SOST: A Way Forward in Contemporary Understanding of the 1899 Hague Declaration on Expanding Bullets

SOST: A Way Forward in Contemporary Understanding of the 1899 Hague Declaration on Expanding Bullets


Military adoption of Spitzer (pointed) tip bullets began in 1898 with the French solid brass boat-tailed Balle D.  Germany introduced its 7.9mm S Patrone (800 mps at 25 meters) in 1905.  The United States followed suit with its “Cartridge, Ball, Cal. 30, Model of 1906,” firing a 150 gr. Spitzer bullet at 820 m/s.  The United Kingdom adopted its 160-grain .303 inch Mk VI RL 15572.G(1) with a muzzle velocity of 744 m/s in 1909.  Spitzer projectiles enabled increased velocity and a flatter trajectory, providing increased accuracy at longer ranges.  Terminal effects can be influenced by projectile yaw angle on impact.  If the yaw angle is shallow, the neck length (distance before 90 degree yaw) is long.  As impact yaw increases, the neck length decreases, that is, the projectile yaws sooner.  Military rifle bullets seldom “tumble,” suggesting a projectile turning end-over-end through 360 degrees.  Owing to its center of gravity, a rifle projectile may turn 180 degrees in soft tissue to a base-forward attitude.  Early yaw at higher velocities, that is, generally velocities at less than 200 meters, places stress on the jacket that may result in projectile fragmentation in soft tissue.  A century of military use of Spitzer bullets illustrates their value and acceptance by governments of fragmentation in soft tissue.

Introduction of Caliber 5.56x45mm Weapons
U.S. introduction of the 5.56x45mm M16 rifle during its war in Viet Nam resurrected questions as to application of the 1899 Hague Declaration Concerning Expanding Bullets for various reasons: (a) opposition by some nations to U.S. and allied (Australia, South Korea, Thailand, and The Philippines) involvement in that conflict; (b) a self-inflicted wound by M16 proponents inflating terminal ballistics effectiveness through the “tumbling action (sic.) of the .223 caliber ammunition,” and (c) opposition for economic reasons by some governments in the process of developing their own smaller-caliber weapon system (in Sweden’s case, its 4.5x26R MKR experimental assault rifle).

These challenges came to the fore in diplomatic conferences convened in Geneva between 1974 and 1980 and follow-on international meetings of experts from 1980 to 2003.  (The author served as the senior U.S. representative through the three decades of negotiations and experts’ discussions.)  Proposals for a new law of war treaty to “update the 1899 Hague Declaration Concerning Expanding Ammunition,” as its proponents described it, received little interest much less support.  In most cases, the only delegations participating in meetings of the Small Arms Working Group were two representatives each from Sweden and the U.S. (out of more than seventy government delegations).

A Swedish proposal to limit rifle bullet fragmentation prohibited “high velocity” weapons.  It defined “high velocity” just above the 710 meters per second velocity of the Russian 7.62x39mm when fired from the AK47/AKM while prohibiting the NATO 7.62x51mm cartridge (837 meters per second) and, in particular, the 5.56x45mm SS109 (915 meters per second) NATO was about to adopt.  The Swedish-proposed reduction in velocity would have had range-limiting consequences.  The proposal received no support from NATO nations, the Soviet Union, the latter in the process of fielding its 5.45x39mm (900 meters per second) AK74, or other delegations.  This was a resounding statement that governments did not regard military rifle bullet fragmentation as objectionable, much less prohibited by the 1899 Hague Declaration.

These international discussions acknowledged the historical practice and accepted the legality of military rifle-caliber bullets fragmenting when striking the human body at 200 meters or less.  A Russian delegate, wounded eleven times in World War II, pointed out that if there is no impact yaw and the projectile does not strike a hard object, such as bone, it will pass through the body with limited damage (usually the diameter of the projectile), often failing to render the targeted combatant hors de combat, that is, out of the battle and no longer posing a threat to opposing forces.  As a consequence he or she could be shot at repeatedly until rendered hors de combat through additional wounds, death, or the wounded soldier’s unequivocal indication of a desire to surrender.  For reasons previously noted, delegations expressed skepticism as to whether small caliber wounds rose to the level of “unnecessary suffering” in light of other wounding mechanisms on the modern battlefield.  Conference results reflected this through emphasis on new protocols regulating mines and incendiary weapons for the protection of the civilian population, but not limiting their employment against combatants.  Finally, governments were not inclined to engage in major investments of defense funds to exchange existing small arms ammunition inventories for non-fragmenting, potentially less effective projectiles.

On October 28, 1980, the North Atlantic Treaty Organization adopted 5.56x45mm as its second small caliber rifle cartridge.  In contrast to the 55-grain U.S. M193 bullet fired from a M16 rifle with 1-in-12 twist barrel, NATO adopted the Belgian (Fabrique Nationale Herstal [FN]) designed 62-grain SS109 (US M855) fired in a 1-in-7 twist barrel.  A FN official attending a 1982 Wound Ballistics Symposium in Goteborg, Sweden, suggested the SS109 projectile was “more humane” than the M193.  Test shots fired into ten percent ordnance gelatin identified no discernable distinction between M193 and M855 terminal ballistics.

In addition to widespread acceptance that military rifle projectile fragmentation in soft tissue is common and not inconsistent with the 1899 Hague Declaration’s prohibition of “bullets which expand or flatten easily in the human body,” international discussions led to development of modern wound ballistics testing procedures pioneered by Martin L. Fackler, MD, during his years as the founder and director of the wound ballistics laboratory at the Letterman Army Institute of Research (1981-1991).  His procedure of firing into ten per cent ordnance gelatin ((25x25x50 cm blocks of a 10% weight construction shot at 4 degrees C) was adopted by governments and agencies, such as the Federal Bureau of Investigation’s Ballistics Research Facility.  The procedures established by Dr. Fackler provide comparative terminal ballistics data for the distance at which tests are performed.

International discussions offered conclusions paralleling the U.S. position, that is, that military bullet legality is based on the prohibition of weapons or munitions intended to cause superfluous injury, that is, a determination that injury to combatants is clearly excessive when weighed against the stated military requirement and other relevant factors, including consideration of historic and contemporary wounding mechanisms and risk to the civilian population.  For example, the keynote speaker at an international wound ballistics conference in Thun, Switzerland, in 2001, Sir Christopher Greenwood, now a Member of the International Court of Justice, commented that “unnecessary suffering” acknowledges there is such a thing as “necessary suffering” in military operations.  Protecting innocent civilian lives may weigh in favor of small arms ammunition causing greater harm to combatants or terrorists than standard ball ammunition.  Sir Christopher’s analysis is borne out in RUAG Ammotec’s Swiss P Styx Action (5.56×45, 7.62×51, .300 Winchester Magnun, and .338 Lapua Magnum) ammunition for law enforcement, military, and other special units, for example.  The contemporary combat environment, including urban combat operations, along with increased demand for reducing risk to innocent civilians, constitute key factors in ammunition development and selection that did not exist when the 1899 Hague Declaration was drafted.

In defining the international legal offense of employing prohibited bullets, the following elements of the offense were established by the International Criminal Court (ICC):

  1. The perpetrator employed certain bullets.
  2. The bullets were such that their use violates the international law of armed conflict because they expand or flatten easily in the human body.
  3. The perpetrator was aware that the nature of the bullets was such that their employment would uselessly aggravate suffering or the wounding effect.
  4. The conduct took place in the context of and was associated with an international armed conflict.
  5. The perpetrator was aware of factual circumstances that established the existence of an armed conflict.

The ICC elements reinforce the U.S. position that legality of a military small arms projectile is determined by balancing the military requirement for a projectile against “uselessly aggravate[d] suffering.”  This coincides with results from the three decades of international discussions by government experts.  The elements require specific intent (mens rea) to employ small arms munitions against combatants to “uselessly aggravate suffering” for there to be a criminal offense.  “Uselessly aggravate” means the injury must be excessive when balanced against military and other requirements for the projectile.  Such a review necessitates consideration of historical practice with respect to what nations have accepted as lawful.

In 2010 the International Criminal Court extended its jurisdiction with respect to this offense to non-international armed conflicts.  Statements by government delegations that the extension of jurisdiction did not limit use of expanding ammunition (including hollow point ammunition) by law enforcement agencies or military counterterrorist units met with no objection from other participating delegations, re-enforcing Justice Greenwood’s 2001 analysis.

Evolution of and Requirements for SOST Ammunition
Requirements for SOST ammunition evolved from several sources or areas of experience.  A major reason for SOST development was to respond to field experience in global military operations since 2001.  The M855 was developed for U.S. and other NATO forces, the former armed with 20-inch barreled M16 rifles, to face Warsaw Pact forces on a linear battlefield largely devoid of civilians.  U.S. Special Operations Forces (SOF) moved from the M16A1with 20-inch barrel to the M4A1 carbine with 14.5-inch barrel (in some cases, shorter barrels) to meet contemporary threats. The shorter barrel resulted in an inability to defeat intermediate barriers, increased muzzle flash, and reduced effective range. A 2007 U.S. Army small arms capabilities study determined that the M855 did not meet contemporary operational requirements.

SOST objectives were:

  • Design 5.56x45mm and 7.62x51mm cartridges for use in carbine-length barrels;
  • Reduce muzzle flash;
  • Improve performance against, and targets behind, intermediate barriers, such as automobile glass or doors;
  • Improve accuracy over (e.g.) the 3 to 5 minute of angle M855;
  • Final product cost to be as close as possible to current ball cartridge (M855 in 5.56x45mm, M80 in 7.62×51);
  • Improve internal, external, and terminal ballistic performance consistency; and
  • Improve propellant temperature stability over current ball cartridge in each caliber.
  • An additional requirement for the 7.62x51mm cartridge was recoil reduction over the M80 ball.

The 5.56x45mm cartridge consists of a standard lead styphnate #41 staked military primer, standard M855 military specification cartridge case, and a 62-grain boat tail open tip match (OTM) projectile which has a typical lead core in front and a solid copper shank from the cannelure to the projectile base.  The propellant was developed for optimum performance when fired in 14-inch barrel carbines while maintaining full compatibility with all currently fielded U.S. 5.56x45mm weapon systems.

The 7.62x51mm consists of a standard lead styphnate No. 34 military primer, staked, standard M80 military specification cartridge case, and a flat base 130-grain OTM projectile with a typical lead core in the front, and a solid copper shank from the cannelure to the projectile base.  The propellant was developed for optimum performance when fired in a 16.5-inch barrel while maintaining full compatibility with all existing 7.62x51mm NATO weapon systems.  The 130-grain projectile is lighter than the M80 ball, allowing for increased muzzle velocity while enabling a ten to fifteen per cent reduction in recoil.

The solid shank in each caliber projectile provides substantial increased performance against intermediate barriers, while the front portion of each projectile performs like other OTM projectiles, improving accuracy vis-à-vis standard ball ammunition.  M855 ball has been shown to have inconsistent terminal ballistics, in part owing to its sensitivity to impact yaw experienced in M16 rifles and M4A1 carbines.  The SOST design enhances the projectile’s ability to be “blind to barriers” by limiting fragmentation of the projectile to the area ahead of the solid base while also being blind to impact yaw, that is, it is not yaw dependent.  This characteristic ensures greater consistency in terminal ballistics against enemy combatants whether wearing or not wearing body armor.  On impact with bare gelatin, the nose of the projectile is damaged and fragments into smaller pieces.  The solid copper base continues in a somewhat straight line.  Projectiles in each caliber routinely penetrated in excess of eighteen inches.  As can be expected, the 7.62×51 SOST exhibits a deeper overall penetration and a larger temporary cavity than its 5.56×45 counterpart.  The typical wound profile in each caliber is a neck length that is short (<1.25”) or non-existent.  The 5.56x45mm SOST wound profile differs from the M855 in its consistency of performance at close range, consistency of penetration path following intended shot line, increased depth of penetration, and reduced fragmentation vis-à-vis the 5.56x45mm NATO SS109.

Compared with the 3 to 5 minute-of-angle accuracy of the M855 when fired from a M4A1, 5.56 SOST ammunition shot in a 14-inch Fabrique Nationale SCAR (Light) carbine produced average extreme spreads of 1.71 minutes of angle at 300 yards and 1.67 minutes of angle at 600 yards.

Beginning in 1974, the U.S. Department of Defense has required a legal review of all new weapons and munitions to ensure their compliance with the international legal obligations of the United States, including the law of war.  In the course of its development, SOST ammunition underwent two such legal reviews.  A favorable legal review was provided by the Office of General Counsel, Department of Defense, in 2009, in conjunction with consideration of the Special Operations Forces Combat Assault Rifle.  That review included coordination with the Offices of the Judge Advocates General of the Army, Navy, and Air Force, and the Staff Judge Advocate to the Commandant of the Marine Corps.  The following year the Office of the Judge Advocate of the Navy, in coordination with those same offices, provided a second positive legal review.  Each legal review included observation by reviewing officers of wound ballistics testing performed at the Ballistics Research Facility, Federal Bureau of Investigation Academy, Quantico, Virginia, a requirement for legal review of all U.S. military small arms ammunition.  Overall, SOST terminal ballistics were comparable to existing military small arms projectiles.

The lengthy history relating to the 1899 Hague Declaration Concerning Expanding Bullets and its interpretation by governments identifies factors considered in military small arms ammunition development.  Much has been discovered (hopefully learned) as to progressions in military small arms ammunition development, historical practice since 1899, the medical aspect of wound ballistics, three decades of recent diplomatic discussions, and consideration of military requirements based upon experience in the combat environment of the past decade.  The SOST round was developed based upon this knowledge and military requirements.  It offers clarification as to the intent behind the 1899 Hague Declaration and its interpretation in today’s world.