Why it matters: Ammunition makers often post side-by-side wound photos to show what their bullets do. This video works through what one of those comparisons shows about bullet construction and distance, and what it cannot show about velocity.
Boondock Ballistician's video "How Velocity Kills And When It Doesn't Matter," published on YouTube on November 1, is a talk-to-camera explainer on wound and terminal ballistics. The host, who goes by Boondock, uses it to respond to a social media post from Discreet Ballistics and to set out what velocity does, and does not do, when a bullet strikes tissue.
Discreet Ballistics post: 6.5 Creedmoor vs .300 Blackout Selous
As described in the video, the Discreet Ballistics post placed two heart shots side by side: one from a 6.5 Creedmoor and one from the company's 188-grain .300 Blackout Selous load. Boondock says the post's point was that muzzle energy is not the whole story, since the .300 Blackout wound looked worse despite the round carrying less energy. Boondock agrees with that point, calls the company's products "fantastic," and says the post was not "disingenuous in any way." The Reticle has not located the original post.
Boondock's concern is how the comparison could be read. Both shots would be fatal, the host says; the difference lies in what each bullet was built to do. The 6.5 Creedmoor bullet was a Hornady 135-grain A-Tip, a match projectile intended for target shooting rather than hunting. Boondock also points to the distances: the A-Tip was fired at 165 yards and the 188-grain bullet at 75 yards. (At one point the video attributes the 75-yard shot to the 6.5 Creedmoor; the 188-grain weight is the Selous.) According to Boondock, a 6.5 Creedmoor match round fired into gel at point-blank range would look far more destructive than it did at 165 yards.
What bullet velocity does to tissue, according to the video
The middle of the video covers the wounding effects Boondock ties to velocity alone. Above a certain speed, the host says, a rifle bullet produces what the video calls "tail splash," a rearward push of tissue and fluid at the entrance, along with a temporary cavity. Boondock says the speed at which this matters is "very largely debated" and is quoted anywhere from 2,000 to 2,700 feet per second, and that for handgun rounds the temporary cavity is "a side effect" that does little to organs.
Boondock argues that gel testing at the traditional 10 to 15 feet overstates what the same rifle round does at 100 or 200 yards, after velocity has dropped. Tissue type also matters in the video's account: lungs are described as elastic and able to absorb stretch, the liver less so, and bone, fat and air spaces each change the outcome. The host says much human tissue can stretch to about six times its normal size before tearing, and that a fast enough entry and exit can cause a drop in blood pressure severe enough to cost voluntary motor control. The video does not cite sources for those figures.
Boondock's summary of this section is that a match bullet can kill when used within its effective velocity range, but that this "winds up being a very limited working range," and that a terminal bullet "will do everything else and that much more."
Hollow point expansion, tumbling and fragmenting bullets
“Both shots would kill, the host says; what the photo shows is two bullets built for different jobs, fired at different distances.”
Avery Lindqvist, The ReticleFor slower rounds, Boondock says, bullet construction makes up for the missing velocity. The Selous is a hollow point, and the video describes tissue entering the cavity and forcing the bullet open, which enlarges the permanent wound channel. Boondock adds that hollow points behave differently in gel than in tissue: gel moves aside, while tissue stacks up in front of the bullet and limits how far it travels.
The host describes tumbling bullets as producing a similar enlarged cavity "a lot less predictably," and fragmenting bullets as spreading damage across a wider area, which raises the chance of reaching more vital structures. Every one of these mechanisms has a working range, Boondock says, and modern materials and engineering are lowering the velocities at which they function.
The video closes with two comparisons. Between a 9mm expanding bullet and a 5.56 full metal jacket, Boondock says nearly everyone would choose to be hit by the 9mm, because the 5.56's velocity alone is more likely to kill with one shot. Between 9mm full metal jacket and 9mm expanding, the host's point is that without rifle velocity, the hollow point design "winds up compensating."
Boondock's conclusion is that there is "no one right answer" to what makes a shot fatal, and that the useful questions are what working range, velocity and caliber a shooter needs. Boondock also says a video on the Selous load may follow at some point.
For context
- Discreet Ballistics announced its 188-grain .300 Blackout Selous subsonic load in 2017; the machined copper bullet, developed with Peregrine Bullets, is designed to expand at 750 feet per second and above.
- Hornady's 135-grain A-Tip Match is a 6.5mm boat-tail bullet with a machined aluminum tip, built for long-range target shooting.
- The 2,000-feet-per-second line often used to define "high velocity" is a convention rather than a measured damage threshold, and wound ballistics researcher Martin Fackler argued that the roles of velocity and the temporary cavity had been overstated.
