While some may discount The Box O’ Truth (e.g. exactly how scientific is it), there’s still some merit in what was presented — it’s still food for thought, especially regarding things like buckshot patterning. So on the topic of ammo, not only do we want something good enough to stop the bad guys, but we also want something that minimizes risk of over-penetration especially in a home-defense situation.
The reality is, if you want it to penetrate the bad guy enough to make them stop, it’s going to have some risk of over-penetration (e.g. ability to go through common household walls). But depending on your ammo choice you can have greater or reduced issues to deal with.
So let’s see what one of the top resources has to say about choice in .223 ammo. Or from Troy & Dr. Gary Roberts. Now granted, what they write there is .223/5.56x45mm specific, but based on part 1 and part 2 of this series you can see where my bias lies. Nevertheless, let’s look at what Dr. Gary Roberts, LCDR, USNR, Stanford University Medical Center. Dr. Roberts has performed much published research into this matter and is a well-respected man in this field.
Given the widespread availability of this information for over a decade, I am shockingly surprised to read about the “overpenetration” with “high powered assault rifles”. In this day and age anyone who is spouting this BS needs to be horsewhipped… Several respected organizations have done structural wall testing, including the FBI, CHP, and IWBA. In our IWBA and CHP testing, replicas of standard construction interior walls were fabricated using two pieces of 1/2″ thick dry wall cut in 12″ x 24″ segments and mounted four inches apart using 2 x 4″ fir studs and 1.5″ dry wall screws. Five rounds of each load were first fired into bare gelatin to serve as controls. Then 5 shots of each load were shot through interior wall segments into gelatin blocks placed a set distance behind the intermediate barriers–various distances have been tested, typically ranging from 1 to 10 feet.
Generally, common service caliber JHP bullets failed to expand and had very deep, excessive penetration after passing through the interior wall, due to plugging of the hollow point. With the hollow point plugged, the bullets performed nearly identically to FMJ pistol bullets. The terminal performance of the 12 ga. 00 buckshot and slugs was not altered by passing through interior wall replicas, with penetration and deformation nearly identical with their performance in bare gelatin. Likewise, .308 rounds were not usually effected by the presence of an interior wall intermediate barrier.
With one exception, the majority of the 5.56 mm/.223 loads, including M855 62 gr “green-tip” FMJ, which were fired through interior walls demonstrated either minimal changes in terminal performance compared with bare gelatin or reduced penetration. The major exception were 55 gr M193 style FMJ projectiles which exhibited minimal fragmentation and deformation after first passing through interior wall replicas and hence penetrated deeper than in bare gel. Since all of the 5.56 mm/.223 bullets fired through the interior wall had significantly less penetration than 9 mm, .40 S&W, .45 ACP, and 12 ga. shotgun projectiles which were fired through an interior wall, stray 5.56 mm/.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. As such, 5.56mm/.223 caliber weapons may be safer to use in CQB situations and crowded urban environments than service caliber handguns or 12 ga. weapons.
Obviously, it is important to keep in mind that purpose built barrier blind 5.56 mm/.223 projectiles, such as the 55 & 62 gr Federal Tactical JSP’s and the Nosler 60 gr Partition, will offer deeper penetration than fragmenting designs and may exit.
So as you can see, there’s something to be said for 5.56/.223 loads in a home-defense situation. And what fires those loads? Generally, rifles. And what’s generally going to be a better rifle for a home-defense situation, with corners, narrow hallways, darkened rooms? Your AR-style platform, or perhaps an “M4-gery” because it’s a bit more compact.
While ammo selection is certainly important, while your choice of hardware is certainly important, I’d argue there’s something more important: a proper warrior mindset combined with proper training/instruction and practice.