The Army is considering the use of expanding and fragmenting ammunition, such as hollow point bullets, to increase its next-generation handgun's ability to stop an enemy.
This bit of news was revealed Tuesday, during the service's fourth industry day for its Modular Handgun System.
After a recent legal review within the Pentagon, the Army can consider adopting "special purpose ammunition," said Richard Jackson, special assistant to the Army Judge Advocate General for Law of War, according to an Army news release. This marks a departure from battlefield practices over a century old.
Jackson told Army Times that while this isn't the first approved use of such bullets in the military, the stance represented "a significant re-interpretation of the legal standard" for ammunition. He also said a lot has changed since the initial movements against the round, especially with the increased prevalence of asymmetric warfare.
"There's a myth that [expanding/fragmenting bullets] are prohibited in international armed conflict, but that doesn't make any sense now," Jackson said.
More than 20 manufacturers are 
vying to make the Army's next handgun, dubbed the XM-17. The solicitation for the contract is to produce more than 280,000 guns for the Army, and is expected to drop later this month, said Lt. Col. Terry Russell, program manager for individual weapons at Program Executive Office Soldier. First deliveries are currently slated for 2018.
Most of the Army uses full metal jacket, or ball ammunition, in both handguns and rifles. These rounds are designed to hold together, increasing penetration and narrowing the tunnel of damaged tissue.
Expanding and fragmenting bullets can flatten or break apart, and are more likely to remain in the body of a target and transfer all of their energy to it. A wider swath of tissue is typically destroyed.
Modern complaints against the M9 have included stopping power. The potential shift toward hollow point ammunition could allow manufacturers a tool to change the ballistics equation substantially, without a shift away from the 9 mm round. Advantages of a 9 mm round include theoretically larger magazine capacity (because of a smaller bullet) and adherence to the NATO standard, allowing for interoperability of the allied nations' weapons.
On the battlefield, the U.S. has generally observed the 1899 Hague Convention rule barring expanding and fragmenting rounds, despite the fact that it never has been signatory to that particular agreement, Russell said.
The U.S. reserved the right to use different ammunition where it saw a need. For example, Criminal Investigations Command and military police use hollow points — as do law enforcement agencies around the country — in part to minimize collateral damage of bullets passing through the target. Special Forces also uses expanding/fragmenting rounds in counter-terrorism missions.
Jackson said a 1907 Hague convention dictated the legal standard by which the Pentagon would hold the new weapon system to. He said it prohibits a weapon from being "calculated to cause superfluous injury and unnecessary suffering." That means probability of enemy incapacitation, the military requirement, has to outweigh any unnecessary damage, he said.
The use of fragmenting ammunition is "widespread" among law enforcement and counter-terrorist forces said, according to an email from Army spokesman William Layer.
"The use of this ammunition supports the international law principles of preventing excessive collateral effects and safeguarding civilian lives," an Army statement said.
In theory, the Pentagon appears to have legally justified broader use that could include rifle rounds, Russell said, though he also called the standard issue 5.56 mm Enhanced Performance Round (M855A1) "a very good performing round."
"I don't know that there would be a necessity to have another round, but I'm not the requirements writer, either," Russell said.
The competition to replace the long-standing Beretta M9 standard had already been opened to weapons of different calibers, opening the door to .40 and .45 caliber handguns. Russell noted the complexity of the different variables that come into play.
For example a larger round means more bullet mass and more gun powder, both of which would give it more power. But that can also damage accuracy, with more recoil forcing a shooter to spend more time reacquiring the target.
"It's about better performance than what we currently have, which includes the shootability," Russell said. "You can't just isolate one variable (as more important than the other)."
"We want them to produce the best system that meets the requirement."
The FBI switched from 9 mm to .40 caliber after a deadly 1986 shootout in Miami in which the shooters managed to keep fighting after being hit. The FBI is in the process of switching back to 9 mm – though the federal law enforcement agency uses hollow point bullets.
The Hague Convention of 1899 included a declaration banning bullets that "expand or flatten easily in the human body." The premise of the convention – designed well before World War I – was that the bullets caused unnecessary and therefore inhumane injury unrelated to stopping a combatant from continuing to fight. The U.S. did not to sign onto that rule.
The British – its most fierce opponent in 1899 because of its use of flattening "dum-dum" bullets, most frequently on the frontier of British India – later signed on in the Hague Convention of 1907.
