7.62x39 vs 5.56 Rifle Caliber Comparison and What You Need To Know

7.62x39 vs 5.56 Rifle Caliber Comparison and What You Need To Know

When it comes to selecting a semi-automatic rifle cartridge, the 7.62 vs 5.56 debate is always at the forefront of the conversation.

Both calibers have been proven on the battlefield beginning in Vietnam and all the way through the Global War on Terror. As a result, they are two of the most popular rifle calibers in use today.

Almost every military around the world uses one of these calibers for their primary battle rifle. Why? The terminal ballistics and effectiveness in close engagements as well as distance engagements.

Let’s take a closer look at this caliber comparison that defined world conflict since the Cold War; 7.62x39 vs 5.56.

Is 7.62 or 5.56 Better?

Whether you’re designing your next AR build or cruising your local gun show, you’ve seen a lot of 7.76x39 and 5.56 rifles and ammunition.

These two calibers are some of the most widely available ammunition choices for semi-automatic rifles. They are readily available for good reason; the military and law enforcement use them. 

With that said, is 7.62 or 5.56 better? And does it matter?

7.62×39 ammo was established towards the end of WWII in 194 by Russia. It was designed to be an intermediate-range cartridge and gained a lot of traction once Russia designed the AK-47 and put it into military use.

Not long after that, China adopted the 7.62x39 as well as Africa and South America. 7.62×39 chambered weapons and the ammunition proliferated from that point forward.

As far as ammunition choices for 7.62x39 go, not much has changed over the course of its history. Most commercially available loads use a bullet weight of roughly 120 grains, and the bulk of the ammunition is full metal jacket.

The 5.56 NATO cartridge (5.56x45) was the successor to the 7.62x39 in terms of military use. It became the infantry cartridge of choice during the Vietnam War and remained so through the Global War on Terror. Originating from the commercial .223 Remington cartridge, minor changes were made during the development of the 5.56 NATO cartridge.

After its initial growing pains, the 5.56 cartridge proved to be incredibly successful. The round serves to this day in the hands of most U.S. troops and law enforcement officers. Paired with America’s favorite rifle, the AR-15, 5.56 has become one of the most popular rounds in the nation.

Another point to consider when comparing these cartridges is the cost of ammunition. While steel cased 5.56 is roughly the same as steel case 7.62x39mm, brass cased 5.56 NATO has a considerable difference in price. You can find both calibers for ‘reasonable’ prices, you just need to know where to look. 

Understanding the ballistics of each round will help you determine which round is best suited for your application as well as what load within each caliber is best. Once that is determined, it’s time to go shopping.

What are the ballistic characteristics of a 7.62 AK round vs a 5.56 AR round?

The 5.56mm NATO and the 7.62x39mm were both developed as military cartridges in the 1960s, and have remained in the public arena ever since. The increased energy and heavier bullet weights of the 7.62x39mm allow it to bring down larger targets at distance, while the higher velocity and lighter recoiling 5.56 is more preferable for shooters targeting smaller targets at the same distances. 

There is more to it, though, than just having a heavier mass hit harder. 

Let’s take a look at the differences in velocity, energy on target, and trajectory (bullet drop). The most important of these three being velocity, since that will dictate how much energy the bullet will have on target and how much drop will occur in flight.

Velocity

Velocity is one of the main attractions of the smaller 5.56mm NATO round. For the sake of ballistics comparison, let’s look at a 62 grain 5.56 NATO versus a 123 grain 7.62x39

At the muzzle, the 62 grain 5.56 is traveling 710 feet per second faster than the 7.62x39. 

At 300 yards, velocity of the 5.56 has decreased slightly to 560 feet per second faster. 

At 500 yards, velocity of the 5.56 has decreased, but still in the lead at 412 feet per second faster. Even though this is an impressive lead, it loses its energy on target a bit faster than the 7.62x39.

Energy on Target

While a lighter bullet is a benefit for velocity, a heavier bullet brings more energy and more stopping power. This is where the 7.62x39 pulls ahead of the 5.56. 

At the muzzle, the 7.62x39 has an additional 219 foot-pounds of energy over the 5.56. 

At 300 yards, the energy on target has narrowed to 39 foot-pounds more than the 5.56.

At 500 yards, the 7.62x39 has just 27 foot-pounds more energy than the 5.56.

Trajectory (Bullet Drop)

Along with higher velocity, the 5.56 also maintains a flatter trajectory. For this comparison we’re looking at a 77 grain 5.56 versus a 123 grain 7.62x39 with a 200 yard zero. 

At 300 yards, the 5.56 will drop 8.6 inches compared to the 14.8 inches of the 7.62x39. 

At 400 yards, the 5.56 will drop 25.6 inches compared to 45.2 inch drop of the 7.62x39. 

At 500 yards, the 5.56 drops 53.5 inches while the 7.62x39 drops 96.6 inches.

5.56 vs 7.62x39 Ballistics Chart

62-grain 5.56 vs 123-grain 7.62x39

 Distance 62-grain 5.56 NATO 123-grain 7.62x39
Muzzle Velocity 3,060 feet-per-second 2,350 feet-per-second
100 Yards (velocity) 2,714  2,053
200 Yards (velocity) 2,394 1,780
300 Yards (velocity) 2,095 1,535
400 Yards (velocity) 1,820 1,324
500 Yards (velocity) 1,571 1,159
Muzzle Energy 1,289 foot-pounds 1,580 foot-pounds
100 Yards (energy) 1,014 1,151
200 Yards (energy) 789 865
300 Yards (energy) 604 643
400 Yards (energy) 456 479
500 Yards (energy) 340 367

 

As you can see from the chart above, the playing field evens out a bit with regards to energy on target once you get out to 300 yards and beyond.

What Level Body Armor Stop 5.56?

Level III and Level IV armor plates are built to withstand and defeat rifle rounds. 

Level III polyethylene plates are lightweight and can stop rifle bullets up to and including 7.62x39. Additionally, by adding a ceramic face, polyethylene plates can be certified to Level IV and will stop steel core rounds.

Can Level 3 Armor Stop 5.56?

Level III will stop most 5.56 and 7.62 rounds, but will not defeat military-grade armor-piercing ammo. 

For example, an 62-grain steel core M855 will defeat a Level III armor system. Level III armor will, however, defeat a standard 55-grain 5.56 NATO round.

How Can ShotStop Help?

ShotStop® sells both NIJ Level 3 and Level IV body armor that meets and exceeds all standard testing procedures. 

Even though NIJ tests Level 3 armor to stop an M80 bullet, our Duritium® Level III+PA and PS plates will stop a 7.62x39 and 5.56 NATO (M193).

This means that our Level 3+ plates will stop 6 rounds of the most common calibers fired from an AK-47 and an AR-15 platform.

Our Duritium® Level IV+HA plate is the lightest, thinnest, and most comfortable multi-curve plate in production. At just 4.5 lbs per plate for the standard 10” x12” plate, we offer each of our plates in either SAPI, Full, or Shooters Cut. 

We’re excited to get to know our future customers and look forward to serving our community with the best possible ballistic protection. If you have questions please contact us at sales@shotstop.com.


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