muzzle velocity, a bullet leaving a semi automatic

What Is Muzzle Velocity? – A Simple Explanation

When learning to shoot there is a lot of information to process. The practical application of handing a firearm for safety needs to acquired.

During the learning process, you may hear many terms whereby it’s assumed you know what the term means, but sometimes you need clarification you understand terms correctly. So, what is muzzle velocity?

Muzzle velocity is the speed of a projectile the moment it leaves the barrel. It’s measured in fps (feet per second / ft/s) and is always the determining factor in the power of a gun. Many factors affect the muzzle velocity such as cartridge power, bullet grain, and barrel length.

Shooting whether as a sport or hunting requires a lot of different factors when trying to place a round on target, but the muzzle velocity is the start of the ballistics for every bullet.

muzzle velocity, a bullet leaving a luger

 

What Is Muzzle Velocity

The precise definition, we can leave to the dictionary which simple states;

The speed of a projectile, usually expressed in feet or meters per second, as it leaves the barrel of a gun.

That’s pretty simple, it doesn’t specify caliber or even the firearm, but just the speed of a bullet or round as it leaves a barrel.

Thus a pistol, a rifle, a shotgun, or a 5 inch naval gun has a muzzle velocity for a specific round.

It is also measured in a fixed distance over a specific time, such as feet per second, or even miles per hour.

If you look at your ammunition boxes and ballistics statistic sheets you will probably see indicated a value for muzzle velocity somewhere. 

It is one of the statistics that concern gun owners, especially those interested in ballistic data. 

Whether it’s hunting ammunition or self-defense ammunition, it is vital to check the muzzle velocity to identify if it’s suitable for your activities. 

Higher muzzle velocities are always best for hunting and self defense since they allow the bullet to maintain a trajectory and hit the target with a lot of energy.muzzle velocity, a bullet leaving a revolver

Factors That Affect Muzzle Velocity

Three main components affect muzzle velocity directly, and they include:

  • Bullet weight (grain)
  • Barrel length
  • Quantity and quality of the propellant

In simple terms;

The bullet weight means that a heavier grained bullet requires more force to move and accelerate as it leaves the barrel. A lighter grain attains higher speeds easier.

The quantity of propellant is obvious, and the army adage of ‘P for plenty’ means more propellant gives greater explosive force.

The barrel length matters as a firearm barrel is a closed system of sorts. When the cartridge fires the explosive force propels the round. The longer the barrel the more the force is directly behind the bullet, thus accelerating it for longer.

Propellant Quality And Quantity

Each ammunition round contains four main components, which are propellant powder, primer, bullet, and case. When the ammunition is fired, the primer ignites the propellant. 

When the propellant burns, it explodes in a controlled environment, which forces the bullet out through the barrel. 

High-quality propellants have a faster energy explosion, which increases the muzzle velocity.

Additionally, as you put a bigger amount of propellent behind a round the higher the muzzle velocity.

muzzle velocity, bullets leaving severl firearms

Bullet Weight (Grain)

The force required to move heavy objects needs to be higher than in lighter rounds to force the round down the barrel. 

Muzzle velocities of lighter bullets are faster than heavier bullets. For instance, 17 HMR rounds weigh 15 gr while 0.5 BMG rifles as massive as 750 gr. 

For example, with a 50 BMG 750 gr (49 g) Hornady has a muzzle velocity of 2,820 ft/s (860 m/s) but the lighter 655 gr (42 g) ADI has a muzzle velocity of 3,029 ft/s (923 m/s).

That’s a full 200 feet per second as the weight drops by nearly 100 grains (7g).

While heavier bullets travel relatively slower, they are less affected by wind.

Barrel Length

Longer barrels increase the muzzle velocity. 

When the round is fired, the primer is ignited, which in turn ignites the propellant powder. The resulting explosion expels the bullet through the barrel.

Longer barrels in and firearm increase the period for the chamber pressure to act on the bullets hence increasing the muzzle velocity. Guns with less barrel length have less distance for the gas to work on the bullet.

Here is an important point. Although barrels with short barrels have lower muzzle velocity, they create less friction, which reduces the heat involved.

muzzle velocity, a bullet leaving a pistol

What Is Muzzle Velocity Measured In?

Muzzle velocity is stated in feet per second (fps or ft/s). European brands use meter per second (mps or m/s). 

Black powder muskets muzzle velocities range from 120 m/s to 370 m/s while in modern high-performance rifles such as .204 Ruger, the velocity can exceed 1200m/s (3900ft/s).

A projectile velocity is highest as it leaves the muzzle and drops as it encounters air resistance.

Muzzle Velocity Formula – How To Calculate Muzzle Velocity

Muzzle velocity and energy are usually stamped on the ammo packaging. If you still need to know how to go about calculating the velocity, you are in the right place.

You can determine muzzle velocity by using the kinematics equation. You only need to know the acceleration of the bullet.

Kinematic Equation

v2=v02+2ax

V is the muzzle velocity

V0 is the initial velocity

X= distance traveled

Using a chronograph is the best way to determine muzzle velocity.

If the acceleration value is not provided, then you can still derive the muzzle velocity formula from the relationship between force, mass, and pressure.

P=F/A

F=ma, therefore a= Pπr2 ∕m

P= is the pressure

m = the mass

a=acceleration

Muzzle Velocity Calculator

Luckily, you can quickly determine the speed of a projectile by using a muzzle velocity calculator.

You only need to enter the initial velocity, distance traveled, and acceleration of the bullet.

You can proceed to determine the kinetic energy of the bullet using muzzle velocity and bullet weight. Muzzle energy is the main comparative element. It is the determining factor of picking one load over the other.

There’s a good calculator over at shooterscalculater.com.

muzzle velocity, a bullet leaving a semi automatic

Muzzle Velocity vs Muzzle Energy

Muzzle energy measures the kinetic energy of a projectile as it leaves the barrel usually measured in foot-pounds. 

Larger objects moving at a higher speed would have higher kinetic energy than a small slower object. 

On the other hand, muzzle velocity is the speed of the projectile as it leaves the barrel. In the US, the muzzle velocity is measured in feet per second.

What Is The Muzzle Velocity Of A Typical 9mm?

Muzzle velocity of 9 mm gun range from 950 fps to 1500 fps. The velocity of a typical 115 grain 9 mm round is 1180 fps. The velocity varies depending on the grain (a mass measurement) and the load of the round.

A larger bullet propels at 1000 fps. A bullet with 150 grain has a muzzle velocity of 2820 feet per second, and 180-grain ammo has a 2620 fps muzzle velocity.

Launching large bullets at high speed requires more energy. The larger the bullet, the slower the velocity.

Browning Ammunition

Round Type Weight Muzzle Energy Muzzle Velocity
9mm FMJ 115 356 ft-lb 1180 fps

 

Black Hills

9mm FMJ 115 336 ft-lb 1150 fps
9mm JHP 115 384 ft-lb 1150 fps
9mm JHP EP 115 368 ft-lb 1200 fps

 

Blazer

9mm JHP 115 335 ft-lb 1145 fps
9mm JHP 124 327 ft-lb 1090 fps
9mm JHP 147 295 ft-lb 950 fps

 

Extreme Shock

9mm AFR 85 442 ft-lb 1531 fps
9mm EPR 115 385 ft-lb 1182 fps
9mm FF 124 385 ft-lb 1182 fps

As you can see, despite some different cartridges, the known dimensions and grains of the rounds produce a reasonably similar muzzle velocity for a 9mm.

It seems they vary between 950 to around 1150 fps, which is more than enough to do serious damage, even at range.

Importance Of Muzzle Velocity

Signifies The Accuracy Of A Projectile

When the bullet is traveling at a higher velocity, it will drop less over a specific distance. This translates directly to the accuracy of the bullet. Besides the velocity, bullet weight, barrel length, rifling also plays a significant factor in determining the accuracy of the bullet.

Terminal Performance

Bullet designs have evolved from black powder musket ball models. Today, bullets expand and penetrate objects in different ways.

Muzzle velocity determines the performance of a bullet at an impact and how it transfers energy. The velocity and mass of a bullet determine the energy of a bullet. 

Bullets moving at high speed carry more energy and hence expand larger and penetrate deeper.

The longer the bullet travels before hitting the target, the more velocity it loses. Muzzle velocity is essential for hunters and people aiming for targets at long distances.

muzzle velocity, a bullet leaving a revolver

Advantages Of Higher Muzzle Velocity

Muzzle velocity determines how a bullet maintains a projectile and its performance after impact.

Straighter Trajectory

A bullet with a high muzzle velocity will travel at a relatively straighter projectile. On the other hand, an object that is traveling at a slow rate will drop quickly. As a result, faster bullets tend to be more reliable for downrange shooting.

High Terminal Performance

Faster bullets have a better terminal performance. Transfer of energy is one of the essential factors of terminal performance. When a bullet is traveling at high speed, it enhances energy at the impact.

Final Thoughts

Muzzle velocity is the speed of the bullet as once it leaves the barrel. 

Typically, a 9mm gun muzzle velocity ranges between 950 and 1150 fps depending on the bullet load and grain of the round. Also, the barrel length and quality of the propellant significantly affects the speed of the bullet.

Guns with long barrels produce higher muzzle velocity over there shorter barrel counterparts.

This translates to better range performance, which means that the bullet will penetrate deeper and expand larger at distance. 

If you are long-distance hunters and long instance rifle competitor, muzzle velocity will definitely be a major concern.

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