The 308 Winchester & 556 ammo are the two most popular battle-proven cartridges used by the U.S. Military and its NATO allies.
The debate between 556 vs 308 has been going on for over 60 years among law enforcement, civilian marksman, and military shooters.
Both rounds have unique features, advantages, and disadvantages, and it can be challenging to determine which is the best choice for you.
In this blog post, we will compare and contrast the 556 vs 308 cartridges, looking at their ballistics, uses, and other factors to help you make an informed decision.
Whether you are an experienced shooter or a novice, understanding the differences between these calibers is essential before choosing the best one for your needs.
You can see our previous comparison post about : 308 Vs 338 Lapua & 556 vs 223. This will be helpful to choose the best lever action rifle calibers.
Let's get back to the topic….
| Specifications | 308 Win | 5.56 NATO |
| Type | Rifle | Rifle, carbine, DMR, and LMG |
| Place of origin | United States | Belgium |
| Parent case | .300 Savage | .223 Remington (M193) |
| Case type | Rimless, bottleneck | Rimless tapered, bottleneck |
| Bullet diameter | 0.308 in (7.82 mm) | 5.70 mm (0.224 in) |
| Neck diameter | 0.3433 in (8.72 mm) | 6.43 mm (0.253 in) |
| Case length | 2.015 in (51.2 mm) | 44.70 mm (1.760 in) |
| Overall length | 2.800 in (71.1 mm) | 57.40 mm (2.260 in) |
| Case capacity | 56 gr H2O (3.6 cm3) | 1.85 cm3 (28.5 gr H2O) |
| Maximum pressure | 62,000 psi (430 MPa) | 380.00 MPa (55,114 psi) |
308 (7.62x51mm NATO) has been a good choice for long-range shooting for many decades. It was introduced in the 1950s to fulfill the military requirements for a round similar to the stopping power of the beloved 30-06 & needed something with much stopping power in a shorter, more manageable cartridge.
The .308 Winchester cartridge was developed by Winchester in 1952, primarily as a hunting cartridge.
The .308 Winchester quickly gained popularity in the shooting community due to its versatility and accuracy, and it is now widely used for hunting, target shooting, and military and law enforcement applications.
The 5.56 cartridge, sometimes called 5.56x45mm NATO, is more frequently found in assault rifles and carbines.
It was first utilized by militaries and police enforcement organizations worldwide, particularly the American military, in the 1960s to replace the .308 Winchester and the 7.62x51mm NATO cartridge.
The goal was to create a lighter, smaller, and more manageable cartridge for the new M16 rifle.
The .556 caliber is renowned for its high velocity and low recoil, which make it simple to operate and enable rapid fire.
The 5.56x45mm NATO cartridge has become the standard cartridge for many military and law enforcement agencies worldwide due to its lighter weight, higher capacity magazines, and lower recoil, allowing for faster and more accurate follow-up shots.
The .308 Winchester and the 5.56 NATO are popular cartridges used in firearms today. Here's a comparison of their bullet size and capacity:
The .308 Winchester cartridge, also known as 7.62x51mm NATO, comes in grain weights from the 120s to the 180s, with the most common hunting loads being 150 to 180 grains. These are large and perfect for North American big game like White Tail deer and Black Bear.
While the 5.56 NATO cartridges are more limited from 55 to 77 grains, several types of “5.56” cartridges have higher bullet weights from 40 to 80 grains. These are great for hunting smaller or varmint games and competitions with targets at distances further than 300 yards.
Regarding capacity, the .308 Winchester cartridge typically holds fewer rounds than the 5.56 NATO. This is because the larger bullet size of the .308 Winchester requires more space in the cartridge, leaving less room for powder and resulting in a smaller capacity.
On the other hand, the smaller bullet size of the 5.56 NATO allows for a larger capacity, meaning that firearms chambered in 5.56 NATO can typically hold more rounds than those chambered in .308 Winchester.
The .308 Winchester is generally considered a more powerful cartridge with better long-range capabilities. At the same time, the 5.56 NATO is a lighter and more compact cartridge with less recoil and better armor penetration.
| Feature | 308 Winchester | 5.56x45mm NATO |
| Diameter | 7.62mm | 5.56mm |
| Weight | 150-180 grains | 55-77 grains |
| Muzzle velocity | 2,700-2,900 fps | 2,800-3,100 fps |
The 5.56 NATO and the 308 Winchester are widely used cartridges in weapons for various uses. Their accuracy may suffer as a result of their varied performance and attributes.
The 308 Winchester is more accurate than the 5.56 in terms of accuracy. The 308 Winchester bullet is more resistant to wind drift and other environmental influences because it is heavier and larger. Because of its higher muzzle velocity, the 308 Winchester can travel farther and make more accurate hits on targets.
However, the 5.56 may also be extremely accurate, particularly when using modern ammo. According to some shooters, the 5.56 is more accurate than the 308 at short ranges.
Ultimately, the accuracy of any ammunition depends on various variables, including the rifle's quality, the shooter's skill, and the shot being used.
The 308 Winchester is usually considered for its higher performance than the 5.56. This is so because the 308 Winchester bullet has kinetic energy that will be helpful to penetrate deeper into targets. The 308 Winchester may also hit targets with greater force due to its increased muzzle velocity.
The 5.56 can be extremely useful, particularly in military and police enforcement. The 5.56 bullet is designed to tumble after hitting the target, causing more damage to the target's internal organs. Additionally, 5.56 is a lighter round, allowing it to be fired from more lightweight rifles.
| Feature | 308 Winchester | 5.56x45mm NATO |
| Accuracy | More accurate | Less accurate |
| Performance | More powerful | Less powerful |
| Effective range | Longer effective range | Shorter effective range |
The .308 Winchester has more recoil than the 5.56x45mm NATO cartridge. This is due to the .308's heavier bullet weight and larger powder charge, which generates more energy and, therefore, more recoil.
The 5.56 cartridge, on the other hand, is lighter and generates less recoil, making it easier to shoot quickly and accurately. This can be particularly advantageous when rapid follow-up shots are needed, such as in military or law enforcement applications.
In terms of uses, the 308 Winchester and 5.56x45mm NATO are two of the most well-liked rifle cartridges in the world. But they are designed for different applications.
The 308 Winchester cartridge can be used in a wide range of situations, such as:
The 5.56x45mm NATO cartridge, which is smaller and lighter than the 308 Winchester, is frequently employed in the following situations:
If you are looking for a cartridge that is powerful and accurate for long-range shooting, then the 308 Winchester is a good option.
If you are looking for a cartridge that is lightweight and easy to control, then the 5.56 is a good choice.
Many different rifles are available in both .308 Winchester and 5.56x45mm NATO, ranging from entry-level models to high-end precision rifles. Here are some examples of rifles chambered in each cartridge
These are just a few examples of the many different rifles available in each cartridge. When selecting a gun, it's important to consider your intended use, personal preferences, budget, and factors such as reliability, accuracy, and ergonomics.
The price and availability of ammunition for .308 Winchester and 5.56x45mm NATO can vary depending on several factors, including the brand, type of bullet, and local market conditions. Here are some general trends to consider:
Overall, the cost and availability of ammunition for .308 Winchester and 5.56x45mm NATO can vary depending on many factors, so it's important to do your research and shop around to find the best deals.
Here are some general pros and cons of the .308 Winchester and 5.56x45mm NATO cartridges:
The .308 Winchester is better suited for long-range shooting and hunting, while 5.56x45mm NATO is better suited for tactical situations and general-purpose shooting.
In the end, the choice between 308 Vs. 5.56 depends on individual preference, as both calibers have their advantages & disadvantages.
While 5.56mm rounds may offer lower recoil and less concussion for the shooter and those nearby, 308mm rounds may be necessary for situations requiring greater stopping power.
Ans: No, it would be best never to attempt to shoot a cartridge in a not specifically chambered firearm. The .308 Winchester cartridge is larger and more powerful than the 5.56x45mm NATO cartridge, and trying to fire it in a rifle chambered for 5.56x45mm NATO can result in serious injury or death.
Ans: Generally, the .308 Winchester cartridge is better suited for long-range shooting due to its higher ballistic coefficient and greater energy at longer distances.
Ans: The .308 Winchester cartridge is generally better suited for hunting large game such as deer, elk, and bear due to its greater energy and stopping power.
Ans: The 5.56x45mm NATO cartridge is more widely used by military and law enforcement agencies worldwide, while the .308 Winchester cartridge is more popular among civilian hunters and long-range shooters.
Ans: No, you cannot convert a rifle chambered in .308 Winchester to shoot 5.56x45mm NATO ammunition. The cartridges have different dimensions and operating pressures, and attempting to convert a gun to fire another cartridge can result in serious injury or death.
Ans: In most cases, yes. The .223 Remington cartridge is similar in dimensions to the 5.56x45mm NATO cartridge, and most rifles chambered for 5.56x45mm NATO can also safely shoot .223 Remington ammunition. However, it's always important to consult the owner's manual and follow the manufacturer's recommendations for ammo.
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