The big news so far from the U.S. Army’s search for a new sidearm isn’t about what kind of pistol they’ll choose, but rather the bullets they might shoot.

In a significant shift, the military told industry representatives last week that it’s considering switching from full metal jacket to hollow-point rounds for its standard-issue sidearm ammunition. While hollow points are commonly used by police and civilians, they are banned in international warfare under the 1899 Hague Convention‘s early laws of war that the United States has followed even though the U.S. government never ratified the agreement.

Military lawyers say the move isn’t meant to skirt international law, but instead embrace the changing face of warfare. “The notion that [in modern warfare] two states agree to Marquess of Queensberry Rules is very archaic,” Richard Jackson, a special assistant to the Army Judge Advocate General for Law of War Matters, tells The Trace.

Hollow points, also known as dum-dum rounds, are designed to expand or break apart upon impact. The rounds quickly transfer all their kinetic energy to a target, resulting in a bigger, more devastating wound. Full metal jacket or ball ammunition — the type the Army currently uses — holds together, causing smaller wound channels and often passing straight through targets.

But even as militaries backed away from the rounds after the first Hague Convention found the bullets’ capacity for expanding wounds and tearing flesh inhumane, police forces around the world readily adopted hollow points, including the U.S. Military Police. The practice has few critics: Police overwhelmingly use the rounds in handguns, which deliver a sixth of the force of a rifle and therefore render the bullets’ expanding quality less devastating than the rifle rounds that prompted the Hague ban. Since they expand and flatten on impact, the bullets are also believed to be safer and more effective in close quarters, as they’re less likely to pass through a body and harm bystanders, and an officer firing them may need fewer shots to stop an attacker.

According to Jackson, the Army has to weigh military necessity (how well does a bullet incapacitate an enemy?) with humanitarian concerns (does the bullet cause unnecessary suffering, or make death more inevitable?) to determine if bullets are acceptable under the laws of war. Those laws of war, he argues, were developed in a different era of combat, when sovereign states fought each other; today, the Army finds itself engaged against non-state actors like Al Qaeda, often in crowded urban centers. Army lawyers have only said they’re considering hollow points as sidearm ammo, not for rifles, so that would be consistent with police use.

“There’s a humanitarian interest benefit to the use of bullets that don’t exit,” says Jackson. “We’ve been interested in them for close-quarters battle with enemies that use civilians as shields or hostages.”

But Jackson added that a new standard for military ammunition would not be “carte blanche” for the Army to use any kind of bullet it so chooses. There are other hypothetical ways bullets could fail to meet law of war standards, according to Jackson: If they contained glass or plastic fragments that could tear flesh while remaining undetectable by medical X-rays, for instance.

When asked about what laws would apply to Army soldiers deployed with hollow points on an unconventional battlefield in the vicinity of civilians, as they often were in Iraq, Jackson pointed to the standard described by the International Court of Justice in the Corfu Channel case, a landmark decision on the military use of force outside of declared war. States’ “obligations are based, not on the Hague Convention … which is applicable in time of war, but on certain general and well-recognized principles, namely: elementary considerations of humanity, even more exacting in peace than in war.” The Army argued that these bullets could meet these standards given their widespread use by police, and shouldn’t raise concerns that they violate international laws or norms.

It’s an axiom that the civilian gun market follows the lead of military and police buyers (the AR-15 rifle and Glock semiautomatic pistols are bestsellers partly because they were popularized by soldiers and cops). Questions about the Army’s possible adoption of hollow points leading to increased popularity of the ammunition with civilians fell outside Jackson’s offices’ legal purview. From a marketing perspective, though, it’s hard to imagine serious gun buyers aren’t already intimately familiar with hollow-point bullets. Every large ammunition company offers them for sale to the general public. Only one state, New Jersey, seriously regulates their use, and even there, they aren’t totally prohibited. For decades, your average Joe has been able to more readily arm himself with hollow points than his buddy G.I.

[Photo: Flickr user Kenny Alexander]