E C M4 Review Assignment

This document is meant purely as a documentation tool and the institutions do not assume any liability for its contents

on the taking-up and pursuit of the business of Insurance and Reinsurance (Solvency II)


Having regard to the Treaty establishing the European Community, and in particular Article 47(2) and Article 55 thereof,

Having regard to the proposal from the Commission,

Having regard to the opinion of the European Economic and Social Committee (1),

After consulting the Committee of the Regions,

Acting in accordance with the procedure laid down in Article 251 of the Treaty (2),



A number of substantial changes are to be made to First Council Directive 73/239/EEC of 24 July 1973 on the coordination of laws, regulations and administrative provisions relating to the taking-up and pursuit of the business of direct insurance other than life assurance (3); Council Directive 78/473/EEC of 30 May 1978 on the coordination of laws, regulations and administrative provisions relating to Community co-insurance (4); Council Directive 87/344/EEC of 22 June 1987 on the coordination of laws, regulations and administrative provisions relating to legal expenses insurance (5); Second Council Directive 88/357/EEC of 22 June 1988 on the coordination of laws, regulations and administrative provisions relating to direct insurance other than life assurance and laying down provisions to facilitate the effective exercise of freedom to provide services (6); Council Directive 92/49/EEC of 18 June 1992 on the coordination of laws, regulations and administrative provisions relating to direct insurance other than life assurance (third non-life insurance Directive) (7); Directive 98/78/EC of the European Parliament and of the Council of 27 October 1998 on the supplementary supervision of insurance undertakings in an insurance group (8); Directive 2001/17/EC of the European Parliament and of the Council of19 March 2001 on the reorganisation and winding-up of insurance undertakings (9); Directive 2002/83/EC of the European Parliament and of the Council of 5 November 2002 concerning life assurance (10); and Directive 2005/68/EC of the European Parliament and of the Council of 16 November 2005 on reinsurance (11). In the interests of clarity those Directives should be recast.


In order to facilitate the taking-up and pursuit of the activities of insurance and reinsurance, it is necessary to eliminate the most serious differences between the laws of the Member States as regards the rules to which insurance and reinsurance undertakings are subject. A legal framework should therefore be provided for insurance and reinsurance undertakings to conduct insurance business throughout the internal market thus making it easier for insurance and reinsurance undertakings with head offices in the Community to cover risks and commitments situated therein.


It is in the interests of the proper functioning of the internal market that coordinated rules be established relating to the supervision of insurance groups and, with a view to the protection of creditors, to the reorganisation and winding-up proceedings in respect of insurance undertakings.


It is appropriate that certain undertakings which provide insurance services are not covered by the system established by this Directive due to their size, their legal status, their nature – as being closely linked to public insurance systems – or the specific services they offer. It is further desirable to exclude certain institutions in several Member States, the business of which covers only a very limited sector and is restricted by law to a specific territory or to specified persons.


Very small insurance undertakings fulfilling certain conditions, including gross premium income below EUR 5 million, are excluded from the scope of this Directive. However, all insurance and reinsurance undertakings which are already licensed under the current Directives should continue to be licensed when this Directive is implemented. Undertakings that are excluded from the scope of this Directive should be able to make use of the basic freedoms granted by the Treaty. Those undertakings have the option to seek authorisation under this Directive in order to benefit from the single licence provided for in this Directive.


It should be possible for Member States to require undertakings that pursue the business of insurance or reinsurance and which are excluded from the scope of this Directive to register. Member States may also subject those undertakings to prudential and legal supervision.


Council Directive 72/166/EEC of 24 April 1972 on the approximation of the laws of Member States relating to insurance against civil liability in respect of the use of motor vehicles, and to the enforcement of the obligation to insure against such liability (12); Seventh Council Directive 83/349/EEC of 13 June 1983 based on the Article 54(3)(g) of the Treaty on consolidated accounts (13); Second Council Directive 84/5/EEC of 30 December 1983 on the approximation of the laws of the Member States relating to insurance against civil liability in respect of the use of motor vehicles (14); Directive 2004/39/EC of the European Parliament and of the Council of 21 April 2004 on markets in financial instruments (15); and Directive 2006/48/EC of the European Parliament and of the Council of 14 June 2006 relating to the taking up and pursuit of the business of credit institutions (16) lay down general rules in the fields of accounting, motor insurance liability, financial instruments and credit institutions and provide for definitions in those areas. It is appropriate that certain of the definitions laid down in those directives apply for the purposes of this Directive.


The taking-up of insurance or of reinsurance activities should be subject to prior authorisation. It is therefore necessary to lay down the conditions and the procedure for the granting of that authorisation as well as for any refusal.


The directives repealed by this Directive do not lay down any rules in respect of the scope of reinsurance activities that an insurance undertaking may be authorised to pursue. It is for the Member States to decide to lay down any rules in that regard.


References in this Directive to insurance or reinsurance undertakings should include captive insurance and captive reinsurance undertakings, except where specific provision is made for those undertakings.


Since this Directive constitutes an essential instrument for the achievement of the internal market, insurance and reinsurance undertakings authorised in their home Member States should be allowed to pursue, throughout the Community, any or all of their activities by establishing branches or by providing services. It is therefore appropriate to bring about such harmonisation as is necessary and sufficient to achieve the mutual recognition of authorisations and supervisory systems, and thus a single authorisation which is valid throughout the Community and which allows the supervision of an undertaking to be carried out by the home Member State.


Directive 2000/26/EC of the European Parliament and of the Council of 16 May 2000 on the approximation of the laws of the Member States relating to insurance against civil liability in respect of the use of motor vehicles (Fourth motor insurance Directive) (17) lays down rules on the appointment of claims representatives. Those rules should apply for the purposes of this Directive.


Reinsurance undertakings should limit their objects to the business of reinsurance and related operations. Such a requirement should not prevent a reinsurance undertaking from pursuing activities such as the provision of statistical or actuarial advice, risk analysis or research for its clients. It may also include a holding company function and activities with respect to financial sector activities within the meaning of Article 2(8) of Directive 2002/87/EC of the European Parliament and of the Council of 16 December 2002 on the supplementary supervision of credit institutions, insurance undertakings and investment firms in a financial conglomerate (18). In any event, that requirement does not allow the pursuit of unrelated banking and financial activities.


The protection of policy holders presupposes that insurance and reinsurance undertakings are subject to effective solvency requirements that result in an efficient allocation of capital across the European Union. In light of market developments the current system is no longer adequate. It is therefore necessary to introduce a new regulatory framework.


In line with the latest developments in risk management, in the context of the International Association of Insurance Supervisors, the International Accounting Standards Board and the International Actuarial Association and with recent developments in other financial sectors an economic risk-based approach should be adopted which provides incentives for insurance and reinsurance undertakings to properly measure and manage their risks. Harmonisation should be increased by providing specific rules for the valuation of assets and liabilities, including technical provisions.


The main objective of insurance and reinsurance regulation and supervision is the adequate protection of policy holders and beneficiaries. The term beneficiary is intended to cover any natural or legal person who is entitled to a right under an insurance contract. Financial stability and fair and stable markets are other objectives of insurance and reinsurance regulation and supervision which should also be taken into account but should not undermine the main objective.


The solvency regime laid down in this Directive is expected to result in even better protection for policy holders. It will require Member States to provide supervisory authorities with the resources to fulfil their obligations as set out in this Directive. This encompasses all necessary capacities, including financial and human resources.


The supervisory authorities of the Member States should therefore have at their disposal all means necessary to ensure the orderly pursuit of business by insurance and reinsurance undertakings throughout the Community whether pursued under the right of establishment or the freedom to provide services. In order to ensure the effectiveness of the supervision all actions taken by the supervisory authorities should be proportionate to the nature, scale and complexity of the risks inherent in the business of an insurance or reinsurance undertaking, regardless of the importance of the undertaking concerned for the overall financial stability of the market.


This Directive should not be too burdensome for small and medium-sized insurance undertakings. One of the tools by which to achieve that objective is the proper application of the proportionality principle. That principle should apply both to the requirements imposed on the insurance and reinsurance undertakings and to the exercise of supervisory powers.


In particular, this Directive should not be too burdensome for insurance undertakings that specialise in providing specific types of insurance or services to specific customer segments, and it should recognise that specialising in this way can be a valuable tool for efficiently and effectively managing risk. In order to achieve that objective, as well as the proper application of the proportionality principle, provision should also be made specifically to allow undertakings to use their own data to calibrate the parameters in the underwriting risk modules of the standard formula of the Solvency Capital Requirement.


This Directive should also take account of the specific nature of captive insurance and captive reinsurance undertakings. As those undertakings only cover risks associated with the industrial or commercial group to which they belong, appropriate approaches should thus be provided in line with the principle of proportionality to reflect the nature, scale and complexity of their business.


The supervision of reinsurance activity should take account of the special characteristics of reinsurance business, notably its global nature and the fact that the policy holders are themselves insurance or reinsurance undertakings.


Supervisory authorities should be able to obtain from insurance and reinsurance undertakings the information which is necessary for the purposes of supervision, including, where appropriate, information publicly disclosed by an insurance or reinsurance undertaking under financial reporting, listing and other legal or regulatory requirements.


The supervisory authorities of the home Member State should be responsible for monitoring the financial health of insurance and reinsurance undertakings. To that end, they should carry out regular reviews and evaluations.


Supervisory authorities should be able to take account of the effects on risk and asset management of voluntary codes of conduct and transparency complied with by the relevant institutions dealing in unregulated or alternative investment instruments.


The starting point for the adequacy of the quantitative requirements in the insurance sector is the Solvency Capital Requirement. Supervisory authorities should therefore have the power to impose a capital add-on to the Solvency Capital Requirement only under exceptional circumstances, in the cases listed in this Directive, following the supervisory review process. The Solvency Capital Requirement standard formula is intended to reflect the risk profile of most insurance and reinsurance undertakings. However, there may be some cases where the standardised approach does not adequately reflect the very specific risk profile of an undertaking.


The imposition of a capital add-on is exceptional in the sense that it should be used only as a measure of last resort, when other supervisory measures are ineffective or inappropriate. Furthermore, the term exceptional should be understood in the context of the specific situation of each undertaking rather than in relation to the number of capital add-ons imposed in a specific market.


The capital add-on should be retained for as long as the circumstances under which it was imposed are not remedied. In the event of significant deficiencies in the full or partial internal model or significant governance failures the supervisory authorities should ensure that the undertaking concerned makes every effort to remedy the deficiencies that led to the imposition of the capital add-on. However, where the standardised approach does not adequately reflect the very specific risk profile of an undertaking the capital add-on may remain over consecutive years.


Some risks may only be properly addressed through governance requirements rather than through the quantitative requirements reflected in the Solvency Capital Requirement. An effective system of governance is therefore essential for the adequate management of the insurance undertaking and for the regulatory system.


The system of governance includes the risk-management function, the compliance function, the internal audit function and the actuarial function.


A function is an administrative capacity to undertake particular governance tasks. The identification of a particular function does not prevent the undertaking from freely deciding how to organise that function in practice save where otherwise specified in this Directive. This should not lead to unduly burdensome requirements because account should be taken of the nature, scale and complexity of the operations of the undertaking. It should therefore be possible for those functions to be staffed by own staff, to rely on advice from outside experts or to be outsourced to experts within the limits set by this Directive.


Furthermore, save as regards the internal audit function, in smaller and less complex undertakings it should be possible for more than one function to be carried out by a single person or organisational unit.


The functions included in the system of governance are considered to be key functions and consequently also important and critical functions.


All persons that perform key functions should be fit and proper. However, only the key function holders should be subject to notification requirements to the supervisory authority.


For the purpose of assessing the required level of competence, professional qualifications and experience of those who effectively run the undertaking or have other key functions should be taken into consideration as additional factors.


All insurance and reinsurance undertakings should have, as an integrated part of their business strategy, a regular practice of assessing their overall solvency needs with a view to their specific risk profile (own-risk and solvency assessment). That assessment neither requires the development of an internal model nor serves to calculate a capital requirement different from the Solvency Capital Requirement or the Minimum Capital Requirement. The results of each assessment should be reported to the supervisory authority as part of the information to be provided for supervisory purposes.


In order to ensure effective supervision of outsourced functions or activities, it is essential that the supervisory authorities of the outsourcing insurance or reinsurance undertaking have access to all relevant data held by the outsourcing service provider, regardless of whether the latter is a regulated or unregulated entity, as well as the right to conduct on-site inspections. In order to take account of market developments and to ensure that the conditions for outsourcing continue to be complied with, the supervisory authorities should be informed prior to the outsourcing of critical or important functions or activities. Those requirements should take into account the work of the Joint Forum and are consistent with the current rules and practices in the banking sector and Directive 2004/39/EC and its application to credit institutions.


In order to guarantee transparency, insurance and reinsurance undertakings should publicly disclose – that is to say make it available to the public either in printed or electronic form free of charge – at least annually, essential information on their solvency and financial condition. Undertakings should be allowed to disclose publicly additional information on a voluntary basis.


Provision should be made for exchanges of information between the supervisory authorities and authorities or bodies which, by virtue of their function, help to strengthen the stability of the financial system. It is therefore necessary to specify the conditions under which those exchanges of information should be possible. Moreover, where information may be disclosed only with the express agreement of the supervisory authorities, those authorities should be able, where appropriate, to make their agreement subject to compliance with strict conditions.


It is necessary to promote supervisory convergence not only in respect of supervisory tools but also in respect of supervisory practices. The Committee of European Insurance and Occupational Pensions Supervisors (CEIOPS) established by Commission Decision 2009/79/EC (19) should play an important role in this respect and report regularly to the European Parliament and the Commission on the progress made.


The objective of the information and report to be presented in relation to capital add-ons by CEIOPS is not to inhibit their use as permitted under this Directive but to contribute to an ever higher degree of supervisory convergence in the use of capital add-ons between supervisory authorities in the different Member States.


In order to limit the administrative burden and avoid duplication of tasks, supervisory authorities and national statistical authorities should cooperate and exchange information.


For the purposes of strengthening the supervision of insurance and reinsurance undertakings and the protection of policy holders, the statutory auditors within the meaning of Directive 2006/43/EC of the European Parliament and of the Council of 17 May 2006 on statutory audits of annual accounts and consolidated accounts (20) should have a duty to report promptly any facts which are likely to have a serious effect on the financial situation or the administrative organisation of an insurance or a reinsurance undertaking.

"M4A1" and "Colt M4" redirect here. For other uses, see M4 (disambiguation).

The M4 carbine is a shorter and lighter variant of the M16A2assault rifle. The M4 is a 5.56×45mm NATO, air-cooled, direct impingementgas-operated, magazine-fed carbine. It has a 14.5 in (370 mm) barrel and a telescoping stock.

The M4 carbine is extensively used by the United States Armed Forces and is largely replacing the M16 rifle in United States Army and United States Marine Corps combat units as the primary infantry weapon.[7][8]

The M4 is also capable of mounting the M203 and M320 grenade launchers. The distinctive step in its barrel is for mounting the M203 with the standard hardware. The M4 is capable of firing in semi-automatic and three-round burst modes (like the M16A2 and M16A4), while the M4A1 is capable of firing in semi-auto and fully automatic modes (like the M16A1 and M16A3).


Following the adoption of the M16 rifle, carbine variants were also adopted for close quarters operations. The CAR-15 family of weapons served through the Vietnam War. However, these carbines had design issues, as "the barrel length was halved" to 10 inches which "upset the ballistics", reducing its range and accuracy and leading "to considerable muzzle flash and blast, so that a large flash suppressor had to be fitted".[9] "Nevertheless, as a short-range weapon it is quite adequate and thus, [despite] its caliber, [the XM177 'Commando'] is classed as a submachine gun."[9] In 1984, Colt began work on a new carbine design called the XM4 combining the best features of the Colt Commando and later the M16A2 rifles.

In 1984, the first model was made, and it was tested in May 1985. The first models had an upper receiver with an A1 sight, and were given a shorter 11.5-inch barrel, but later ones were given a longer 14.5-inch barrel for the bayonet and the M203 Grenade Launcher. The second model was made in May 1986, and it was tested from May 1986 though May 1987; at the time it had an A2 Upper Sight, and it had the M16A2's 1:7 inch rifle twist, to use the heavier 62-grain M855 rounds. The extended barrel improved the XM4's ballistics, reduced muzzle blast and gave the XM4 the ability to mount a bayonet and the M203 grenade launcher. The XM4 was also given the cartridge deflector, as well as other minor refinements.[citation needed] In May 1991, the XM4 was renamed to the M4, and Colt made a manual.

The M4 was officially accepted into service by the U.S. military in 1994, and was first used operationally by U.S. troops deployed to Kosovo in 1999 in support of the NATO-led KFOR peacekeeping force. It would subsequently be used heavily by U.S. forces during the Global War on Terrorism, including Operation Enduring Freedom and Operation Iraqi Freedom. In the U.S. Army, the M4 largely replaced M16A2s as the primary weapon of forward deployed personnel by 2005.[10] The M4 carbine also replaced most submachine guns and selected handguns in U.S. military service,[10] as it fires more effective rifle ammunition that offers superior stopping power and is better able to penetrate modern body armor.[citation needed]

The United States Marine Corps has ordered its officers (up to the rank of Lieutenant Colonel) and staff non-commissioned officers to carry the M4 carbine instead of the M9 handgun.[11] This is in keeping with the Marine Corps doctrine, "Every Marine a rifleman". The Marine Corps, however, chose the full-sized M16A4 over the M4 as its standard infantry rifle. United States Navycorpsmen E5 and below are also issued M4s instead of the M9.[12] While ordinary riflemen in the Marine Corps were armed with M16A4s, M4s were fielded by troops in positions where a full-length rifle would be too bulky, including vehicle operators and fireteam and squad leaders. As of 2013, the U.S. Marine Corps had 80,000 M4 carbines in their inventory.[13][14]

By July 2015, major Marine Corps commands were endorsing switching to the M4 over the M16A4 as the standard infantry rifle, just as the Army had done. This is because of the carbine's lighter weight, compact length, and ability to address modern combat situations that happen mostly within close quarters; if a squad needs to engage at longer ranges, the M27 IAR can be used as a designated marksman rifle. Approval of the change would move the M16 to support personnel, while armories already had the 17,000 M4s in the inventory needed to outfit all infantrymen who needed one.[15] In October 2015, CommandantRobert Neller formally approved of making the M4 carbine the primary weapon for all infantry battalions, security forces, and supporting schools in the U.S. Marine Corps. The switch was to begin in early 2016 and be completed by September 2016.[16] In December 2017, the Marine Corps revealed a decision to equip every Marine in an infantry squad with the M27, replacing the M4 in that part of the service.[17]MARSOC will retain the M4, as its shorter barrel is more suited to how they operate in confined spaces.[18]

Improved M4[edit]

On 1 July 2009, the U.S. Army took complete ownership of the M4 design.[19] This allowed companies other than Colt to compete with their own M4 designs. The Army planned on fielding the last of its M4 requirement in 2010.[19] On 30 October 2009, Army weapons officials proposed a series of changes to the M4 to Congress. Requested changes included an electronic round counter that records the number of shots fired, a heavier barrel, and possibly replacing the direct impingement system with a gas piston system.

The benefits of this, however, have come under scrutiny from both the military and civilian firearms community.[20][21] According to a PDF detailing the M4 Carbine improvement plans released by PEO Soldier, the direct impingement system would be replaced only after reviews were done comparing the direct impingement system to commercial gas piston operating system to find out and use the best available operating system in the U.S. Army's improved M4A1.[22]

In September 2010, the Army announced it would buy 12,000 M4A1s from Colt Firearms by the end of 2010, and would order 25,000 more M4A1s by early 2011. The service branch planned to buy 12,000 M4A1 conversion kits in early 2011. In late 2011, the Army bought 65,000 more conversion kits. From there the Army had to decide if it would upgrade all of its M4s.[23]

On 21 April 2012, the U.S. Army announced to begin purchasing over 120,000 M4A1 carbines to start reequipping front line units from the original M4 to the new M4A1 version. The first 24,000 were to be made by Remington Arms Company. Remington was to produce the M4A1s from mid-2013 to mid-2014.[24] After completion of that contract, it was to be between Colt and Remington to produce over 100,000 more M4A1s for the U.S. Army. Because of efforts from Colt to sue the Army to force them not to use Remington to produce M4s, the Army reworked the original solicitation for new M4A1s to avoid legal issues from Colt.[25] On 16 November 2012, Colt's protest of Remington receiving the M4A1 production contract was dismissed.[26] Instead of the contract being re-awarded to Remington, the Army awarded the contract for 120,000 M4A1 carbines worth $77 million to FN Herstal on 22 February 2013.[27][28] The order is expected to be completed by 2018.[29]

Army upgrades[edit]

The M4 product improvement program (PIP) is the effort by the U.S. Army to modernize its inventory of M4 service rifles. Phase I consists of converting and replacing regular M4s with the M4A1 version. This variant of the rifle is fully automatic and has a heavier barrel, and is given ambidextrous fire controls. Phase II of the PIP explored developing a new bolt carrier. 11 designs were submitted. The competition was scheduled to conclude in summer 2013, but ended in April 2012. Over six months of testing revealed that the current bolt carrier assembly outperformed the competing designs, especially in the areas of reliability, durability, and high-temp and low-temp tests. Phase II also includes a competition for a free-floating forward rail assembly. The Army may award contracts to up to three finalists in early 2013, with the selection of a final winner in early 2014. If the Army determines that the winning rail system should be procured, delivery of new rail is anticipated by the summer of 2014.[30]

In March 2015, the Army launched a market survey to see what the small-arms industry could offer to further enhance the M4A1 to an "M4A1+" standard. Several upgrade options include an extended forward rail that will allow for a free-floated barrel for improved accuracy with a low-profile gas block that would do away with the traditional triangular fixed front sight, removable front and rear flip-up back-up iron sights, a coyote tan or "neutral color" rail for reduced visual detection, a more effective flash suppressor/muzzle brake, an improved charging handle, and a new single-stage trigger module.[31] In June 2016, the M4A1+ was canceled after reviewing the offerings and determining that there were no major upgrades currently offered.[32]


The M4 and its variants fire 5.56×45mm NATO (and .223 Remington) ammunition, and are gas-operated, magazine-fed, selective fire firearms with either a multi-position telescoping stock or a fixed A2 or LE tactical stock.[33]

The M4 is a shorter and lighter variant of the M16A2 rifle, with 80% parts commonality.[34] The M4 is similar to much earlier compact M16 versions, such as the 1960s-era XM177 family. Some of those visual similarities are obvious in both weapons.

As with many carbines, the M4 is handy and more convenient to carry than a full-length rifle. The price is slightly inferior ballistic performance compared to the full-size M16, with its 5.5" (14 cm) longer barrel. This becomes most apparent at ranges of 180 m (200 yards) and beyond.

While the M4's maneuverability makes it a candidate for non-infantry troops (vehicle crews, clerks and staff officers), it also makes it ideal for close quarters battle (CQB). The M4, along with the M16A4, have mostly replaced the M16A2 in the Army and Marines. The U.S. Air Force, for example, has transitioned completely to the M4 for Security Forces squadrons, while other armed personnel retain the M16A2. The US Navy uses M4A1s for Special Operations and vehicle crews.

Some features of the M4 and M4A1 compared to a full-length M16-series rifle include:

  • Compact size
  • Shortened barrel 14.5 in (370 mm), which includes the shorter carbine gas system.
  • Telescoping buttstock

However, there have been some criticisms of the carbine, such as lower muzzle velocities and louder report due to the shorter barrel, additional stress on parts because of the shorter gas system, and a tendency to overheat faster than the M16A2.


Like all the variants of the M16, the M4 and the M4A1 can be fitted with many accessories, such as night vision devices, suppressors, laser pointers, telescopic sights, bipods, either the M203 or M320 grenade launchers, the M26 MASS shotgun, forward hand grips, and anything else compatible with a MIL-STD-1913 Picatinny rail.

Other common accessories include the AN/PEQ-2 and AN/PEQ-15 multi-mode laser and light modules, Advanced Combat Optical Gunsight (ACOG), and M68 CCO. EOTech holographic weapon sights are part of the SOPMOD II package. Visible and IR (infrared) lights of various manufacturers are also commonly attached using various mounting methods. As with all versions of the M16, the M4 accepts a blank-firing attachment (BFA) for training purposes.

In January 2017, a USMC unit deployed with suppressors mounted to every infantry M4 service weapon. Exercises showed that having all weapons suppressed improved squad communication and surprise during engagements; disadvantages included additional heat and weight, increased maintenance, and the greater cost of equipping so many troops with the attachment.[35]


M4 feedramps are extended from the barrel extension into the upper receiver. This can help alleviate feeding problems which may occur as a result of the increased pressure of the shortened gas system of the M4. This problem is primarily seen in full-auto applications.

SOPMOD Block I[edit]

U.S. Special Operations Command (USSOCOM) developed the Special Operations Peculiar Modification (SOPMOD) Block I kit for the carbines used by units under its jurisdiction. The kit features an M4A1, a Rail Interface System (RIS) handguard developed by Knight's Armament Company, a shortened quick-detachable M203 grenade launcher and leaf sight, a KAC sound suppressor, a KAC back-up rear sight, an Insight Technologies AN/PEQ-2A visible laser/infrared designator, along with Trijicon's ACOG TA-01NSN model and Reflex sights, and a night vision sight. This kit was designed to be configurable (modular) for various missions, and the kit is currently in service with special operations units.

SOPMOD Block II[edit]

A second-generation SOPMOD kit (now known as SOPMOD II) includes innovative optics, such as the Elcan Specter DR, Trijicon's ACOG TA01 ECOS model, and the Eotech 553. Block II uses the RIS II rails manufactured by Daniel Defense in both a 9.5 and 12.5 length.


Further information on M4 carbine variants: List of Colt AR-15 & M16 rifle variants

Except for the very first delivery order, all U.S. military-issue M4 and M4A1 carbines possess a flat-top NATOM1913-specification (Picatinny) rail on top of the receiver for attachment of optical sights and other aiming devices — Trijicon TA01 and TA31 Advanced Combat Optical Gunsights (ACOG), EOTech 550 series holographic sights, and AimpointM68 Close Combat Optic (M68 CCO) being the favorite choices — and a detachable rail-mounted carrying handle. Standards are the Colt Model 920 (M4) and 921 (M4A1).

Variants of the carbine built by different manufacturers are also in service with many other foreign special forces units, such as the Australian Special Air Service Regiment (SASR). While the SASR uses weapons of essentially the same pattern built by Colt for export (Colt uses different models to separate weapons for the U.S. military and those for commercial/export purposes), the British SAS uses a variant on the basic theme, the Colt Canada (formerly Diemaco) C8SFW.

M4 MWS (Modular Weapon System)[edit]

Colt Model 925 carbines were tested and fitted with the Knight's Armament Corporation (KAC) M4 RAS under the designation M4E2, but this designation appears to have been scrapped in favor of mounting this system to existing carbines without changing the designation. The U.S. Army Field Manual specifies for the Army that adding the Rail Adapter System (RAS) turns the weapon into the M4 MWS or Modular Weapon System.


The M4A1 carbine is a fully automatic variant of the basic M4 carbine intended for special operations use. The M4A1 was introduced in May 1991, and was in service in 1994. The M4A1 has a "S-1-F" (safe/semi-automatic/fully automatic) trigger group, while the M4 has a "S-1-3" (safe/semi-automatic/3-round burst) trigger group. The M4A1 is used by almost all U.S special operation units including, but not limited to, Marine Force Recon, Army Rangers, Army Special Forces, Navy SEALs, United States Air Force Pararescue and Air Force Combat Control Teams. It has a maximum effective range of about 500 to 600 meters (550–660 yd).[6] The fully automatic trigger gives a more consistent trigger pull, which leads to better accuracy.[36] According to Mark A. Westrom, owner of ArmaLite, Inc., automatic fire is better for clearing rooms than burst fire.[37]

In the last few years, M4A1 carbines have been refitted or received straight from the factory with barrels with a thicker profile under the handguard. This is for a variety of reasons such as heat dissipation during full-auto, and accuracy as a byproduct of barrel weight. These heavier barrel weapons are also fitted with a heavier buffer known as the H2. Out of three sliding weights inside the buffer, the H2 possesses two tungsten weights and one steel weight, versus the standard H buffer, which uses one tungsten weight and two steel weights. These weapons, known by Colt as the Model 921HB (for Heavy Barrel), have also been designated M4A1, and as far as the government is concerned the M4A1 represents both the 921 and 921HB.

Conversion of M4s to the M4A1 began in 2014, the start of all U.S. Army forces being equipped with the automatic variant.[38] Though in service with special forces, combat in Afghanistan showed the need for providing automatic suppression fires during fire and movement for regular soldiers. The 101st Airborne Division began fielding new-built M4A1s in 2012, and the U.S. 1st Infantry Division became the first unit to convert their M4s to M4A1-standard in May 2014. Upgrades included a heavier barrel to better dissipate heat from sustained automatic firing, which also helps the rifles use the M855A1 EPR that has higher proof pressures and puts more strain on barrels. The full-auto trigger group has a more consistent trigger pull, whereas the burst group's pull varies on where the fire control group is set, resulting in more predictable and better accuracy on semi-automatic fire. Another addition is an ambidextrous selector lever for easier use with left-handed shooters. The M4-M4A1 conversion only increases weapon weight from 7.46 lb (3.38 kg) to 7.74 lb (3.51 kg), counting a back-up iron sight, forward pistol grip, empty magazine, and sling. Each carbine upgrade costs $240 per rifle, for a total cost of $120 million for half a million conversions. 300 conversions can be done per day to equip a brigade combat team per week, with all M4A1 conversions to be completed by 2019.[39][40]

Mark 18 CQBR[edit]

Main article: Close Quarters Battle Receiver

The Mk 18 Close Quarters Battle Receiver is an M4A1 with a 10.3-inch barrel upper receiver.[41] Current contractors for the Mark 18 are Colt and Lewis Machine & Tool (LMT) NSN 1005-01-527-2288.

Enhanced M4[edit]

For the Individual Carbine competition, Colt submitted their Enhanced M4 design, also known as the Colt Advanced Piston Carbine (APC). The weapon has a suppression-ready fluted barrel, which is lighter and cools better than previous M4 barrels. It is claimed to have "markedly better" accuracy. To improve reliability, Colt used an articulating link piston (ALP) which "reduces the inherent stress in the piston stroke by allowing for deflection and thermal expansion".[42] In traditional gas piston operating systems, the force of the piston striking the bolt carrier can push the bolt carrier downwards and into the wall of the buffer tube, leading to accelerated wear and even chipped metal. This is known as carrier tilt. The ALP allows the operating rod to wiggle to correct for the downward pressure on the bolt and transfers the force straight backwards in line with the bore and buffer assembly, eliminating the carrier tilt. This relieves stress on parts and helps to increase accuracy.[43] The Individual Carbine competition was canceled before a winning weapon was chosen.[36]

Colt Commando[edit]

Though Colt has focused its attention on carbines with 14.5-inch barrels and rifles with 20-inch barrels, Colt continues to make carbines with 11.5-inch barrels, which it calls Commandos. The Colt Model 733, is their first design, and it was made in 1987. It was referred to as the M16A2 Commando, and later the M4 Commando. Unlike the XM177, the Colt Commando was a shorter variant of the M16A2. Originally, Commandos were assembled from whatever spare parts are available, so Model 733 Commandos could have A1-style upper receivers with case deflectors or A2-style upper receivers, and M16A1-profile 1:7 or M16A2-profile 1:7 barrels. Depending on the specific models, Commandos may have had three-position fire control groups (safe/semi-automatic/three-round burst), or four-position having both full-automatic and burst. The modern Model 933 has a "flattop" receiver, with a removable carrying handle and a MIL-STD-1913 Picatinny rail, with semi-automatic and automatic fire. The Model 935 Commando has the features of the Model 933, but has three-round burst fire instead of automatic. Though originally called the M16A2 Commando, Colt markets them as the M4 Commando around 1995.

Armwest LLC M4[edit]

In 2014, American firearms designer Jim Sullivan provided a video interview regarding his contributions to the M16/M4 family of rifles when working for Armalite. A noted critic of the M4, he illustrates the deficiencies found in the rifle in its current configuration. In the video, he demonstrates his "Arm West LLC modified M4", with enhancements he believes necessary to rectify the issues with the weapon. Proprietary issues aside, the weapon is said to borrow features in his prior development, the Ultimax. Sullivan has stated (without exact details as to how) the weapon can fire from the closed bolt in semi-automatic and switch to open bolt when firing in fully automatic, improving accuracy. The weight of the cyclic components of the gun has been doubled (while retaining the weapon's weight at less than 8 pounds). Compared to the standard M4, which in automatic fires 750-950 rounds a minute, the rate of fire of the Arm West M4 is heavily reduced both to save ammunition and reduce barrel wear. The reduced rate also renders the weapon more controllable and accurate in automatic firing.[44]


The M4 carbine has been used for close quarters operations where the M16 would be too long and bulky to use effectively. It has been a compact, light, customizable, and accurate weapon. This has come at the cost of reliability and maintainability. Failure to maintain the M4 causes malfunctions. This became apparent as it saw continued use in the sandy environments of Iraq and Afghanistan.[45] Despite this, in post-combat surveys, 94 percent of soldiers rated the M4 as an effective weapons system.[46]

Early feedback[edit]

By late 2002, 89 percent of U.S. troops reported they were confident with the M4, but they had a range of problems. 34 percent of users said the handguards rattled and became excessively hot when firing, and 15 percent had trouble zeroing the M68 Close Combat Optic. 35 percent added barber brushes and 24 percent added dental picks to their cleaning kits. There were many malfunctions, including 20 percent of users experiencing a double feed, 15 percent experiencing feeding jams, and 13 percent saying that feeding problems were due to magazines. 20 percent of users were dissatisfied with weapon maintenance. Some had trouble locking the magazine into the weapon and having to chamber a round in order to lock the magazine. Soldiers also asked for a larger round to be able to kill targets with one shot. New optics and handguards made usage of the M4 easier, and good weapon maintenance reduced the number of misfeeds.[47]

2006 CNA report[edit]

In December 2006, the Center for Naval Analyses released a report on U.S. small arms in combat. The CNA conducted surveys on 2,608 troops returning from combat in Iraq and Afghanistan over the past 12 months. Only troops who fired their weapons at enemy targets were allowed to participate. 917 troops were armed with M4 Carbines, making up 35 percent of the survey. 89 percent of M4 users (816 troops) reported they were satisfied with the weapon. 90 percent (825 troops) were satisfied with handling qualities such as handguards, size, and weight. M4 users had the highest levels of satisfaction with weapon performance, including 94 percent (862 troops) with accuracy, 92 percent (844 troops) with range, and 93 percent (853 troops) with rate of fire. Only 19 percent of M4 users (174 troops) reported a stoppage, while 82 percent of those that experienced a stoppage said it had little impact on their ability to clear the stoppage and re-engage their target. 53 percent of the M4 users (486 troops) never experienced failures of their magazines to feed. 81 percent (743 troops) did not need their rifles repaired while in theater. 80 percent (734 troops) were confident in the M4's reliability, defined as level of soldier confidence their weapon will fire without malfunction, and 83 percent (761 troops) were confident in its durability, defined as level of soldier confidence their weapon will not break or need repair. Both factors were attributed to high levels of soldiers performing their own maintenance. 54 percent of M4 users offered recommendations for improvements. 20 percent of requests were for greater bullet lethality, and 10 percent was better quality magazines, as well as other minor recommendations. Some M16 users expressed their desire to be issued the M4.[48] Some issues have been addressed with the issuing of the improved STANAG magazine in March 2009,[49][50] and the M855A1 Enhanced Performance Round in June 2010.[51]

2007 dust test[edit]

In the fall 2007, the Army tested the M4 against three other carbines in "sandstorm conditions" at Aberdeen Proving Ground, Maryland: the Heckler & KochXM8, Fabrique Nationale de HerstalSOF Combat Assault Rifle (SCAR) and the Heckler & Koch HK416. Ten of each type of rifle were used to fire 6,000 rounds each, for a total of 60,000 rounds per rifle type.[52] The M4 suffered far more stoppages than its competitors: 882 stoppages, 19 requiring an armorer to fix. The XM8 had the fewest stoppages, 116 minor stoppages and 11 major ones, followed by the FN SCAR with 226 stoppages and the HK416 with 233.[53][54]

Despite 863 minor stoppages—termed "class one" stoppages which require 10 seconds or less to clear, or "class two" stoppages which require more than ten seconds to clear—the M4 functioned well, with over 98 percent of the 60,000 total rounds firing without a problem. The Army said it planned to improve the M4 with a new cold-hammer-forged barrel to give longer life and more reliable magazines to reduce the stoppages. Magazine failures caused 239 of the M4's 882 failures. Army officials said the new magazines could be combat-ready by spring if testing went well.[55] The Army began issuing an improved STANAG magazine in March 2009.[49][50]

According to the Army, the M4 only suffered 296 stoppages, and said that the high number reported could be attributed to discrepancies in the scoring process. The Army testing command stated that if the number of stoppages caused by a broken part met some threshold, they would be eliminated from the final report pending redesign of the part. Colt also claimed that the testing conditions were unfair to the M4, as the M4s used in the test were normal guns from active inventory, with remaining service life varying randomly. Further, the trial M4s had burst-mode fire groups, which are more complicated and prone to failure than the fully automatic fire groups the other manufacturers presented for testing.[56]

There were three extreme dust tests performed in 2007. The 2nd Summer 2007 results showed a large difference from the later fall test with the M4 having 148 class 1 stoppages due to rifle malfunctions and 148 class 1 stoppages due to magazine stoppages. The full-size M16 rifle had a total of 61 stoppages during the same extreme dust test.[57]


In early 2010, two journalists from the New York Times spent three months with soldiers and Marines in Afghanistan. While there, they questioned around 100 infantrymen about the reliability of their M4 Carbines, as well as the M16 rifle. Troops did not report to be suffering reliability problems with their rifles. While only 100 troops were asked, they fought at least a dozen intense engagements in Helmand Province, where the ground is covered in fine powdered sand (called "moon dust" by troops) that can stick to firearms. Weapons were often dusty, wet, and covered in mud. Intense firefights lasted hours with several magazines being expended. Only one soldier reported a jam when his M16 was covered in mud after climbing out of a canal. The weapon was cleared and resumed firing with the next chambered round. Furthermore, a Marine Chief Warrant Officer reported that with his battalion's 700 M4s and 350 M16s, there were no issues.[58]

The reliability of the M4 has increased as the design was upgraded. In 1990, the M4 was required to fire 600 mean rounds between stoppages using M855 ammunition. In 2013, the current M4A1 version can fire 1,691 mean rounds between stoppages using M855A1 ammunition.[59]

During the 2009 Marine Corps Infantry Automatic Rifle testing the Colt IAR displayed a MRBS of CLASS I/II Stoppages of 952 rounds, with a MRBEFF of Class III Stoppages of 60,000 rounds.[60]

Gas piston[edit]

An array of firearms accessory makers have offered gas piston conversion kits for the M4. The claimed benefits include less needed lubrication for the bolt carrier group to run reliably and reduced fouling.[61] The argument against it is increased weight and reduced accuracy.[citation needed] The Enhanced M4 uses an articulating link piston operating system.

Complicating the Army search for higher reliability in the M4 is a number of observations of M4 gas piston alternatives that suffer unintended design problems. The first is that many of the gas piston modifications for the M4 isolate the piston so that piston jams or related malfunction require the entire weapon be disassembled, such disassembly cannot be performed by the end user and requires a qualified armorer to perform out of field, whereas almost any malfunction with the direct-impingement system can be fixed by the end user in field. The second is that gas piston alternatives use an off-axis operation of the piston that can introduce carrier tilt, whereby the bolt carrier fails to enter the buffer tube at a straight angle, resulting in part wearing. This can also tilt the bolt during extraction, leading to increased bolt lug failures. The third is that the use of a sound suppressor results in hot gases entering the chamber, regardless of a direct-gas impingement or gas piston design choice. The gas piston system may also cause the firearm to become proprietary to the manufacturer, making modifications and changes with parts from other manufacturers difficult.[21][62]


  • Colt's Manufacturing Company
  • Lewis Machine and Tool Company in Milan, Illinois, US
  • Bushmaster Firearms International, US
  • U.S. Ordnance, US
  • Remington Arms Company, US
  • THOR Global Defense Group, US
  • Daniel Defense in Black Creek, Georgia, US
  • Forjas Taurus São Leopoldo, RS, Brazil
  • FN Herstal, Belgium.
  • Bravo Company Manufacturing, in Hartland, Wisconsin, US
  • Black Label Armory, US
  • SME Ordnance, Malaysia[63]
  • Sarsılmaz, Turkey[64]

Trademark issues[edit]

The M4 was developed and produced for the United States government by Colt Firearms, which had an exclusive contract to produce the M4 family of weapons through 2011.[65] However, a number of other manufacturers offer M4-like firearms. Colt previously held a U.S. trademark on the term "M4".[66] Many manufacturers have production firearms that are essentially identical to a military M4, but with a 16" barrel. The Bushmaster M4 Type Carbine is a popular example. Civilian models are sometimes colloquially referred to as "M4gery" (em-FOR-jə-ree, a portmanteau of "M4" and "forgery"). Colt had maintained that it retains sole rights to the M4 name and design. Other manufacturers had long maintained that Colt had been overstating its rights, and that "M4" had now become a generic term for a shortened AR-15. In April 2004, Colt filed a lawsuit against Heckler & Koch and Bushmaster Firearms, claiming acts of trademark infringement, trade dress infringement, trademark dilution, false designation of origin, false advertising, patent infringement, unfair competition, and deceptive trade practices. Heckler & Koch later settled out of court, changing one product's name from "HK M4" to "HK416". However, on December 8, 2005, a District court judge in Maine granted a summary judgment in favor of Bushmaster Firearms, dismissing all of Colt's claims except for false advertising. On the latter claim, Colt could not recover monetary damages. The court also ruled that "M4" was now a generic name, and that Colt's trademark should be revoked.[67]


  •  Afghanistan: Used only by Afghan Army commandos.[68][69] M4s sold as part of a 2006 Foreign Military Sales package.[70] Additional M4s sold as a 2008 Foreign Military Sales package.[71]
  •  Albania: Used by Albanian Land Force 2015.[72]
  •  Antigua and Barbuda: M4/M4A1s announced to be sold via FMS program in 2017.[73]
  •  Argentina: Used by Argentine Army, Argentine Navy and Argentine National Gendarmerie[73]
  •  Australia: Used by the Special Operations Command, Clearance Divers.[74]
  •  Bolivia[citation needed]
  •  Bosnia & Herzegovina: M4A1s used by the military and air guard units.[71]
  •  Bangladesh: Used by Bangladesh Army Paracommandos, Dhaka Metropolitan Police SWAT teams and Special Warfare Diving And Salvage.[75][76]
  •  Bahrain: M4A1s sold as a 2008 Foreign Military Sales package.[71] More M4/M4A1s announced to be sold via FMS program in 2017.[73]
  •  Belize: M4s/M4A1s sold as part of a 2006 Foreign Military Sales package.[70] More M4/M4A1s announced to be sold via FMS program in 2017.[73]
  •  Brazil: Used by Military Police of Espirito Santo State, Military Police of Rio de Janeiro State,[77] the Brazilian Federal Police and Special Forces of the Brazilian Army and Brazilian Navy.[78]
  •  Canada: Used by various police units.[79] License made copies continue to be developed by Colt Canada, a successor to DIEMACO, and are known collectively as the C8 carbine.
  •  Croatia: User since 2003, several hundred purchased for Croatian ISF contingent as well as special forces in Croatia.[80]
  •  Czech Republic: Bushmaster M4A3 B.M.A.S. is used by (601st Special forces group, Military police, 43rd Airborne mechanized battalion) of Czech Army.[81]
  •  Colombia: M4A1s as part of a 2008 Foreign Military Sales.[71] More M4/M4A1s announced to be sold via FMS program in 2017.[73]
  •  Ecuador: M4s sold as a 2008 Foreign Military Sales package.[71]
  •  Egypt[82]
  •  El Salvador: M4s sold as part of a 2007 Foreign Military Sales package.[83] Additional M4s sold as a 2008 Foreign Military Sales package.[71]
  •  Georgia: Bushmaster AR-15 and M4 for police and military. A concept analogue, the G13 carbine was developed by the Scientific Technical Center Delta in 2012.[84][85][86] More M4/M4A1s announced to be sold via FMS program in 2017.[73]
  •  Ghana[87][88][89]
  •  Greece: Used by EKAM, All SF Army, Navy, Airforce units.[90]
The M4 with the newer, redesigned telescoping stock
An M4A1 just after firing, with an ejected case in mid-air; the M203 and M68 CCO are attached.
SOPMOD (Special Operations Peculiar Modification) Block I
M4A1 SOPMOD Block II in Afghanistan 2012
M4 MWS (Modular Weapon System) shown with various accessories including M203 grenade launcher, RIS foregrip, removable carry handle/rear sight assembly, AN/PEQ-4 laser system, M68 CCO reflex sight, and the AN/PVS-4 night vision optics
An M4A1 with a Close Quarter Battle Receiver. The barrel length is 10.3 inches.

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