What is the difference between the m4a1 and the m16a4

WIth four variations in service with the United States Military yes, there are still rear-echelon units with the M16A1 , the rifle has developed over time to suit the constantly advancing and adapting needs of our warfighters overseas. The most recent adaptation, the M16A4, was finalized in , giving our soldiers the ability to mount optics and accessories to the top rail and handguard, giving them a rifle more adaptable to their environment and fight.

Initially offered primarily to Special Operations troops, the M4 and M4A1 filled the role for a more compact weapon platform for urban environments, and for vehicle crewmembers with less space for a full size rifle. The Marines were the last holdout, but eventually moved towards adopting the M4 as well force wide. You can see the difference in dimensions. Many people will tell you that an AR15 is semi-auto only, and the M16 is full-auto. The original AR15 before it picked up a military name was fully-automatic, as well as plenty since then.

The most noticeable difference is that the civilian AR15 lower receiver does not have the third trigger pin hole for the auto sear above the safety selector. The trigger pocket is also typically milled to different dimensions to prevent the acceptance of an auto-sear as well.

However, this is not a rule. Many companies still sell their lowers with M16 trigger pocket dimensions, they are just missing the proverbial "third-hole". Drilling that third hole is what legally changes your AR from a semi-automatic rifle, into an illegal machine gun.

At present, other modifications to the M4 design are still in progress, responding to both current needs and anticipated future needs of the U. The 5. Its size gave it higher velocity with minimal recoil and created a flatter trajectory that improved accuracy.

The M4 uses the same cartridge, modified for greater impact at higher speeds. The modification is in response to current tactical situations where close combat is more common than in previous engagements, with most of combat occurring in battlegrounds with shorter sightlines e. There was also greater need for suppressive power, basically the capacity to shoot faster with more accuracy, which the M4's design has tried to meet.

The M16 has a standard barrel length of 39 inches 1 meter. At that length, it provides greater accuracy than the M14 or AK; however, the barrel is too long for close combat efficiency. Cut-down M16 barrels lose accuracy and create more flash, so a shorter carbine variant was needed to address current battlefield realities. The maximum range of an M16 is about 3, yards 2, meters , with an effective range of up to yards meters. Horizontal range is yards m and the lethal range is yards m.

The M4 barrel measures 33 inches mm with the stock extended and just The smaller barrel length allows for greater control in close quarters, not only for mobility, but also for firing. The barrel is easily interchangeable, a general design feature of the M4 aimed at making the weapon more versatile and easier to maintain in the field. The effective range of an M4 carbine is about yards m. The M16 is a rotating bolt rifle with a gas-operated direct impingement firing action.

The M4 is similar, but it does not use impingement for its firing action. In this, it hews more closely to the AK design in order to provide a more reliable firing action in field conditions. The M16 magazine is lightweight compared to that of other assault rifles.

It is manufactured from stamped or mold-pressed aluminum and is weaker structurally than most other weapons' magazines, leading to more frequent failure. M16s hold 20 or 30 bullets each and can be replaced quickly, though anyone who will use the rifle will need training for some time to master the replacement process.

The M4 magazine is sturdier to reduce in-field failure rates when dealing with sub-optimal conditions and possibly frequent impacts with the ground or structures as soldiers advance or take cover.

It holds 30 bullets and is somewhat easier to switch out than the M16's, but it does require some basic training for mastery. The basic M16 weighs between 7 and 9 pounds 3. The basic weight for the M4 is between 6 and 7 pounds 2. Most of the weight lost in the M4 is related to the barrel and stock, not to the metal-based parts that make up the firing mechanisms. One advantage the M16 has is that the selector switch is easily reached and set without needing to take eyes off of a target.

This lets the user switch from semi-automatic to automatic fire and back, but the switch's small size makes it difficult to use under stressful conditions. Left-handed users of the M16 complain that the design makes it difficult for them to field-strip it for maintenance. The selector switch is larger and easier to set without losing sight of targets, while the breakdown components for maintenance are relatively neutral, although still somewhat more favorable to right-handed users.

The M16, like all weapon systems, started out with a reputation of being less reliable than its predecessor the M Over time, most reliability issues were reduced to low-percentage events; however, the AK has long been regarded as more reliable in field conditions wet, sandy, dirty, etc.

One improvement the M16 provided was a much higher manufacturing standard that now gives the weapon a service life of 20, to 50, rounds or more, compared to other assault rifles that max out at between 8, and 25, rounds. A major factor in M16 maintenance is lubrication, for without consistent cleaning and oiling, the weapon's performance deteriorates noticeably, even in recent variants. On the upside, this is easy to manage in field conditions.

Although the M4 has not had as much extensive field use when compared to the M16 or the AK, it, too, showed some early reliability issues. The gas-piston system failed in several early variants, though the problem was traced to differences in manufacturing rather than intrinsic design flaws. With new iterations, the M4 quickly gained a reputation for reliability, both on the range and in field situations. Range tests now have the M4 firing at least 1, rounds before jamming, up from , while in field conditions, soldiers report almost no failures, with the ones that are reported often due to improper or overly-delayed maintenance.

The Army-issued M4 has undergone over 90 design improvements over the years, which led to the upgraded M4A1 model of the carbine.

The weapon still has its critics, however. As recently as , Army generals and soldiers have complained about jamming and overheating in all M4 models. Robert Scales , a military analyst and retired Army major general, has cited the M4's gas impingement system as its primary drawback and has argued that the gun cannot be improved without replacing the gas impingement system altogether.

In response to complaints, the Army has called for weapons manufacturers to begin producing another round of upgrades to the military-grade carbine. There are no plans to scrap the gas impingement system.

In , the government price of every new U.