Kalashnikov assault rifle bullet speed: from 715 to 900 m/s - what affects the performance?

The Kalashnikov assault rifle is a legendary weapon, known throughout the world for its reliability and simplicity. But when it comes to ballistic characteristics, many are interested in specific numbers: what is the bullet speed of the AK-47, AK-74 or modern modifications? This parameter directly affects the firing range, penetration power and hit accuracy.

In this article we will look not only basic bullet speed values in meters per second (m/s) for different AK models, but also factors that can change this indicator. You will learn why the speed of a bullet from the same machine gun can differ by 10-15% depending on conditions, how the length of the barrel, the type of cartridge and even the ambient temperature affect it. And for those who are planning to purchase or upgrade weapons, we have prepared comparative tables and practical advice.

If you have ever held a Kalashnikov assault rifle in your hands or are simply interested in military equipment, this material will help you understand the intricacies of its ballistics. Not everyone knows that the speed of a bullet AK-74 almost 200 m/s higher than AK-47, and modern cartridges for AK-12 can reach speeds up to 900 m/s - and this is not the limit. But first things first.

Base bullet speed of AK-47: 715 m/s - myth or reality?

Classic AK-47, adopted into service in 1949, uses the cartridge 7.62×39 mm. According to the official technical specifications, muzzle velocity (measured at a distance of 1 meter from the trunk cut) is 715 m/s. However, this value is an average and may vary depending on the batch of ammunition, barrel wear and other factors.

In practice, bullet speed AK-47 in real shooting conditions it often turns out to be in the range 680–730 m/s. Why is this happening? The point is that:

• 🔹 Barrel length: The standard AK-47 barrel is 415 mm long. Shortened versions (eg AKS-74U) lose up to 10-15% of the initial speed due to the shorter acceleration time of the bullet.
• 🔹 Powder temperature: At low temperatures (below -10°C), bullet speed can drop by 20-30 m/s as the powder burns less efficiently.
• 🔹 Ammo quality: Cartridges from different manufacturers (for example, Russian 7N6 or Chinese Type 56) can produce a spread of 30-50 m/s.

Important: The initial velocity of a bullet is not the same as the velocity along the trajectory. Already at a distance of 300 meters, an AK-47 bullet loses up to 30% of its speed due to air resistance.

Speed comparison: AK-47 vs AK-74 vs AK-12

Transfer from cartridge 7.62×39 mm on 5.45×39 mm in AK-74 (1974) was a revolution in ballistics. The new ammunition was lighter (3.4 g versus 7.9 g for the 7.62 mm bullet) and had a higher initial velocity - 900 m/s versus 715 m/s for the AK-47. This provided several key benefits:

• 🎯 Flatter trajectory (the bullet flies “straighter”), which simplifies aiming at long distances.
• 💥 Increased penetrating power at distances of up to 500 meters due to high kinetic energy.
• 🔄 Less recoil, which improves the accuracy of burst fire.

Modern AK-12 can use both types of cartridges, but with a cartridge 5.45×39 mm its speed characteristics are close to AK-74 - about 880–910 m/s. At the same time, modifications with an elongated barrel (for example, AK-12K) can issue up to 920 m/s.

Interesting fact: cartridge 5.45×39 mm was designed specifically to increase the muzzle velocity of the bullet. Its case has a steeper cone, which allows for more efficient use of powder gases. However, when shooting at a distance of over 600 meters, the bullet loses speed faster than the 7.62 mm due to its lower mass.

What affects bullet speed: 5 key factors

Even for the same machine gun, the bullet speed can differ by 50-100 m/s. Let's look at the main factors that influence this:

1. Barrel length

The longer the barrel, the longer the powder gases take to accelerate the bullet. For example:

• 📏 AK-47 (415 mm) - 715 m/s
• 📏 PKK (590 mm) - 745 m/s
• 📏 AKS-74U (206 mm) - 735 m/s (despite the 5.45×39 mm cartridge!)

2. Bullet type and weight

Light bullets accelerate faster, but lose speed along the trajectory. For example:

• 🔘 Bullet 7N6 (5.45 mm, 3.4 g) - 900 m/s
• 🔘 Bullet 7N22 (5.45 mm, 3.6 g) - 880 m/s (due to greater mass)
• 🔘 PS bullet (7.62 mm, 7.9 g) - 715 m/s

3. Temperature and humidity

At a temperature of -30°C, bullet speed can drop by 50-70 m/s compared to shooting at +20°C. This is due to changes in the properties of gunpowder. Humidity also has an effect: high humidity can dampen the powder, which reduces the pressure in the barrel.

4. Barrel wear

After 10-15 thousand shots, the AK barrel begins to “break” - its internal diameter increases, which leads to gas breakthrough and a drop in bullet speed by 3-5%.

5. Ammo quality

Military-grade cartridges (for example, 7N6 or 7N10) provide a stable velocity with a spread of no more than 1%. Civilian or artisanal ammunition can have a spread of up to 10-15%.

⚠️ Attention: Using cartridges with an excessive powder charge (so-called "reinforced" ammunition) can lead to barrel rupture. For example, 7.62x39 mm cartridges with a charge designed for an SKS rifle are not intended for AK assault rifles due to higher pressure.

How to measure bullet speed: methods and equipment

To accurately measure bullet speed, special instruments are used - chronographs. They come in several types:

• 📊 Optical chronographs: Record the time it takes a bullet to pass between two light sensors. Accuracy - ±0.5%.
• 📡 Radar chronographs: Uses the Doppler effect to measure velocity. Accuracy - ±0.2%, but are more expensive.
• 🎯 Ballistic barrels: Laboratory equipment that measures speed using pressure sensors. Accuracy - ±0.1%.

Portable optical chronographs such as MagnetoSpeed or Caldwell Ballistic Precision. They are attached to the barrel and synchronized with a smartphone to record data.

The measurement process looks like this:

1. Place the chronograph at a distance of 1 meter from the end of the barrel.
2. Fire a series of 5-10 shots (to average the result).
3. Record the minimum, maximum and average speed.

⚠️ Attention: When measuring bullet velocity on the range, make sure the chronograph is out of the line of fire. Optical sensors can be damaged by shrapnel or ricochet.

Practical Implications of Bullet Velocity for the Shooter

Why is it important for an ordinary shooter or hunter to know the bullet speed of his machine gun? This depends on:

• 🎯 Firing accuracy: The higher the speed, the less the influence of the wind on the trajectory. For example, at a speed of 900 m/s, a side wind of 5 m/s moves the bullet by 300 mm at a distance of 500 m, and at 715 m/s - by 450 mm.
• 💥 Penetrating power: Bullet kinetic energy (E = mv²/2) depends on the squared speed. The AK-74 bullet (900 m/s) has an energy of ~1500 J, and the AK-47 (715 m/s) has an energy of ~1200 J.
• 🔄 Recoil: Lighter and faster bullets (5.45 mm) produce less recoil, which improves weapon control during automatic shooting.

For hunting or sport shooting, it is important to select cartridges with optimal speed:

• 🦌 For medium game (boar, deer), 7.62×39 mm with a speed of 715 m/s is suitable - sufficient energy for a reliable kill.
• 🐺 For small game or varmint (gophers, hares) 5.45×39 mm is better - high speed ensures less damage to the skin.
• 🎯 For long-range shots (over 600 m), heavy bullets with lower speed but better ballistics are preferred.

Myths and misconceptions about AK bullet speed

There are many myths surrounding the Kalashnikov assault rifle related to its ballistics. Let's look at the most common ones:

Myth 1: "The faster the bullet speed, the better"

In fact, excessively high speed can be harmful:

• 🔥 Barrel wear increases (especially when firing in bursts).
• 💨 The bullet loses energy faster along the trajectory due to air resistance.
• 🎯 At distances over 300 m, “fast” light bullets (5.45 mm) can be exactly inferior to heavy ones (7.62 mm).

Myth 2: "Bullet speed does not depend on temperature"

This is not true. When shooting in winter (below -20°C), the bullet speed may drop by 5-7%. For example, for AK-74 this means a drop from 900 m/s to 830–850 m/s. This affects the trajectory and requires adjustment of the sight.

Myth 3: “All 7.62x39mm cartridges are the same”

In fact, even within the same caliber, the speed may differ:

• 🔹 Patron M43 (USSR, 1943) - 715 m/s
• 🔹 Patron 7N23 (Russia, 2010s) - 740 m/s (increased charge)
• 🔹 Patron Type 56 (China) - 690–720 m/s (depending on the batch)

Myth 4: "Shorter AKs (for example, AKS-74U) have the same bullet speed"

In practice, a shortened barrel reduces speed by 15-20%. For example, AKS-74U (206 mm barrel) produces only 735 m/s instead of 900 m/s for the full-size one AK-74.

FAQ: Frequently asked questions about AK bullet speed