Before anybody can really talk about defensive ammunition, some basics need to be laid down. Knowledge (and acceptance) of some basic information and facts will dispell a lot of myths. It will avoid circle talk about what birdshot does to sheetrock, oil drums, or whatever. It doesn't matter what it does to those items: nobody who is paid to study terminal ballistics uses them or anything like them as determination of anything beyond patterning. Patterning is only a small part of terminal ballistics.
http://www.firearmstactical.com/pdf/fbi-hwfe.pdf
While this is a paper on the wounding effects of handgun projos, there is some good basic info that translates to any projectile wound. The goals are the same: only the means of delivering the projo are different. In modern ballistics and projectile technology, shotgun projos (in terms of buck and birdshot) are actually in some ways similar in that they are not high velocity rounds, such as from a carbine or rifle. Buck and birdshot are actually in many ways poorer penetrators than pistol rounds due to their shape, construction, and velocity.
Pay particular attention to the purpose of shooting an attacker, the definition of immediate incapacitation, the mechanics of projectile wounds (which do not include a central focus on energy), the fact that kinetic energy does not wound, the myth of knockdown power, the myth of temporary cavitation or stretch cavity, the human target and physiology, the ability to remain a threat even after the heart has been destroyed, the need for deep penetration in order to immediately incapacitate, ammunition selection criteria, the importance of mass in penetration, the dangers of shallow penetration, the predispostition to fall down, disparaging of laboratory methods, and what lab tests and scientific research in the field of terminal ballistics actually does.
Finally, if you want to seriously look at the field of terminal ballistics and see what real tests look like, the sources in this paper would be a very good start.
http://www.shotgunworld.com/bbs/viewtop ... 7&t=109958
This is a thread on ballistics gel tests for shotgun rounds. Keep in mind that the gel in these tests was improperly prepared, and will OVER represent the penetration of the pellets by a factor of between 10-25% depending on the block in question. Please note that even with that in place, NO birdshot pellet reaches the minimum 12" of penetration. None.
http://www.firearmstactical.com/briefs10.htm
Here's a post on defensive shotgun ammunition. Keep in mind that it is from 1998, and some of the info is dated. Some of the rounds are not available, and a lot of technology has improved since the time this was written. However, a lot of the info in the article as to basic facts remains true. From that source:
Firearmstactical.com said:
Birdshot, because of its small size, does not have the mass and sectional density to penetrate deeply enough to reliably reach and damage critical blood distribution organs. Although birdshot can destroy a great volume of tissue at close range, the permanent crush cavity is usually less than 6 inches deep, and this is not deep enough to reliably include the heart or great blood vessels of the abdomen. A gruesome, shallow wound in the torso does not guarantee a quick stop, especially if the bad guy is chemically intoxicated or psychotic. If the tissue crushed by the pellets does not include a vital cardiovascular structure there's no reason for it to be an effective wound.
Many people load their shotguns with birdshot, usually #6 shot or smaller, to minimize interior wall penetration. Number 6 lead birdshot, when propelled at 1300 fps, has a maximum penetration depth potential of about 5 inches in standard ordnance gelatin. Not all of the pellets penetrate this deeply however; most of the shot will penetrate about 4 inches.
http://www.shotgunworld.com/bbs/viewtop ... ght=docgkr
Some info on barrier penetration and various firearms projectiles.
http://www.m4carbine.net/showthread.php?t=56486
DocGKR said:
Failures to stop a suspect because of under-penetration, poor bullet placement, and completely missing the target are far more significant problems than over-penetration.
http://www.m4carbine.net/showthread.php?t=34714
Some info on basic wound ballistics.
DocGKR said:
The last 25 years of modern wound ballistic research has demonstrated yet again what historical reports have always indicated--that there are only two valid methods of incapacitation: one based on psychological factors and the other physiological damage. People are often rapidly psychologically incapacitated by minor wounds that are not immediately physiologically incapacitating. Psychological factors are also the reason people can receive severe, even non-survivable wounds and continue functioning for short periods of time. Up to fifty percent of those individuals rapidly incapacitated by bullet wounds are probably incapacitated for psychological rather than physiological reasons. Psychological incapacitation is an extremely erratic, highly variable, and completely unpredictable human response, independent of any inherent characteristics of a particular projectile.
DocGKR said:
Absent CNS damage, circulatory system collapse from severe disruption of the vital organs and blood vessels in the torso is the only other reliable method of physiological incapacitation from small arms.
Of particular note:
Dr Newguard via DocGKR said:
“A 70 kg male has a cardiac output of around 5.5 liters per minute. His blood volume is about 4200 cc. Assuming that his cardiac output can double under stress, his aortic blood flow can reach 11 Liters per minute. If this male had his thoracic aorta totally severed, it would take him 4.6 seconds to lose 20% of his total blood volume. This is the minimum amount of time in which a person could lose 20% of his blood volume from one point of injury. A marginally trained person can fire at a rate of two shots per second. In 4.6 seconds there could easily be 9 shots of return fire before the assailant’s activity is neutralized. Note this analysis does not account for oxygen contained in the blood already perusing the brain that will keep the brain functioning for an even longer period of time.”
Keep in mind this is a complete severing of the thoracic aorta. On a small, thin target standing perfectly squared with no intervening structures this will require at least 7" of penetration. Birdshot doesn't do this.
