A class 1 stoppage is one a Soldier can clear within 10 seconds; a class 2 stoppage is one a Soldier can clear, but requires more than 10 seconds; and, class 3 is a stoppage that requires an armorer to clear."
DID will simply point out that 10 seconds can be a rather fatally long time when people are shooting at you, and at your friends. So, what happens when the Extreme Dust Test III stoppages are broken out by weapon?
The M4 Carbine is the Army's existing weapon.
- 882 jams, 1 jam every 68 rounds, again using heavy lubrication. In addition all 10 of the M4 barrels needed to be replaced, and a number of their parts were replaced during the test. None of the cold hammer forged HK416 and XM-8 barrels needed replacement.
The HK416 is a modified M4 carbine, which can be and has been converted from existing rifles. Used by US Special Forces.
- 233 jams, 1 jam every 257 rounds, 3.77x more reliable than the M4.
FN SCAR is US special Forces' new weapon, designed by SOSOCM. It just went into production in late 2007.
- 226 jams, 1 jam every 265 rounds, 3.85x more reliable than the M4
XM-8 is a developmental rifle. It's an advanced version of HK's G36, a rifle in wide use by many NATO armies. The US Army cancelled the XM-8 weapons family 2 years ago.
- 127 jams, I jam every 472 rounds, 6.95x more reliable than the M4.
The failure of M4 barrels at 6,000 rounds confirms SOCOM objections that date back to the Feb 23/01 report "M4A1 5.56mm Carbine and Related Systems Deficiencies and Solutions," which ended up concluding that "M4A1 Carbine… does not meet the requirements of SOF." The barrel replacement also increases the rifle's life cycle costs when compared with the 10,000 round advertised barrel life, as additional barrels are sold to the Army for $240 each. A longer, heavier M16 barrel, which is a competed production weapon, cost $100 by comparison. While the dust test is indeed an extreme test, the 10,000 round requirement is under "all conditions" – not just ideal conditions.
Dec 18/07: The US Army publishes "M-4 Carbine Has High Soldier Confidence Despite Test." Not exactly a headline to inspire confidence, as the Army acknowledges that the M4 Carbine finished last among the 4 contenders – but amazingly, asserts that the rifle is just fine and shows no interest in buying even the HK416's parts swap-out into the existing M4:
"After being exposed to the heavy dusting, 10 of each weapon fired 6,000 rounds apiece. They were fired in 50 120-round cycles. Each was then wiped and re-lubricated at the 600 round mark. After 1,200 rounds were fired from each weapon, they were fully cleaned and re-lubricated… "While the M-4 finished fourth out of four, 98 percent of all the rounds fired from it went off down range as they were supposed to do," Brig. Gen. [Mark] Brown [commander of Program Executive Office Soldier and the Natick Soldier Systems Center] said. "However, the three other candidates did perform better at about a 99 percent rate or better, which is a mathematically statistically significant difference, but not an operationally statistical difference.".... The Army has put an option on an existing contract for 64,450 M4s, according to the general."
"A mathematically statistically significant difference, but not an operationally statistical difference." Perhaps the US Army could put that on their recruiting posters, next to a picture of a jammed rifle.