SOURCE: Jim Shepherd's Shooting Wire The United States Marine Corps is once again breaking from the norm when it comes to their equipment. This latest break is in their 5.56 ammunition. This latest change means the Corps will be using an "open-tipped" round as opposed to the heretofore standard M855 ball round. The New 5.56 SOST a "couple million" are already in theatre, and more is on the way. So what's the advantage? The new SOST round (Special Operations Science and Technology) is a more deadly and more accurate round - especially when fired in the Corps' shorter barreled rifles. Initially, the SOST was only cleared for use by the Special Operations Command troops (SOCOM) with their Special Operations Force Combat Assault Rifle (the SCAR). This new round is essentially an open-tip round, similar to sniper ammunition. It's also supposed to be "barrier blind" - staying on target better than M855s after penetrating windshields, car doors and other objects. It's also reported to stay on target longer when fired and deliver increased stopping power through "consistent, rapid fragmentation which shortens the time required to cause incapacitation of enemy combatants". In other words, the new SOST round is, ala-the high-tech hunting ammunitions which have existed for some time to quickly deliver the knockout punch to an enemy. According to reports in the Marine Corps Times, the round at 62-grains, weighs pretty much the same as other NATO rounds, and have a lead core with a copper shank. Speculation is they are a variation of the Federal Trophy Bonded Bear Claw round. Originally, the rounds were purchased for use in the SCAR, but its performances in penetration, accuracy and decreased muzzle flash convince the Corps to make it available to their general troops as well. The standard M855 round has been around more than three decades and has long been the focus of complaints regarding its overall effectiveness. Today, troops quietly criticize the round as lacking enough "oomph" to stop typical adversaries. The Pentagon first asked for an improved round in 2006. Despite determining the M855 no longer was meeting acceptable USMC performance standards, there are no plans to remove the millions of existing rounds from inventory. In the document clearing the use of the new SOST round, the director of the Navy Department International and Operational Law Division recommends the use of the new SOST-formally known as "MK318 MOD 0 enhanced 5.56 ammunition". "Based on the significantly improved performance of the MK318 MOD 0 over the M855 against virtually every anticipated target array in Afghanistan and similar combat environments where increased accuracy," Crisfield wrote, "better effects behind automobile glass and doors, consistent terminal performance and reduced muzzle flash are critical to mission accomplishment, USMC would treat the MK318 MOD 0 as its new 5.56mm standard issue cartridge." It will be issued to both the short-barreled M4 carrying troops - the original users, and field forces carrying the full-length M16A4. There's only one weapon that won't be using the new round - the M249 Squad Automatic Weapon, and that's temporary. Currently, the round isn't being produced in the linked version needed for the SAW. Having cleared the international legal hurdles over using an "open tipped" ammunition, the USMC appears poised to go into combat with a more lethal round that is specifically suited to meet the needs of today's non-traditional combat.