, with less velocity, in the bad guy's legs instead of vital organs. That is a very significant trade off for hitting more than one guy at a time.
While I think this is a good technique to keep in the brain housing group, if I was in a situation where I was in fear for my life by multiple attackers in close proximity I think I would be better off shooting the biggest threat center mass than peppering multiple guys.