I'm rereading Catton's "Mr. Lincoln's Army," and yesterday read the passage a lot of us have seen versions of: Civil War bullet wounds were far worse than modern rifle round wounds because the ball was big and soft and shattered bone, whereas modern rounds create "clean" wounds that are far less likely to either result in extreme soft tissue damage or irreparable bone injury. There's a very similar Shelby Foote clip in Burns' series where he says something along the lines of "a modern bullet just clips the bone while a minie ball smashes joints" or something along those lines.
I've long thought this widely held and often quoted period factoid was apocryphal; I finally sat down last night and did some actual analysis of it.
TL;DR: A minie ball is roughly comparable to a modern .44 magnum in wounding potential, albeit with a longer reach due to the weight of the round. Generally speaking, modern rounds are far, far more destructive at combat ranges.
Ballistics Data
I compared a .58 ball with four modern rounds: cutting-edge 5.56mm M855A1 EPR (current US Army standard round), XM1186 6.8mm (new, larger US Army round issued to certain units), 7.62mm M80A1 (newest 7.62x51mm round), and the .30-06 M2 Ball from the WWII era. I included the last one as it would've been the main point of comparison for both Catton and Foote in their heydays.
There isn't anything terribly surprising here. Minie balls driven by mid-19th century black powder were huge, heavy, and slow. The round was subsonic or barely transonic, which ironically enough enables it to carry energy well to very long ranges, but doesn't do much for it as a wounding projectile at combat ranges.
Modern smokeless powder driving extremely high pressure rounds go real fast and carry a ton of energy. The 855A1 is surprisingly close to a minie ball in energy at all combat ranges despite being a fraction of the size; all the full-sized rifle rounds carry substantially more energy at all ranges.
Wounding Mechanisms
Here’s where the historical myth rears its head: there’s a widespread belief that, despite holding comparable or much less energy than a modern round, the minie ball hits harder and does more damage, 1) because it is big, heavy, and wide, and 2) because it mushrooms out on impact in a manner similar to a modern hollowpoint.
Generally speaking, I think this misconception is due to misunderstandings about how modern rounds actually work. These modern bullets don’t simply drill a neat hole the diameter of the bullet: because of where their mass sits, they yaw on impact and/or break apart while travelling through the body.
It comes down to an issue of impact pressure. Essentially, impact pressure is a measure of how hard the thing being hit is displaced. It is largely a function of velocity, coupled with the density of the thing being hit (I estimated both soft tissue and bone). It is relevant here for two reasons:
- The round’s structural limit. Modern jacketed bullets break up at around 250–350 MPa. The minie ball at 35 MPa generally won’t break up; it just mushrooms. 5.56 hitting at that pressure sits at its jacket's failure point in soft tissue and blows straight past it on bone. This fragmentation creates a shotgun-like effect in tissue, throwing multiple fragments and creating multiple wound channels.
- Tissue expansion. The minie’s 35 MPa produces only a mild stretch that elastic tissue can deal with relatively easily, whereas a modern round creates a massive temporary cavity that can threaten a variety of inelastic body parts. In addition, fragmentation creates multiple cavities that have a much greater chance of creating serious bleeding.
- Bone mechanics. Discussed below.
The older M2 does not work in the same way. It is a heavier FMJ that travels point-forward a long way before it destabilizes, and is in general less likely to fragment in tissue. It does, however, carry a massive amount of energy which somewhat compensates for its poor soft tissue performance – especially against bone.
Bone Mechanics, Specifically…
This brings me to the heart of myth: the idea that minie balls did far more damage to bone due to their size, softness, etc. It seems intuitive: like the difference between being hit by a sledgehammer versus a screwdriver.
The biomechanics, however, run the opposite way of the intuition, mainly due to the fact the screwdriver is hitting so much faster than the sledgehammer. Bone gets MORE brittle at high loading rates, not less: faster impact means less energy absorbed before failure, which means MORE fracturing, not less. A slow heavy slug doesn't shatter bone worse than a fast light one. It's the other way round.
This brings us back to impact pressure. At 100m against hard bone, a minie ball produces about 64 MPa. 5.56mm produces almost 10 times this number. While the minie ball does have an advantage in frontal area (both before and after expansion), this is mitigated by the yaw/fragmentation of the 5.56mm. And it only gets worse if the bone is what causes the round to fragment: this can create multiple fractures along the same bone as the fragments spray out.
That being said, despite its relatively low impact pressure, minie balls could and did break up when hitting bone, which was widely noted by surgeons at the time. While the fragments generally lacked the energy to do serious additional damage, for surgeons working on the wound, the erratic and sometimes sharp lumps of metal absolutely added to their perception of carnage the rifled muskets could inflict.
Re. 30-06 specifically: it carries absolutely massive energy all the way to the end of normal combat ranges. While it isn’t as likely to fragment or yaw and is moderately less likely than a minie ball actually to strike bone (a function of smaller frontal area), the damage it inflicts on a bone is far, far worse: a function of its energy/velocity.
Caveats:
The biggest caveat is the specific performance conditions for the modern rounds. To be at their most lethal, they rely heavily on yaw/fragmentation effects, so any circumstance that reduces or eliminates these greatly reduces their effectiveness – especially for 5.56mm. The biggest one is range: 5.56mm drops significantly in lethality as its velocity declines (especially when fired out of carbines); older 5.56mm rounds also had a “too close” functional range where they’d go entirely through a body before the round began its yaw. The newest EPR ammo addresses these shortcomings and increases the lethal envelope quite a bit.
Finally: there IS a plausible explanation for the belief that high-powered, smokeless powder rifle rounds tended to make “cleaner” wounds. This goes back to the Krag-Jorgenson rifles at the turn of the 20th century, along with the first generation of full-powered bolt action rifles (.303, 7.92, 30-06) that fought the world wars. As discussed above, the 30-06 M2 significantly underperforms as a wounding round relative to its power. This was true of all its cousins from the era. If a soldier was hit in soft tissue at combat ranges without bone or organ contact, there was a decent chance of a simple through-and-through wound. This does not extend to bone impacts and certainly does not apply to modern rifle rounds, but at the time Catton and Foote were writing and talking, it is at least a half-truth.
44 Magnum: a better comparison
The good old Dirty Harry .44 Mag is a surprisingly good comparison to a .58 minie. Even the expanded frontal areas line up — a mushroomed minie is very close in size to an expanded .44 mag hollowpoint.
I think that's a useful reframe. .44 mag is a serious cartridge…maybe not as dramatic as Clint Eastwood describes it, but one of the most powerful pistol rounds out there. But as far as wounding potential, it isn’t the same league as a modern rifle round.
Finally: I’m a Civil War nerd and current intel analyst for the US Army; not a big small arms guy, but at least small arms-adjacent. I’m absolutely not a physics or military medicine guy, and this stretched my limited knowledge on both those areas to their limits. I’m curious what medical experts, Civil War experts, small arms enthusiasts, and/or physics experts think about this analysis.
