The AK-74 uses a 5.45×39mm cartridge, and its AK-74 bullet size centers on a 5.45 mm bullet diameter with specific case and overall length dimensions that influence accuracy, penetration, and recoil. This evergreen reference explains the key specs, how the bullet and cartridge are built, and how those details translate to real-world handling and terminal behavior. Readers gain a durable, fact-first foundation for understanding AK-74 ballistics without chasing short-lived trends.
Cartridge Basics: 5.45×39mm Overview
The AK-74 is designed around the 5.45×39mm cartridge, a compact, lightweight round developed in the Soviet Union to extend effective range and reduce recoil compared with older 7.62×39mm ammunition. The cartridge case holds a relatively small powder charge, and its bottlenecked shape helps feed reliably in the AK-74’s rotating bolt system. Overall length is capped by the magazine and bolt travel, making bullet profile and seating depth important for reliable function in semi-auto and select-fire configurations.
Case Dimensions
Case length is about 39.00 mm, with a base diameter close to 9.45 mm and a primer diameter typically matching standard small rifle primers. The bottleneck angle and shoulder geometry are optimized for headspace on the shoulder rather than the mouth, which supports consistent chambering. These dimensional choices also influence pressure curves and the suitability of the round for lightweight bullets aimed at flat trajectories.
Typical Powder Charge and Pressure
Factory loads use moderate powder charges that keep peak pressures within safe, standardized ranges for AK-platform actions. Lower chamber pressures reduce stress on the receiver and enable relatively lightweight rifles and barrels while maintaining adequate velocity for the bullet’s intended range and pattern. This balance underpins the AK-74’s reputation for controllable recoil and manageable wear over long service life.
Bullet Size and Dimensions
Bullet size for the AK-74 is defined primarily by a 5.45 mm nominal bullet diameter, with typical full-metal jacket (FMJ) bullets weighing around 67 grains and boat-tailed designs optimized for aerodynamic efficiency. Heavier 7N6-style military bullets approach 75 grains, while varmint and match loads may drop to the low 60-grain range to gain velocity. Bullet length and shank dimensions matter for magazine fit and feed geometry, especially in curved AK-74 magazines.
Bullet Types and Profiles
- Full Metal Jacket (FMJ): Standard military ball projectiles with a soft steel or lead core, designed for reliable feeding and predictable behavior at extended ranges.
- Hollow Point and Soft Point: Expanding bullets for hunting and law enforcement use, often tuned for controlled deformation in ballistic gelatin and medium game.
- Match and Varmint Loads: Lightweight, very flat-projecting bullets with boat tails and cannelures to stabilize in twist rates as fast as 1 in 9.5 inches or quicker.
Performance and Ballistics
Muzzle velocity varies by load, but typical 5.45×39mm ball ammunition delivers velocities near 880–900 m/s (about 2,900 fps) with the standard 67-grain bullet. Velocity drops modestly with range, and the bullet retains enough energy for practical medium-range engagements. The relatively small diameter and boat tail design limit drag, while terminal performance depends heavily on bullet construction; expansion and fragmentation improve with jacket thickness and nose cavity design.
Key Ballistic Factors
Twist rate, barrel length, and ambient conditions all influence stability and accuracy. Faster twist rates stabilize heavier bullets and lighter varmint loads, while slower rates can leave very light bullets marginally stable at longer distances. Shorter barrels reduce velocity slightly but remain effective for most AK-74 applications when paired with appropriate sighting and load selection.
Measurement Comparison: AK-74 vs Nearby Calibers
Comparing common intermediate cartridges clarifies how AK-74 bullet size and case capacity fit within the broader class. Metrics like bullet diameter, case length, and typical bullet weight help contextualize strengths and trade-offs for different roles.
| Cartridge | Bullet Diameter | Case Length | Typical Bullet Weight | Common Use |
|---|---|---|---|---|
| 5.45×39mm (AK-74) | 5.45 mm | 39.00 mm | 65–77 gr | Assault rifle, military, hunting |
| 5.56×45mm NATO (AR-15) | 5.56 mm | 44.65 mm | 55–77 gr | Assault rifle, police, varmint |
| 7.62×39mm (AKM) | 7.62 mm | 38.70 mm | 123–150 gr | Assault rifle, hunting, plinking |
| .300 Blackout | 7.62 mm | 33.80 mm | 100–220 gr | Suppressed, subsonic, medium game |
Practical Considerations for Shooters
Choosing bullets and loads for the AK-74 starts with confirming twist rate and magazine compatibility. Faster twist handles 62- to 77-grain bullets well, while slower twist favors mid-weight bullets around 60–67 grains for stability and manageable recoil. For reliable function, use bullets that feed smoothly in curved AK-74 magazines; very long, heavy bullets can increase jam risk in some rifles. Match loads with the intended purpose, whether plinking, hunting medium game, or training, and prioritize reputable ammunition from established manufacturers to ensure consistent headspacing and safe pressures.
Barrel and Gas System Interaction
Barrel length and contour influence velocity, accuracy, and heat management, while the gas system setting affects recoil and cycling reliability. A standard AK-74 barrel is often around 415 mm, offering a balance between velocity and maneuverability. Shorter barrels and reduced gas port sizes can raise felt recoil and increase muzzle blast, so choose setups that match your operating environment and primary roles. Proper maintenance of the gas piston and bore preserves accuracy and helps maintain consistent point of impact with different bullet weights.
Myths and Realities of Small Bullet Size
Some assume that a smaller bullet diameter inherently means less stopping power, but the 5.45×39mm’s performance comes from high velocity, flat trajectory, and terminal behavior tailored to the threat. Military ball ammo is designed for controlled tumbling after penetrating barriers, which can produce substantial wounding in live tissue. For hunting, selecting bullets designed for reliable expansion and weight retention improves ethical harvest. Understanding how AK-74 bullet size and velocity interact with target material helps set realistic expectations without leaning on exaggerated claims.
Summary and Recommendations
The AK-74 bullet size revolves around a 5.45 mm bullet in a 39 mm case, producing a compact, high-velocity round well suited to medium-range engagements. Match the bullet weight to your rifle’s twist and intended use, favor reputable manufacturers, and consider barrel length and gas setup to fine-tune performance. Consistent feeding, manageable recoil, and reliable accuracy make the AK-74 a durable platform for sport, training, and certain hunting applications when you align loads and components with practical needs.