Is a Longer Rifle Barrel more Accurate?

A large deciding factor in my latest rifle build has been barrel length. If I purchase a longer barrel that is more cumbersome, will my rifle be more accurate?

This is a question asked by many, which falls under the infamous trap of firearm related myths. So does a longer barrel really make a rifle more accurate?

The simple answer is no, a longer barrel does not determine a rifle’s accuracy. It may however make accuracy easier to achieve, particularly in the hands of a less-experienced shooter.

So what exactly does this mean? Well, a longer barrel has the ability to assist the shooter in achieving accuracy more naturally, by reducing felt recoil, jump angle and muzzle blast, and ultimately increasing the rifle’s effective range. The shorter barrel however has its advantages too, by increasing barrel rigidity and therefore promoting precision, reducing weight, increasing manoeuvrability, and aiding in concealment ability.

While accuracy is defined as the rifle’s ability to hit its aiming marker, precision is defined as the rifle’s ability to group well.

The Advantages of a Longer Rifle Barrel:

Reduction in felt recoil – thanks to the added weight, the longer barrel will produce less felt recoil, which will aid in promoting accurate follow-up shots, and in the case of a less-experienced shooter, prevent certain errors in trigger control, such as flinching. For those who aren’t aware, flinching is an error made by an inexperienced shooter whereby he tenses his muscles to counter the rifle’s felt recoil, and in doing so moves the position of the rifle just before the shot is released, therefore affecting the accuracy of the shot.

Reduced Jump Angle – a longer barrel reduces the rifle’s jump angle, as there is more weight toward the rifle’s forend. This may help the rifle stick closer to its zero when changing between firing positions. The upward movement of a rifle’s barrel caused by recoil is known as jump, and the bullet exists the barrel during a particular point of this angle of jump, known as the rifle’s jump angle. An experienced shooter will be well aware of his jump angle when changing from one supported position to the next, and he will account for the point of impact shift accordingly.

Reduction in Muzzle Blast – the longer barrel allows for more complete gun powder combustion to occur before the bullet exits the barrel, reducing the visible muzzle flash and audible blast as the hot propellant gases meet the cooler outside air. To a newbie, this can make firing the rifle a more pleasant experience, as there is less of a violent bang coming from the muzzle end of the rifle.

Increased Effective Range – having a longer barrel increases muzzle velocity, as the bullet has more time to accelerate within the barrel while being driven by the propellant’s burning gases, which in turn, increases the effective range of the rifle, allowing the bullet to travel further.

The Advantages of a Shorter Rifle Barrel:

Increased Barrel Rigidity – shorter barrels are more rigid, which should reduce barrel whip and harmonic vibrations, ultimately promoting consistency and precision. Barrel harmonics, or vibrations, are linked to finding a barrel’s sweet spot when matched with the perfect cartridge, and when these vibrations are altered, precision can be lost. Rigidity in a barrel helps keep these vibrations consistent once the sweet spot is found between a barrel and cartridge.

Ease of Manoeuvrability – the shorter overall length and reduced weight makes the weapon easier to manoeuvre in tight spaces, such as inside buildings, in dense overgrowth, and in vehicles or aircraft. It also increases handiness by allowing the shooter to bring the rifle up onto aim faster, marginally increasing target acquisition and engagement speed.

Reduced Weight – the reduction in overall weight allows for less fatigue when carrying the rifle over long distances and arduous terrain. This includes stalking, which can be a challenge in itself, and is common amongst hunters and snipers.

Increased Conceal-ability – a shorter barrel reduces the overall length of the firearm, making it easier to conceal, whether transporting the rifle from A to B, or trying to remain hidden in a well-established hide. A hide is a camouflaged shelter used to observe wildlife or nearby enemy within close proximity.

How Much Difference will an Extra 2 to 4 Inches Make?

While we’ve highlighted some good points above, the variation of effects from one barrel length to the next is often minor, as long as the barrels are similar in specifications, quality and thickness, and your decision lies between only a few inches in difference.

The following chart will give you an approximate variation between the three Armalite rifles shown above. A 168gr Match projectile is used for calculation purposes.

	Armalite 16″	Armalite 18″	Armalite 20″
Felt Recoil	14.25ft-lb	13.6ft-lb	12.4ft-lb
Muzzle Velocity	2483fps	2524fps	2566fps
Effective Range	895 meters	915 meters	940 meters
Total Weight	3.8kg or 8.4lbs	4.0kg or 8.8lbs	4.4kg or 9.7lbs
Overall Length	90cm or 35.5″	95cm or 37.5″	107cm or 42.3″

Note: the above figures are approximate. Effective range is measured at standard sea level pressure. Total weight is without optics, ammunition or accessories.

So what do the above results show us?

In terms of recoil, the 18-inch barrel will experience approximately 10 percent more felt recoil than the 20-inch version, while the 16-inch will experience around 15 percent more than the 20-inch barrel.

The muzzle velocities vary, increasing as barrel length grows, typically extending the rifle’s effective range by around 20 meters for every 2-inches of barrel

The weight and length reduction is fairly significant between the 20-inch and 16-inch version, allowing for easier manoeuvrability and handiness with the 16-inch option.

Tip: while a 16-inch barrel may experience around 15% more felt recoil than a 20-inch barrel, a suppressor can be fitted to negate this negative effect.

What are Common Barrel Lengths?

When it comes to semi-automatic rifles that are intended for use over medium to long distances, it is common to find barrel lengths ranging between 14.5 and 20-inches.

Bolt-action rifles typically have longer barrels than their semi-automatic counterparts, commonly ranging between 16 and 26-inches, with some measuring up to a whopping 30-inches.

Summary

So there you have it. The decision is yours to make, and you can rest assured that whichever barrel length you choose, you’ll most likely bring out your rifle’s true potential one way or another.

And don’t forget, if you plan on using a suppressor, you can expect the attachment to add a fair amount of length to your rifle, so a shorter barrel may not be such a bad idea. The suppressor will help reduce recoil and muzzle blast anyway.

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