As noted previously, there are multiple factors that will play a role in determining which weapon might be the best choice for home defense.
From a pure wound trauma standpoint on a shot against unarmored soft tissue, a close range hit from a 12 ga shotgun using buckshot will create more damage than any 5.56 mm projectile; it is for this reason that Dr. Fackler has expressed his preference for 12 ga buckshot over 5.56 mm for close range defensive use.
Compared to pistol caliber weapons, virtually any shoulder fired carbine caliber weapon or 12 ga shotgun will prove superior from a wound ballistic standpoint. Keep in mind that over the past 20 years, the vast majority of the 5.56mm/.223 loads we tested have exhibited significantly less penetration than 9mm, .40 S&W, .45 ACP, and 12 ga. shotgun projectiles after first penetrating through interior walls. Stray 5.56mm/.223 bullets seem to offer a reduced risk of injuring innocent bystanders and an inherent reduced risk of civil litigation in situations where bullets miss their intended target and enter or exit structures, thus 5.56mm/.223 caliber weapons may be safer to use in CQB situations, home defense scenarios, and in crowded urban environments than handgun service caliber or 12 ga. weapons. Below are the wound profiles of unobstructed shots at 3 meters, comparing several weapons that might be used for home defense:
Note that the M1 carbine, 16” barrel AR15, 18” barrel shotgun with a “youth” stock, and 16” barrel lever action carbine are all approximately the same length and offer the equivalent ease of maneuvering, so bickering about weapon size is a somewhat moot point when comparing weapons of this type. From an ergonomic and weapon manipulation standpoint, the AR15 is far superior to the other weapons, followed by the M1 carbine, and then distantly trailed by the shotgun and lever action carbine. Likewise, the AR15 is the most modular and allows the easiest mounting of various accessories. Unfortunately, AR15’s are also usually more expensive. In addition, in some locales, AR15’s are more highly regulated and/or feared than other less “scary” looking weapons; in those areas, an AR15’s “military” appearance may prejudice some LE officers who respond to a lethal force incident, as well as the DA and jury… If living in a state with asinine legal restrictions on firearms regulations or a liberal “weapon phobic” region, a PC, plain-jane appearing shoulder fired weapon that does not scare the metaphorical sheep might be prudent…
In an indoors static defensive role against a single violent assailant who was advancing on me, a 12 ga. shotgun would be my first choice. However, if multiple criminals were assaulting me, if a precision shot was required, if the assailant was wearing body armor, in a time of domestic unrest and upheaval with potentially large crowds of hostile individuals roaming about, or in situations that would require movement outdoors, then I would far prefer a magazine fed shoulder fired weapon capable of greater range, faster reloading, and greater ammunition capacity than a shotgun. In addition, of the shoulder fired weapons commonly used for self-defense, shotguns are the most difficult to effectively employ and require the most training to properly use.
Most citizens would do well to follow the lead of LE agencies in their locale and pick similar weapons to what LE feels is prudent and necessary for defensive use against the criminals in that jurisdiction. Often times these days that is 9 mm or .40 pistols with a 15-17 round magazines and AR15's with 30 rd magazines.
Finally, there is the matter of weapon familiarity and training. In 20+ years of military and LE use, I have fired far more rounds of ammunition, had more training with, and greater experience using AR15 based rifles than any other type of shoulder fired weapon. And while I have also trained with and used other shoulder fired weapons including MP5’s, M14’s/M1A’s, shotguns, bolt guns, and the odd M1 "Garand" rifle, M1 carbine, and lever gun—baring legal restrictions, in a chaotic, stress filled situation, I would feel most comfortable and confident using an AR15 based weapon due to my previous training and experience.
