A New Cartridge For The Army?
Defense contractor Textron just unveiled a new rifle at the Modern Day Marine conference. Designed to use so-called “telescoped” ammunition, the new rifle promises a harder-hitting, lighter bullet for America’s ground troops to fire. Whether the U.S. military is ready to embrace all the change a new rifle and ammunition would bring remains to be seen.
Traditional bullet cartridges have a bullet seated roughly halfway inside a brass shell casing, with gunpowder inside the casing. By contrast, the new rifle uses a 6.5-millimeter polymer-cased telescoped bullet. Telescoped rounds feature a bullet completely encased in a polymer shell, like a shotgun, with gunpowder surrounding the bullet in the shell.
The result is a cartridge that doesn’t use brass, a considerable savings in weight. According the Kit Up! blog, telescoped ammunition is about 40 percent lighter than traditional ammunition. Textron could have channeled this weight savings into making lighter ammunition, but instead it chose to make new ammunition that packs a bigger punch. The rifle—and 20 rounds of ammunition—weighs a total of 9.7 pounds. By contrast, the standard M4A1 (pictured above) and 30 rounds of ammunition weigh 8.74 pounds.
Textron claims the new 6.5-millimeter round has 300 percent more energy than the standard U.S. Army bullet, the M855A1. That translates into greater knockdown power against human targets, more armor penetration, and longer range. A heavier bullet and more energy would solve a persistent complaint about the U.S. Army’s M4A1 carbine—that the smaller 5.56-millimeter bullet often requires multiple hits to incapacitate a target and it lacks the range to make accurate long-range shots. The latter has been a particular complaint in Afghanistan, where long-range engagements are common.
Textron’s rifle is a gas-operated, piston-driven rifle that has many familiar features drawn from the M4A1, including a charging handle and gas block. It features military-standard rails for the attachment of devices such as flashlights and lasers, and what appears to be Advanced Armament Corporation flash hider. The front and rear sights, pistol grip, and buttstock are all from firearm accessory manufacturer Magpul.
Well, whatever. It isn’t clear why the round has more energy. That could be due to greater bullet mass or bullet velocity or a combination of both. The mass of the bullet, grains of powder, muzzle velocity and other information are left unsaid.
If it has a higher muzzle velocity, then that will come with side effects such as shooting the barrel rifling out sooner than with the M4. I could be wrong and commenters may correct me, but my understanding is that the guys who shoot .243 in competition have to be sponsored due to having to change barrels out so frequently (at 4000 FPS the barrels are good for only several hundred rounds and then they have to be replaced to maintain accuracy).
If the bullet has more mass along with more powder to propel it the same velocity as the 5.56 mm (~ 3150 FPS), then it has more recoil which will cause a change in the ability of the shooter to retain sight picture (a huge advantage of the low recoil 5.56 mm). You don’t get something for nothing.
The 5.56 mm round has ended the lives of many enemy fighters in Vietnam, Iraq and Afghanistan. It has a long history of being a highly proficient round, and most complaints about its effectiveness are due to the inability to properly utilize it.
I’ll stick with the Stoner design, thank you. If the new cartridge is worth anything, it’ll have to prove its mettle in battle.

