Please indulge me the permission to play Devil's advocate on this one, of all the studies of ballistics: shotgun ballistics are the hardest to nail down, there are many, many factors in this but for the sake of brevity I'll not go into all of them here. As you all know the sectional density and to a lesser degree the ballistic coefficient determines how far a round will penetrate at PBR or any distance to farther the distance the more ballistic coefficient comes into play. Shotgun pellets are not uniform in size, sectional density or ballistic coefficient: pellets are formed when molten lead is dropped from a shot tower, as the lead falls an cools the formation of pellets are a natural phenomena: there aren't any forms involved. When the pellets drop they are then sorted by size and loaded into the shells. Hardness of the pellet is determined by the amount of antimony that is added to lead, pellets sized 6 and smaller have little antimony added so the soft lead deforms easily, and doesn't penetrate well.
Secondly ballistic performance of shotshells on plywood, drywall and other similarly brittle materials have little correlation to how the shot will perform on the human body. The human body is a soft target, which sounds like the performance of the shot would be more devastating not less, but in fact it is far less.
There are three components to penetration in soft targets: Strength, Viscosity, and density of the target. Ed Lowry explained that soft target have all three qualities. Robins' wood had strength as the primary factor, a constant unrelated to velocity. Viscosity, whether tar, grease, honey, is proportional to the velocity. Density, as in water, cork, dust, is proportional to the square of the velocity, as explained by Ed Lowry. (quote from shotgunning ballistics article found here http://www.chuckhawks.com/pellet_penetration.htm) (Ed Lowry was known as the "Dean of Shotgunning Ballistics)
In other words whatever you shoot a human target with must contain enough sectional density, velocity and energy to overcome the elasticity of skin, density of muscle and bone, and finally the viscosity of blood; before reaching vital organs. Probably the most striking evidence of this is the attempted assassination of Theodore Roosevelt. His handwritten speech and heavily muscled pectorals stopped the .38 caliber bullet fired from a Colt revolver at 10 feet. He gave a 90 minute speech before seeking medical attention.
Here is another ballistics study on the efficacy of small shot shotshells http://www.theboxotruth.com/the-box-o-truth-3-the-shotgun-meets-the-box-o-truth/ Here is one of the quotes that I feel is pertinent to this discussion
Birdshot as a Defense Load
I have had a lot of questions, summed up as follows: How effective is birdshot (#4, #6, #8, etc.) as a defense load?
We have done tests with various birdshot loads. Birdshot penetrated through two pieces of drywall (representing one wall) and was stopped in the paper on the front of the second wall. The problem with birdshot is that it does not penetrate enough to be effective as a defense round. Birdshot is designed to bring down little birds.
Then there are these real world reports from the same article:
A policeman told of seeing a guy shot at close range with a load of 12 gauge birdshot, and was not even knocked down. He was still walking around when the EMTs got there. It was an ugly, shallow wound, but did not STOP the guy. And that is what we want… to STOP the bad guy from whatever he is doing. To do this, you must have a load that will reach the vitals of the bad guy. Birdshot will not do this.
“I saw a gunshot victim, about 5′ 10″ and 200 lbs, taken to the operating room with a shotgun wound to the chest. He was shot at a range of six feet at a distance of just over the pectoralis muscle. He was sitting on his front porch and walked to the ambulance. We explored the chest after x-rays were taken. The ER doc had said ‘buckshot’ wound, but this was obviously not accurate.
It was # 6 shot. There was a crater in the skin over an inch in diameter. When the shot hit the level of the ribs, it spread out about five inches. There was ONE pellet that had passed between the ribs and entered the pericardium, but not damaged the heart at all. As you say, ‘use birdshot for little birds.’”
Also, here is another article utilizing ballistics gelatin as the target, however carefully note the conditions the author tells the reader about. Additionally note that there is no bone placed in the gelatin and the actual shot would penetrate even less in real world conditions. http://www.thetruthaboutguns.com/2010/02/robert-farago/shotgun-penetration-with-various-rounds/
Finally the ugly truth about shooting a shotgun at close range, pattern size. Many people mistakenly think that they have a better chance of hitting the
target using a shotgun, however at ranges of 12 feet and less the shot shell pattern will only be approximately 2-3 inches wide at 12 feet and much much less at 3 feet, utilizing an open bore choke, i.e. no choke. Unless you modify the muzzle of the shotgun to spread the load immediately upon the shot exiting the barrel, a duckbill choke does this nicely.
What gun and ammunition people use as their home defense is 100% a personal choice, and I'm not trying to change your opinion or tell you your opinion is wrong. Rather it is to point out that there is allot of misinformation being passed off as truth, not nefariously but from a lack of understanding terminal ballistics. Shooting a hole in plywood doesn't equate to shooting a hole in a bad guy.
As this video from youtube would have you believe
