Max Length of Continuous Fire for Ar15 Barrel

Two Kinds of Ranges

When discussing the range of a firearm's projectiles, it is critical to distinguish two similar but very distinct concepts:effective rangeandmaximum range.

Effective range

Most discussions of a firearm's range are abouteffective range. You may have heard of this term before, but what exactly does this mean? To put it simply, the effective range of a firearm is themaximum distance at which a shooter can expect tohit a target accurately.

Because many things can be called targets, military documentation goes further and defines two types of effective range:point target effective range andarea target effective range.

• Point target effective range:The maximum distance at which anaverage shooter can hit ahuman-sized target at least 50% of the time. In the vast majority of cases, this definition is the one assumed in discussions about effective range.
• Area target effective range:The maximum distance at which anaverage shooter can hit avehicle-sized target (such as a car) at least 50% of the time. Area target effectiveness is typically not relevant, as it is not a good representation of the firearm's mechanical accuracy.

Excluding shooter skill and aiming capabilities, multiple factors may significantly affect a firearm's effective range, including but not limited to:

• Quality of the ammunition used
• Projectile type employed by the ammunition
• Thebarrel's properties (length, twist rate, build quality)
• Shooter skill (marksmanship, aiming capabilities)
• Environmentand shooting conditions

Therefore, it is critical to understand that when you see effective range numbers, they areballpark estimates. Real-world resultsmay vary considerably.

If you want to test the effective range of AR-15 rifle, you can compare it to AR-10 which is closely related firearm on this detailed comparison guide.

Maximum range

Less discussed but no less important, a firearm's absolutemaximum range is the maximum distance at which projectiles fired out of the barrel remainlethal.

According to the NATO definition, a projectile stops being lethal when it's kinetic energyfalls below 85 Joule (approximately62.7 ft-lbf).

For comparison, a typical 62-grain bullet fired out of an AR-15 carbine typically exits the barrel atabout 2,800 ft/s, resulting in a kinetic energy of roughly1,085 ft-lbf. For this bullet to fall under the minimum lethal kinetic energy value, the bullet velocity needs to drop under 675 ft/s, requiring it to travel at least 1,400-1,500 yards.

However, due to bullet drop, this situation iswildly unrealistic, unless the shooter were to aim so high, the muzzle ends uppointed at the sky. Doing so would cause the bullet to take ona parabolic trajectory.

In other words, under normal conditions, it's almost always a certainty thatthe bullet will hit something before it drops under lethal velocity.

Therefore,minding your bullets' direction and trajectory isn't just sensible; it's part of thebasic rules of gun safety. As the saying goes: "Know your target and what is beyond."

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How Far Can I Shoot My AR-15?

It depends. The U.S. military, and in particular, the U.S. Army and the Marine Corps, arethe largest users of AR-15 type firearms and the organizations that tested and evaluated the rifle platform's capabilitiesthe most extensively.

Military-issued M16 rifles possess a20" barrel, whereas M4 carbines have a14.5" barrel. In contrast, a typicalAR-15 carbine has a16" barrel.

According to the US Army'sM16 and M4 operator's manual (TM-9-1005-319-10), the M16 rifle and M4 carbine possess the following traits:

• Maximum range (both platforms):Approximately 3,600 meters (3937 yards, or over 2.2 miles)
• Point target effective range:550 meters (602 yards) for the M16 rifle, 500 meters (547 yards) for the M4 carbine.
• Area target effective range: 800 meters (875 yards) for the M16 rifle, 600 meters (650 yards) for the M4 carbine.

Assuming mil-spec components and ammunition identical to that used by the military (62-grain ball ammo), the point targeteffective range of an AR-15 carbine chambered in 5.56mm should beapproximately the sameas that of a military M4 carbine.

With the effective range of AR-15 held constant but still the end goal would be the your accuracy firing this rifle.

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​The AR-15 Aftermarket

Unlike the military, civilians frequently customize their rifles and carbines with a wide array of parts, barrels, ammunition, and other accessories, some of which candramatically change the AR's overall performance.

The three most common ways of altering theeffective range of an AR-15 require changing theammunition, thebarrel length, or thechambering.

Ammunition

Switching to more accurate hunting or match-grade ammunition mayproduce tighter groups andextend the rifle's effective range with no other alterations.

For example, when shooting Mk262 mod 1, a type of 77-grain match-grade 5.56mm ammunition, Special Forces operators reported they could hit targets accurately and consistentlyat 800 yards or more using 18"-barreled rifles.

Barrel length

You may have noticed in the table above that the point target effective range of the M16 (20" barrel) ishigher than the M4's (14.5" barrel).

Switching to a longer barrel increases muzzle velocity and effective range, but onlyto a degree. While AR-15s with a barrel length of over 20" do exist, they are relatively rare; the longest examples typically do not exceed 24".

Adding more barrel length is a game of diminishing returns; past a certain point, the velocity and range gainedbecome negligible, resulting inadditional weight for no tangible benefit.

Rechambering

One of the most drastic ways of modifying your AR-15's performance is to rechamber it: changing parts so that it shoots a different caliber.

Switching to another caliber causes your AR-15 togain that caliber's ballistics and performance.

For example, an AR-15 chambered in6.5 Grendel will shoot.264-caliber projectilestypically ranging between 90 and 130 grains in weight, possessing an effective range of800 to 1,000 yards, depending on barrel length and bullet weight.

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Parting Shots

Even with extensive testing and evaluations, measuring the effective range of an AR-15 (or any other firearm) isa game of averages and estimates, not an exact science.

Remember thatthe most significant influence on a particular firearm's accuracy (and overall performance)is the shooter itself. Unskilled shooters may shootfar below the expected average effective range, whereasvery skilled ones may shoot far beyond it.

Ultimately, you can expect a standard 5.56mm AR-15 carbine fed with average 62-grain ammunition to be reasonably accurateat up to 500 yards. But remember that you needpractice and training to hit targets reliably and accurately at this distance.

While on the matter of AR-15, would prefer to use it for home defense or not? Check out on this article for more detailed discussion:AR-15 or AK-47 for Home Defense.

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Source: https://www.minutemanreview.com/ar-15-effective-range/