2007 Winchester NATO 5.56 M855 SS109 AP Penetrator Sealed in "M2A1 Level A Pack" can. Same ammo our military is using right now. With the level A pack, four point protector boxes fit in a bandoleer and seven bandoleers in an M2A1 can (28 boxes and 840 rounds per can); two cans then fit in a wirebound crate (1,680 rounds per crate); This is not factory seconds M855 in WWB (Winchester White Box). May never see Level A Pack for sale again............. 840 rounds in one sealed can, $675 cash only. Todd Todd_sealy@hotmail.com How can you tell real M855 ammo, look for the NATO head stamp - see example of 1967 WCC Winchester from Vietnam. History of M855 and M193 - why does M855 cost so much M193 NATO 5.56mm ball cartridge: Introduced in 1964, the M193 was the original 5.56mm cartridge designed for use in the M-16 rifle with a 1 in 12 rifled barrel twist, it has been replaced by the heavier M855 cartridge. The M193 can be identified by its unpainted FMJ tip. M855 NATO 5.56mm ball cartridge: Introduced as a replacement for the M193 cartridge, the M855fires a heavier projectile with greater accuracy. While the cartridge was designed to be fired from the newer heavy barreled M-16A2 assault rifle and M-4 carbine (each of which has a 1 in 7 twist barrel) it may be fired out of older M-16 models without severe degradation of accuracy. The M855 can be identified by its green painted tip. M855 is a newer round developed in the late 1970s by Fabrique Nationale (FN) of Belgium. FN was developing a new 5.56mm belt-fed machine gun they called the "Minimi" (Mini-Machinegun) for entry into the US military's Squad Automatic Weapon (SAW) program. The SAW was to augment, and in many cases replace, the 7.62×51mm M60 made by Saco Defense (now part of the General Dynamics Armament Division). Because there was a lot of resistance to giving up larger, longer-range round of the M60, FN focused on making the SAW perform better at longer ranges than existing 5.56 platforms (i.e., the M16). They did this primarily by developing new bullets: the SS-109 "ball" round and the L-110 tracer. The SS-109 bullet uses a "compound" core, with a lead base topped by a steel penetrator, all covered in a gilding-metal (copper alloy) jacket. The SS-109 bullet was proven to have better penetration of the then-current-issue steel helmet at 600m than the M80 "ball" ammo fired by the M60. The M80 ammo was not able to penetrate both sides of the helmet at that distance; the SS-109 bullet could.