This was posted in GD by another member of arfcom and I got the link from him.
I know its long, but its worth it
Some press accounts have placed blame for M4 carbine malfunctions at the Battle of Wanat, Afghanistan, squarely on the weapon's manufacturer. In fact, other factors could have led to the disaster there.
On the morning of 13 July 2008, 49 Americans, including 40 paratroopers from Captain Matthew Myer's Chosen Few Company of the 2nd Battalion, 503rd Airborne Infantry, six combat engineers, and three Marine embedded tactical trainers were defending Combat Outpost (COP) Kahler near Wanat in Nuristan Province. Also involved were 24 Afghan National Army soldiers from the 3rd Kandak [Battalion], 2nd Brigade, 201st Corps. Suddenly, a deadly wave of intense small-arms fire and rocket-propelled grenades struck the small and exposed operating base.1
As many as 200 insurgents—core Afghan-centric and foreign takfiri fighters supported by numerous local combatants—crept, many barefoot, to within meters of the American positions. The insurgents quickly debilitated the unit's heavy weapons, then, in a coordinated effort, suppressed Kahler and simultaneously moved to isolate the defenders of Observation Post (OP) Topside, three fighting positions that had been situated on a prominent knoll east of COP Kahler proper.
Only the timely arrival of support—including American AH-64 Apache attack helicopters and field artillery—prevented the complete destruction of COP Kahler.2 Yet the outcome was tragic enough: nine U.S. Soldiers died, and a further 27 were wounded, making that day one of the bloodiest of the war and prompting The New York Times to describe the four-hour Battle of Wanat as "the 'Black Hawk Down' of Afghanistan."3
More than a year after the battle, historian Douglas R. Cubbison of the U.S. Army's Combat Studies Institute released a 248-page draft Occasional Paper in an attempt to sort out what went wrong.
The American and Afghan troops outnumbered there two years ago were plagued by numerous weapon stoppages. Beyond all the clamor, just how reliable is the M4?
Immediately after the release of the Army's Occasional Paper, press reports seized on Soldiers' accounts of weapon stoppages detailed in it. The Times reported that "Soldiers who survived the battle described how their automatic weapons turned white hot and jammed from nonstop firing."4 A November 2009 Defense News story also cited reports of weapon stoppages, but went further, attempting to connect the deaths of Soldiers in the battle to the enduring debate over the reliability and lethality of the military's primary infantry weapon, the M4 carbine.
Since its introduction with U.S. forces during the Vietnam War, the M16 rifle and its offspring, including the M4, have been the subject of some controversy, especially related to reports of the weapons' reliability in combat. Initial reports from Vietnam indicated a high incidence of stoppages. These were in fact directly related to the Army's initial decision to alter the ammunition's propellant from military specifications (mil-specs) and to dispense with chrome plating the M16's chamber—an improvement that had become a standard feature of all U.S. military small arms since World War II.
Both decisions led to premature corrosion of the chamber and ultimately to stoppages. Upgrades, including those that improved the manufacturing process and design of the weapon's buffer, bolt, trigger components, and chamber, which would receive a chrome lining, resulted in a much superior M16A1. Troops issued the M16A1 in 1969 and later rarely complained about their weapons. One Marine rifleman did complain in a 1967 letter to his family following the battle for Hills 881 and 861 above Khe Sanh: "We left with 72 men in our platoon and came back with 19. Believe it or not, you know what killed most of us? Our own rifles. Practically every one of our dead was found with his [M16] torn down next to him where he had been trying to fix it."5
Not mentioned in the letter was the fact that many of the Marines who fought at Khe Sanh had been issued their M16s only days before the action and probably were unfamiliar with them. Also worth mentioning is the fact that the M16 of four decades ago is not the same weapon as the M4 in service in Iraq and Afghanistan today. Enhancements made to the original design have substantially improved the weapon's reliability, so much so that commanders often praise the M4. At the 2006 Infantry War Fighting Conference, Major General Walter Wojdakowski, commanding general, U.S. Army Infantry Center & School, called the M4 "one of many success stories in combat operations in Iraq and Afghanistan."6
Yet troops outnumbered at Wanat, like those described in the Khe Sanh account 41 years before, were still plagued by numerous weapon stoppages. Studies conducted by the Army, by independent research institutions, and by Colt itself offer some indication of the cause. In particular, they provide some possible explanations for the numerous stoppages suffered by Wanat's defenders.
The Army's draft Occasional Paper states that to maintain fire parity with their attackers, the Chosen Few Company soldiers "were firing their weapons 'cyclic,' on full automatic at the highest possible rates of fire."7 For this reason, the paper concludes, some Soldiers experienced stoppages.
Staff Sergeant Erich Phillips, manning the 120-mm mortar, recalled that during the engagement his "M4 quit firing and would no longer charge when [he] tried to correct the malfunction." An engineer specialist who loaded for Phillips recalled that, "Staff Sergeant Phillips poured out fire," going "through three rifles using them until they jammed."8 Specialist Chris McKaig, defending OP Topside, also experienced problems with his M4. "My weapon was overheating," he recalled. "I had shot about 12 magazines by this point already and it had only been about a half hour or so into the fight. I couldn't charge my weapon and put another round in because it was too hot, so I got mad and threw my weapon down."9
The CNA Study
The subject of weapon stoppages during engagements in Iraq and Afghanistan figured prominently in a 2006 formal independent study conducted by the Center for Naval Analyses (CNA) at the behest of the U.S. Army's Project Manager, Soldier Weapons (PMSW), located at Picatinny Arsenal, New Jersey. The study, Soldier Perspectives on Small Arms in Combat, is based on a survey of 2,607 Soldiers, a sampling of active-duty Army and Army Reserve personnel (70 percent), and National Guard personnel (30 percent), who had returned from Iraq or Afghanistan within the 12 months prior to the study and had engaged in at least one firefight using an M9, M4, M16 (A2 or A4), or an M249 during their last deployment.10 No special operations or Marine Corps personnel participated in the study. Its findings suggest weapon stoppages are not uncommon during combat in both theaters.
Respondents were chosen to parallel as closely as possible the actual demographics of Soldiers in combat in Iraq and Afghanistan. Overwhelmingly, 95 percent of respondents had just returned from deployments in Iraq. Most (80 percent) were E-4s, E-5s, or E-6s; most (61 percent) had served for one to five years; most (77 percent) had qualified as sharpshooter or expert; and most (84 percent) had participated in one to five engagements during their deployments, though 15 percent had fought in more, and 27 respondents each indicated they had survived more than 50 engagements. If one attempted to describe the average respondent to the CNA survey, one might say he was a Soldier in the Regular Army, an E-5 with a little over six years in service and a recent tour in Iraq during which he fought in five engagements. Armed with an M4, he is a sharpshooter.11
The study did not capture specific information regarding the numbers of engagements each respondent had participated in; instead, it asked respondents to indicate the number of engagements in which they fought within a range of choices: 1-5, 6-15, 16-30, 31-50, or More than 50. When interpreting information regarding the frequency of weapon stoppages, this becomes important. Reflective of the 25 percent of Soldiers who were issued the M4 in the actual population at the time of the study, 917 respondents to the survey—roughly 35 percent—carried the M4 carbine on their last deployment.12
Of these respondents, 173, some 19 percent, reported they had experienced a weapon stoppage during an engagement. And of that number, 31 reported experiencing a large-impact stoppage, meaning that he "was unable to engage the target with that weapon during a significant portion of or the entire firefight after performing immediate or remedial action to clear the stoppage."13
Given the fact that the study contains no specific data regarding the numbers of engagements fought, incidences of M4 stoppages must be depicted as occurring at a frequency within the low-high range of engagements reported: 2,562 to 7,281 or more. Thus, the CNA study suggests that M4 weapon stoppages occurred during engagements 6.75 to 2.37 percent (or less) of the time, and that large-impact stoppages occurred 1.21 to 0.42 percent (or less) of the time. While no specific information is available describing the exact cause of each stoppage reported, in general terms, the study indicates that frequency of stoppages is impacted by full-automatic fire and several other factors.
Full-Automatic Fire and Weapon Stoppages
At Wanat, the weapons were pushed to their limits and beyond. In the Combat Studies Institute's paper, historian Cubbison attributed the weapon stoppages experienced by Wanat's defenders to their necessity to fire their M4 carbines at sustained high cyclic rates. This conclusion is supported by the CNA study, which revealed that Soldiers firing weapons on full-automatic doubled their probability of experiencing a stoppage.14
In a 21 October 2009 letter from Colt Defense LLC's executive vice president, retired Marine Major General James R. Battaglini, to Army Colonel Douglas Tamilio, project manager, Soldier Weapons, General Battaglini concludes that, finding themselves "under attack by a numerically superior Anti Coalition Militia (ACM) force conducting well planned attacks with overwhelming firepower," Soldiers at Wanat used their weapons "in excess of their cyclic rates of fire."
The M4 carbine was born of the 1965-vintage Colt CAR-15 and XM177/XM177E2 carbines and the U.S. government's interest in procuring "a redesigned and upgraded variation of the M16A2 weapon system," which could fire the new M855 5.56x45-mm NATO cartridge.15 After several meetings with government officials beginning in September 1984, Colt received a procurement contract on 12 June 1985 to provide 40 XM4 carbines for testing and evaluation.
The weapons that resulted from this program, those that through development would become known as the M4 and M4A1 carbines, were initially intended to be used by rear-echelon Soldiers and others who required only more firepower than an ordinary sidearm. However, "by the time the M4 and M4A1 carbines went into production a decade later in 1994, the end users had become frontline fighting units such as the SEALs, Special Forces, and Airborne Divisions."16
The original emphasis the government had placed on parts commonality between the new carbine and the M16A2 rifle had shifted to performance. Since that time, numerous and substantial improvements have been made to the M4 and M4A1, including strengthening the bolt, extractor, and extractor spring, resurfacing the chamber, and, in 2000, the introduction by Colt of the R0921HB, a heavy-profile barrel M4A1.17
Rounds per Minute
According to U.S. Special Operations Command's SOPMOD (special operations peculiar modification) program office, "The current sustained rate of fire for the M4A1 Carbine is 15 rounds per minute and a maximum rate of 90 [rounds] per minute for short periods in an emergency."18 Firing the M4 carbine at cyclic rates of fire of 90 to 150 rounds per minute, "which is the rate of suppressive fire associated with machine guns" for prolonged periods leads to rapid heating of the barrel and possible failure.19
Tests conducted by both the Army and by Colt indicate that "exceeding the sustained rate of fire of 15 rounds per minute will result in the weapon 'cooking off' rounds after approximately 170 rounds have been fired." If the maximum rate of fire of 90 rounds per minute "is maintained for about 540 rounds, the barrel softens and gas starts to blow by the bullet, changing the sound and size of the muzzle blast." If the operator continues to fire the weapon, the barrel will begin to droop, and finally, at about 596 rounds, the barrel will burst.
While the current M4 configuration exceeds the Army's requirements for general issue, early in the M4 program, the Special Operations Command requested a heavier barrel profile to accommodate the rapid heating that accompanies special operations forces' (SOF) high firing schedules. The Army denied this request, however, because a heavy barrel would be incompatible with M203 installation and because it did not want to add a SOF-unique repair part to its inventory.20 In Fiscal Year 2001, Rock Island Arsenal (RIA) "responded to the distinct needs of SOF with the RIA heavy barrel."
The new heavy-profile barrel still allowed for the installation of the M203, but increased the rounds to cook off to 205 rounds, and the round count to barrel burst to 930. While the new heavy profile did not increase the service life of the barrel, it did provide SOF with, per its requirement document, an M4A1 having a limited light machine-gun capability, of a sort, as it requested.21 It should be noted that the requirement document did not define what this capability meant in the way of sustained fire (in numbers).
In any case, the rationale for such a capability is based on special operations forces' need to break contact with large enemy formations. The method SOFs employ to break contact in such engagements is to lay down an overwhelming burst of fire intended to suppress the enemy long enough for SOFs to slip away. It is for this reason these forces are working to develop a carbine capable of firing two 30-round bursts followed by at least 45 and up to 75 rounds per minute for 440 rounds without damaging the weapon.
Yet the M16/M4 was never designed to have this capability. In a 1967 TIME magazine article discussing the M16, the author marvels over "the M-16's maximum sustained rate of fire (up to 200 rounds a minute)." The quote provides some insight into the historical misconceptions about what the M16/M4 is, and what it isn't, and why many observers are disappointed in the 6-pound M4 when it fails to perform like a belt-fed light machine gun.
While suggesting that Soldiers maintain fire discipline as a means of preventing their weapons from overheating is a simple solution, when Soldiers are fighting for their lives under conditions extreme even for the battlefield-such as those that presented themselves to Wanat's defenders—such arguments lose their veracity.
According to officials at Colt, soon after the release of the Cubbison draft study, the Army contacted Colt, asking the company to "recommend any immediate options for the M4 carbine" that would increase its performance characteristics. Colt responded, recommending that the current Army contract requirement be modified by replacing the 3-round burst M4 with the fully automatic R0921HB/M4A1 and with the RIA heavy barrel, which would provide 1.7 times the sustained rate of fire as the M4.22
At Wanat, where firsthand accounts suggest that many defenders were firing their weapons at extremely high cyclic rates simply to prevent themselves from being overrun, it is possible that if they had been firing M4s with the RIA heavy-profile barrels instead of standard-issue weapons, they would have suffered fewer weapon stoppages. And yet some accounts, such as that of Specialist McKaig, who reported that his M4 overheated after firing 12 magazines—approximately 360 rounds—in a half hour's time (an overall rate of fire of only 12 rounds per minute; well within design specifications for the weapon) suggest either that Soldier's recollections are not accurate or that other factors may have led to weapon stoppages.
Other Possible Causes
The CNA study indicates that several other important factors contribute to an increased probability of experiencing a weapon stoppage, including cleaning and lubrication procedures (CLP), the attachment of weapon accessories, the weapons' magazines, and the possible use of rebuilt weapons. And these factors, in addition to sustained high cyclic rates of fire, may also have contributed as underlying causes of the weapon stoppages at Wanat.
"Maintenance regimens, including weapon cleaning and lubrication, have very little or no impact on . . . weapon stoppages" the report said. However, Soldiers who used dry lubricants in the maintenance of their M4s, rather than CLP, "decreased the probability of experiencing a stoppage by half."23 Soldiers reporting a high frequency of lubricant application (one or more times per day), particularly M16 users, were more likely to experience stoppages.24
Increased frequency in quick-wipedown weapon cleaning also increased the odds of experiencing a stoppage. This somewhat counterintuitive finding is most likely a result of Soldiers replacing fully disassembled cleanings with quicker and less effective methods. "9 to 10 percent of M4 and M16 users called for improvements in magazine quality. Soldiers stated that the [standard 30-round aluminum] magazines [issued] are easily dented during the course of normal use and carrying in theater, causing problems in ammunition feed from the magazine."25 Some combat veterans have said it's also critical to keep the magazines clean as well. The CNA report says, "Soldiers issued a cleaning kit with their weapons were one-third less likely to experience a stoppage than those not issued a cleaning kit."26
Surprisingly, more than one-third of all respondents to the CNA study indicated that they had not been issued cleaning kits with their weapons. The study indicates also that attaching accessories to the M4 significantly had an impact on stoppages, "regardless of how the accessories were attached." Soldiers who duct-taped and zip-corded accessories to their M4s "were two and three times [respectively] more likely to experience a stoppage."27 Finally, the report indicates, Soldiers issued rebuilt M4s are "3.5 times more likely to experience a stoppage."28
Dust Test 3
Beyond these potential causes are environmental factors. In a 10 December 2009 letter to Secretary of Defense Robert Gates and Chairman of the Joint Chiefs of Staff Admiral Mike Mullen, co-signed by Chairman of the House Committee on Armed Services Representative Ike Skelton (D-MO) and Chairman of the House Subcommittee on Readiness Representative Solomon Ortiz (D-TX), the congressmen raised the issue of the M4, citing their concerns that although the M4 "routinely rank[s] lower than other military weapons in testing, they are still being issued as the Army's weapon of choice."
What the congressmen seem to be referring to are the results of the U.S. Army Test and Evaluation Center's (ATEC) September-November 2007 Extreme Dust Test 3, which press reports leapt on as an indication of the M4's purported shortcomings. In the test, where ten sample M4s drawn from Army inventory competed against ten samples each of Heckler & Koch's HK416 and XM8 and Fabrique National's Mk16 SCAR, the weapons, with an initial coating of heavy lubrication applied, were placed in a dust chamber for 30 minutes and then fired to 120 rounds before being returned to the dust chamber for another half hour. This process was repeated to 600 rounds, at which point the weapons were wiped down and another coat of heavy lubrication was applied.29 Firing continued in this way to 6,000 rounds per weapon.
Raw test data made available to the press indicated that, collectively, M4s experienced 863 low-impact and 19 high-impact stoppages over a firing schedule of 60,000 rounds—the other weapons experienced significantly fewer stoppages—but ATEC's final report, which appeared in February 2008, noted that "M4 performance . . . was significantly different than in the previous extreme dust test in which it participated," and that a separate effort was under way to investigate the reasons.
According to officials at Colt, those reasons included the fact that six of the ten M4s drawn for the test did not meet the minimum rate of fire of 700 rounds-per-minute mandated under Mil-Spec IAW Mil-C-70599A(AR), which requires a cyclic rate of fire of 700 to 970 rounds-per-minute. The M4s used in Dust Test 3, delivered to the Army in June 2007, met mil-specs when delivered; however, together the ten drawn for the test from the U.S. Army inventory averaged only 694 rounds-per-minute.30 While performing comparably with the HK416, XM8, and Mk16 in all other respects, the M4 carbines used in the test experienced a large number of failure-to-feed and failure-to-extract stoppages.31 Colt says this is because of the sub-mil-spec rate-of-fire of the test weapons.
Colt also states that ATEC's testers were unfamiliar with the M4s' 3-round burst configuration which, depending on the position of the cam, will sometimes fire 1 round or a 2-round burst before firing a 3-round burst. This unfamiliarity, said Colt, led to single rounds and 2-round bursts being counted as stoppages. With the exception of the M4s, all other weapons tested were fully automatic with no 3-round burst provision. Further, Colt points out that the test itself did not meet Mil-Spec 810F and "was not repeatable."
In response to what Colt described as "the premature media reporting" of the raw test data, Program Executive Office Soldier suggested that Colt conduct its own extreme dust test. So Colt contracted a DOD-certified testing agency, Stork East-West Technology Corporation in Jupiter, Florida, to conduct its own dust test according to mil-spec guidelines. In this test of ten M4 carbines, which was conducted under a protocol identical to that used in Extreme Dust Test 3, only 111 stoppages were reported.
Where Are the M4s from Wanat?
Though possibly the result of numerous factors, the exact causes of the weapon stoppages suffered by Wanat's defenders are still unreported and perhaps unknown. According to General Battaglini, Colt requested that the U.S. Army provide the weapons recovered from Wanat so the manufacturer could test them to determine the precise causes of reported stoppages. So far, the Army has not obliged. When asked if the weapons from Wanat were recovered and tested, no officials at Project Manager, Soldier Weapons, the U.S. Army Test and Evaluation Center, U.S. Army Forces Command, or Central Command could or would respond. If the weapons have not yet been tested, nearly two years after the battle, the precise causes of stoppages may never be known.
Numerous media outlets have blamed the M4 for the death of Soldiers at Wanat, or continue to deride the weapon in favor of the commercial off-the-shelf products of Colt competitors-part of what Colt alleges to be a "concerted media campaign" led by writers at Army Times, Military.com, and others to promote the products of German firearms manufacturer Heckler & Koch. For now, however, the M4 carbine continues to be the U.S. Army's battlefield weapon of choice.
Questions asked about replacing the M4, which has a direct gas impingement operating system, with another carbine having a gas-piston system, have been repeatedly dismissed by the Army as offering no efficiency over the current system. In the late 1960s, in response to an official request, Colt provided the Army with its own gas-piston carbine, the model 703, which was tested and turned down as it offered no increase in reliability over the direct gas impingement operating system. Since then, other comparative evaluations and assessments have been completed supporting the Army's initial choice.
A December 2005 study conducted by the 10th Special Forces Group (Airborne), for example, which evaluated the HK416 and Colt's Close Quarters Battle-Receiver (CQB-R), concluded that CQB-R "out performed the HK416 in mechanical reliability."32 Other reports have rendered similar conclusions about other possible M4 replacements, including the XM8. The Army's own April 2008 Small Arms Capabilities-Based Assessment, carried out to support "a small arms acquisition strategy through 2015," did not fault the M4 carbine, but instead called for improvements in ammunition, sights, and optics.33
In January 2010, Project Manager, Soldier Weapons released a market survey outlining the Army's dual approach to both improvements of the M4 and moves being made toward a future carbine competition once the Joint Requirements Oversight Council approves the new requirement.34 In the meantime, the Army says, "We have what we need."35
A Leadership Failure
Though weapon stoppages certainly played some role in the outcome of the engagement, no disaster such as the one that occurred at Wanat is the result of a single failure, a single mistake. Rather, the Battle of Wanat was the result of a chain of tactical mistakes, lapses in judgment, failures to hold the human terrain, and failures of leadership. The Army acknowledged this, in part, in a CBS News report on 11 March 2010. Captain Matthew Myer, the Chosen Few company commander who was the senior American officer on the ground at Wanat and who was awarded a Silver Star for his heroism during the battle, along with Lieutenant Colonel William Ostlund, commander of the 2nd Battalion, 503rd Airborne Infantry, and Colonel Charles Preysler, commander of the 173rd Airborne Brigade, neither of whom were actually at the battle, received "career ending reprimands for failing to prepare adequate defenses [at Wanat] in the days leading up to the attack."36
To prevent future Wanats, military planners should make every effort to ensure American forces continue to receive the best and most appropriate weapons and equipment possible. More important perhaps, they also should make every effort to understand not only how the events immediately prior to the battle influenced its outcome, but how the many events that, together, comprised the much broader history of the American relationship with the people of Nuristan Province, those that lie at the heart of America's population-centered counterinsurgency strategy in the region, converged to form an outcome so tragic as the attack at Wanat.
1. Douglas R. Cubbison, , Occasional Paper: The Battle of Wanat-First Draft, (Fort Leavenworth, KS: Research and Publication Team, U.S. Army Combat Studies Institute, 2009), pp. 70, 73.
2. Ibid., p. 84.
3. Tom Shanker, "Report Cites Firefight as Lesson on Afghan War," The New York Times, 2 October 2009.
5. "Defense: Under Fire," TIME, 9 June 1967.
6. MGEN James R. Battaglini, USMC (Ret.), Letter to the Editor, Army Times, in response to Matthew Cox's article, "Better than M4, but you can't have one," Army Times, 1 March 2007. Remarks attributed to MGEN Walter Wojdakowski, Commander of the Infantry Center.
7. Cubbison, Occasional Paper, p. 115.
8. Ibid., p. 110.
9. Ibid., p. 125.
10. Sara M. Russell, Soldier Perspectives on Small Arms (CRM D0015259.A2 / Final) Alexandria, Virginia: Center for Naval Analyses (CNA): December 2006, p. 1.
11. Ibid., p. 11.
12. Ibid., pp. 10-11.
13. Ibid., pp. 17-1).
14. Cubbison, Occasional Paper, p. 115; and Russell, Soldier Perspectives, p. 23.
15. Christopher R. Bartocci, Black Rifle II: The M16 into the 21st Century (Cobourg, Ontario: Collector Grade Publications Inc., 2004), p. 67.
16. Ibid., p. 68.
17. Colt Defense, LLC. (2007). M4 Changes 1994-2007.
18. USSOCOM SOPMOD Program Office (USPO), (23 February 2001). M4A1 5.56mm Carbine and Related Systems Deficiencies and Solutions: Operational and Technical Study with Analysis of Alternatives (Draft, Version 6), (Crane, Indiana: Naval Surface Warfare Center USPO, 2001), p. 16.
19. Ibid., p. 15.
20. Ibid., p. 16.
21. Ibid., p. 14.
22. MGEN James R. Battaglini, USMC (Ret.). (21 October 2009). Letter to COL Douglas Tamilio, Project Manager, Soldier Weapons regarding "Battle of Wanat Historical Analysis," General Battaglini is the Executive Vice President of Colt Defense, LLC.Battaglini, 2009, p. 3.
23. Russell, Soldier Perspectives, p. 23.
24. Ibid., p. 22.
25. Ibid., p. 23.
26. Ibid., p. 22.
27. Ibid., p. 23.
29. Matthew Cox, "Changes to the M4?" Marine Corps Times, 14 January 2008, p. 12.
30. Colt Defense, LLC. (February 2008). Colt Data and Analysis of M4 Carbine Cyclic Rates of Fire for Colt Weapons Used in Dust Test #2 and #3: Competition and Test Control, p. 25.
31. U.S. Army Test and Evaluation Center (ATEC). System Assessment Reliability Performance of Select 5.56-mm. Excerpts provided by Colt Defense LLC, 2008, p. 2-2.
32. MSGT Kevin M. O'Connor, USA, AAR HK 416 Operations Testing and Assessment (Memorandum for Record), Department of the Army, 10th Special Forces Group (Airborne), Fort Carson, CO, p. 4.
33. Andrew Feickert, (2009, August 3). The Army's M-4 Carbine: Background ad Issues for Congress (RS22888). Congressional Research Service, 3 August 2009, p. 6.
34. Scott Gourley, "Army Shifts Modernization Focus to M4 Carbine Improvements," The Year in Defense, 8 April 2008.
35. Matthew Cox, "Army Acquires Rights to M4," Army Times, 6 July 2009.
36. David Martin, "Exclusive: Hero's Acts Faulted," CBS News, 11 March 2010.