It appears to have been a true grazing wound, with the bullet passing perhaps 1 or 2mm deep into the tissue rather than an equal distance away from it. I couldn't find any support for the idea that a fired bullet of this type produces any boundary layer of high-velocity air whatsoever.
You beat me to it!
Grazes from bullets are not unknown, where the bullet flies parallel and just in contact with a skin surface.
Entry wounds from bullets can be little larger than the bullet calibre.
Those statements are supported in "Practical Pathology of Gunshot Wounds", J. Scott Denton, Adrienne Segovia and James A. Filkins, 2006,
Archives of Pathology and Laboratory Medicine 130 (9);
Be advised, photographs of gunshot injury and fatalities,
https://meridian.allenpress.com/aplm/article/130/9/1283/459975/Practical-Pathology-of-Gunshot-Wounds
I recall man-in-the-crowd quotations from people who served in combat, and contested that the particular ammunition used could not possibly have nicked an ear without doing far more damage.
The perpetrator, Thomas Matthew Crooks, used a 5.56x45mm AR-15 -style rifle. 5.56x54mm is the standard US/ NATO rifle calibre, and is also used by many other nations and by private individuals, local circumstances allowing. There are different manufacturers using different propellant loads and bullet designs, but differences in energy imparted are a matter of degree (within 15% across common types for a given barrel length, as far as I can tell).
The 5.56mm round is faster, but significantly less energetic, than its predecessor in US/ NATO service, the 7.62x51mm:
(Wikipedia
5.65x45mm NATO;
7.62x51mm NATO).
Most rifle rounds of the WW2 combatants were a little more powerful still, often firing 10-13g bullets at speeds of 800-850 m/s, with energies very approximately in the range of 3400-4000 J.
The 5.56mm round is fearsome but not unusually powerful.
Bullet tumbling, deformation or fragmentation are probably irrelevant in this context of (at most) a glancing contact at approx130 metres, other than to say there are modifications a shooter can make to a bullet, in the hope of causing increased damage to a target, which might increase risk of fragmentation in flight; such modification also impairs accuracy. We have no evidence Crooks used ammunition altered in this way (but it is possible).
External Quote:
The original ammunition for the M16 was the 55-grain M193 cartridge. When fired from a 20 in (510 mm) barrel at ranges of up to 300 feet (100 m), the thin-jacketed lead-cored round travelled fast enough (above 2,900 ft/s (880 m/s)) that the force of striking a human body would cause the round to yaw (or tumble) and fragment into about a dozen pieces of various sizes thus created wounds that were out of proportion to its caliber. These wounds were so devastating that many considered the M16 to be an inhumane weapon.
...With the development of the M16A2, the new 62-grain M855 cartridge was adopted in 1983. The heavier bullet had more energy and was made with a steel core to penetrate Soviet body armor. However, this caused less fragmentation on impact and reduced effects against targets without armor, both of which lessened kinetic energy transfer and wounding ability.
Wikipedia,
M16 rifle (former US service rifle derived from the original military AR-15, and using the same 5.56x45 ammunition).
The M16 has a 20" barrel and imparts a higher muzzle velocity and therefore energy than a 16" barrel as used by Crooks.
Even if Crooks were using ammunition more prone to fragmentation (e.g. M193), it is unlikely to have fragmented at the range (c. 130 metres) used,
Above is based on part of a ballistics reference chart posted by
RockyMtnTactical, post #34 on
The Firing Line Forums.
Can't vouch for its origins or accuracy, but muzzle velocities and energies are in line with other sources.
Combat veterans may have seen the terrible damage that bullets (including 5.56mm and equivalents) can do. Depending on the bullet's path through the target, cavitation effects- damage to large volumes of tissue much larger than the bullet's size- might be visible; exit wounds are sometimes (but not invariably) much larger than entry wounds. Large cavitation usually requires the bullet to travel through several cm/ approx. 2+ inches of tissue before occurring.
"
Wound profiles in ballistic gelatin", Wikipedia
M16 rifle. The diagram is for a 5.56x45mm ss109/ M855 NATO fired from a 20" barrel. (Ballistic gelatine does not perfectly model human tissues; the temporary cavitation on the entry surface, vertical line at left of diagram, is not evident in entry wounds portrayed in the
Practical Pathology of Gunshot Wounds article.)
Bones may be shattered with predictably grim results, particularly for skull injuries.
Such injuries observed in a casualty surely draw the attention more than, e.g., grazes perhaps sustained by the same individual.
The ballistics reference tables for 5.56x45mm ammunition posted at
The Firing Line Forums provide this information on the M855 round (and equivalent tables for other 5.56x45 types, including the earlier M193). I don't know what specific ammunition Crooks used or what types are commercially popular in America; but I'm guessing M855, the standard military round, might be popular, and it is broadly representative of 5.56x45mm ammunition:
(Original capture edited; figures unchanged). Crooks' AR-15 -style rifle had a 16" barrel, as per the two middle columns above.
From this, we can get an impression of the energy lost over distance by 5.56mm bullets shot from a 16" barrel:
I think
@Edward Current is right, it's unlikely that kinetic energy "lost" from a 5.56mm bullet to the surrounding air will be able to cause injury to the skin.
All credible evidence very strongly suggests that Thomas Matthew Crooks, using his AR-15 -style rifle, took several shots in the direction of Donald Trump at the rally near Butler, Pennsylvania, 13 July 2024 (Wikipedia,
Attempted assassination of Donald Trump in Pennsylvania). One man was killed, two others seriously injured. Crooks was wounded when his rifle stock was struck by fire from a local policeman, and killed by a US Secret Service sniper a few seconds later.
It must highly,
highly likely that Crooks was attempting to kill Trump; the 16" barrel AR-15 provided him with a very real chance of being successful over the distance involved.
I'm not sure it's credible that Trump was equipped with the means to fake or self-inflict a minor injury should a would-be assassin
miss, while the attack is still underway!
On balance, I think the most likely explanation is that Trump's right ear was -just- clipped by a 5.56mm round, deliberately fired at Trump by Crooks.