Whether building an AR-15, cruising a gun show, or staring at a wall of ammunition at your local gun shop, most shooters have come across or at least heard of 7.62x39mm and 5.56x45mm.
These two cartridges are some of the most abundantly available ammunition choices on the planet. Why is that? Well, most major and minor military forces worldwide use one of these two cartridges.
But which is better, and does it matter?
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A Brief History: Forged in Warfare
7.62.x39
The 7.62×39 cartridge was established in 1944, towards the end of WWII, by the Russian government.
It was designed to be an intermediate-range cartridge that gave soldiers a middle ground between full-powered rifle cartridges and pistol-caliber submachine gun cartridges.
The round gained a lot of traction once the Russian government adopted the now-iconic AK-47 and put it into military use.
You can read more about the history of the AK, 7.62×39, and learn more in our AK-47 Buyer’s Guide and our Best AK-47 Ammo articles!
The AK-47 proved to be a simple, affordable, and effective weapon. It has been fielded by over 100 countries, including other world powers like China. Owing to the AK’s widespread popularity, 7.62×39 ammunition became prolific worldwide.
As far as ammunition choices for the 7.62x39mm go, it has always been relatively limited due to the design of the cartridge.
Most commercial loads use a bullet weight of just over 120 grains, and the bulk of the ammunition is either full metal jackets, hollow points, or pointed soft points. While less common, heavier 180-200gr subsonic rounds are also available.
Unfortunately, 7.62x39mm uses .310-inch diameter bullets rather than the industry standard .308-inch diameter. This means a much smaller range of bullet choices from modern ammo manufacturers.
Additionally, the majority of 7.62×39 is steel-cased, and brass casings aren’t as plentiful. This means that despite the round’s popularity, it isn’t great for those who reload ammo.
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Prices accurate at time of writing
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5.56×45
The 5.56x45mm, or 5.56 NATO, was originally derived from the commercial .223 Remington cartridge.
Similar to the 7.62×39, the concept of the 5.56 was that it was smaller than the previous full-powered 7.62×51/.308 cartridge. This meant troops in the field could carry more ammunition in a gun that was easier to control.
With the United States being the world’s leading military force, their adoption of the M16 meant that various allied countries would adopt or create firearms chambered in 5.56×45 to be able to share ammo supplies during wartime. As such, the round was adopted by NATO, hence the designation 5.56 NATO.
Unlike the 7.62×39, projectile weights for the 5.56 NATO have changed a good bit throughout its history.
Since the .224″ caliber projectile is popular with the .223 Remington, reloaders can really fine-tune a cartridge for maximum accuracy and effectiveness at the range or in the field.
Typical bullet weights can range from 35 to 85 grains, with some specialized rounds falling outside that range.
For those that don’t reload, there is a cornucopia of choices between 5.56 NATO and .223 Remington factory cartridges. Check out our complete guide to our favorite 5.56/.223 ammo.
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Prices accurate at time of writing
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Does Size Matter?
Foregoing the innuendos and “that’s what she said” jokes, does the concept of smaller calibers hold water when it comes to lethality?
In my opinion, and the opinion of militaries across the globe, it does. This is due to one crucial element — velocity.
Here is a quick physics lesson — kinetic energy equals half of the mass multiplied by velocity squared or K.E. = 1/2 mv^2. Velocity tends to be an important factor when calculating kinetic energy on a target, considering it increases exponentially.
Mass is obviously important, but the faster it goes, the more potential damage it can do. Also, with velocity comes further effective ranges.
When you look into the ballistics of a common 123-grain FMJ round, the muzzle velocity is around 2,350 feet per second.
It’s a reasonable velocity for a short-range cartridge, but the round has a mediocre ballistic coefficient (ability to overcome air resistance). With a 100-yard zero, at 300 yards, there is 26 inches of drop, and it is retaining 550 ft/lbs of energy.
Now when we look at a 5.56 NATO with a 55-grain M193 cartridge, muzzle velocity is around 3,000 feet per second, and at 300 yards, there are only 10 inches of drop with a 100-yard zero. The kinetic energy is roughly the same at around 520 ft/lbs of energy.
This is where projectile variety comes into play.
With a 5.56 Mk262 70-grain OTM load, muzzle velocity is roughly 2700 feet per second. With a 100-yard zero, there is only 12-inches of drop. However, kinetic energy then jumps up to a whopping 700 ft/lbs. I’d say the 5.56 NATO is taking the lead!
How Hard Does It Hit…Your Wallet?
The price of ammunition is definitely something to consider when comparing different cartridges.
While steel-cased 5.56/.223 costs roughly the same as steel-cased 7.62x39mm, at around $0.35 to $0.40/per round; it is a different story when it comes to brass-cased ammo.
Post-pandemic, most shooters will be looking at around $0.38 to $0.60/rd for standard brass 5.56 ammo. As mentioned before, brass 7.62×39 ammo is fairly uncommon, and you are looking at around $0.50 to $0.70 /rd.
While availability used to be pretty equal between these two, sanctions against Russia, pandemic-related supply chain issues, and other import bans have caused 7.62×39 to see a notable decline in availability.
Although 7.62×39 is still readily available in most places, the number of different brands you will see on shelves has been drastically reduced.
Ammo disappeared during the pandemic, and it took a while for things to start trickling back in. But when push came to shove, the AR-15 is “America’s Rifle,” which means everyone wanted 5.56 NATO back first.
With 5.56 production far outpacing that of 7.62×39 in 2022, it is no longer cheaper or easier to blast away with your AK. With the prices hovering close to each other, 5.56 NATO gets the nod here due to sheer availability.
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Prices accurate at time of writing
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Variety Is The Spice Of Life
When you dive into the depths of what rifle to get, it starts to get a bit dicey. The choices are plenty, and ultimately, it is dependent on the shooter’s preference.
Aside from your classic AR-15 vs. AK-47 debate, there are a good amount of other rifles chambered in each caliber. There is no right or wrong answer here; it is down to what you want.
Heck, you can even get an AR-15 in 7.62×39 or go for an AK in 5.56 NATO. They even have hybrid guns like the PSA KS-47, which is an AR-15 that takes AK mags. The choices are vast, so have fun!
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Prices accurate at time of writing
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Final Thoughts
So, in the end, does it really matter?
The choice is ultimately up to you and what you want in your rifle. With market prices shifting due to several factors, there isn’t a definitive answer as to which is cheaper. As for effectiveness? It depends on your mission and what you plan to do.
Either way, the next time you are on the range, put casings on the ground and have fun!
Which caliber are you a fan of? Do you like both…maybe neither? Let us know in the comments below! Interested in other calibers? Be sure to check out our Ammo & Reloading section for more info.
50 Leave a Reply
The bullet that does what you want AND need is the best bullet to use. Mystery solved.
PewPew Editors - please stop playing "moderate", "independent" voter without an opinion. I know that's how it goes in California, but not out here in flyover country. Take a stance. Be somebody. Say something. Boldly. For example, "our opinion is that 5.56 is better than 7.62 x 39, and because..." and then back your $h!t up with some well-researched facts. I get tired of reading articles that, at the end, say something like... "the choice is up to you" or "it's a matter of preference." Of course it's a matter of preference, but preference should be guided by good counsel.
No. if you want biased opinions on firearm related stuff, there's plenty of places to go for that. What PPT tries do to is separate from that to be approachable for EVERYONE, not just the people YOU agree with. The staff at PPT are aware they are not the definitive authority on everything gun-related. Vent somewhere else.
I believe that 762x39 wasn’t made to perform past 300 yards because the Communist Bloc expected to do battle with the west in the forrests of Europe and the jungles of Asia. Isn’t that why they shoot the 762x51 in their Draganov sniper rifles because it will reach out and touch you and not the 762x39?
I I have both ammunitions and my Pre-Ban Chinese Type 56 under folder (which is sweet)chambered in 762x39 can hit a body size target at 200 yards my Sig 516 chambered in 556x45 drives tacks at that range.
Flip a coin and choose your poison. They will both perform and get the job done in an urban environment.
Correction: Dragunov uses 7.62x54mm cartridge.
Has there ever been a conflict in history, in which both weapons were use, where an AR has won against an AK? Pretty sure no.
Have a AR rifle in 7.62x39 and a AR pistol in 7.62x39 because of both price per round and 200 yard or less knock down power. I would eventually like a .223 Wylde upper for longer distance target shooting though as well a an eventual LR-308. The 7.62's are a blast to shoot, no pun intended.
I encourage everyone to own both if possible. They each have their benefits, depending on the scenario.
can't agree more. own both AKs and ARs and wouldn't have it any other way.
Sig 556R all day
In a real world war the 5.56 won't beat a 7.62 knock down power because most fire fight are fought well with in 200 yards anyways...the closer the better for the 7.62...plus the request for a better cartridge than the 5.56 by the U.S special forces...do your home work!
Tells people to do their homework.
Uses senseless terms such as "knock down power".
lol
I have built 2 AR15 platform chambered in 7.62x9. I have a 10.5 inch pistol and a 14.5 inch barrel rifle. It takes a minimal mount of tweaking to get them cycling perfect but then it is awesome. There is plenty of inexpensive ammo and there is hunting rounds. I have shot holes through 1/4 inch steel at 100 yards and I have read that many white tail and large hogs have been taken with this caliber. If SHTF there would still be ammo for 7.62x39. In todays ammo shortage it is available. I would want a heavier grain 30 caliber type rifle for my general purpose and a great SHTF rifle. An AR15 running 7.62x39 is exactly what Colonel Jeff Cooper was talking about for an ideal scout style rifle.
I use the AK47 with 7.62x39 for one simple reason. If we are ever attacked by an enemy, foreign or domestic, they will probably use the 7.62x39. 5.56 requires rear supply lines, while with 7.62x39 every enemy combatant is a potential resupply point...
Yes but if our own government or nato allies ends up being the problem 5.56 will be at every supply point.
Great minds thinking alike hahaha
As far as the sweetest shooting 7.62x39 one should try a quality SKS. I have tried different ones, the Chinese ones are less accurate and feel like rattletraps as the low end AK's would. However, get a good one, either Century or some com-bloc country like Russian made they are sweet as butter. More accurate than even a good AK like Palmetto or Aresnal, less recoil and just amazingly pointable and easy. I understand the capacity is only 10 and the loading isn't as quick or ergonomic with the stripper clips but in a SHTF, defensive or even hunting scenario I wouldn't feel under gunned with an SKS unless I was in a really bad, war-like scenario or facing huge, dangerous game. I n both situations it would be my fault for getting into them with an SKS but for most scenarios it's a joy to shoot. It's less noisy and concussive than an AR. Especially for a novice shooter I might prefer it to the AR or AK just in terms of overall dynamics if using just open sights. My older son swears by one and I cannot fault him for it.
You should really look at getting the modified 40rd AK type mags for your SKS, makes shooting less work and more play.
I chose an AR-15 when I was new to the sport years ago, so I just never got the itch to own an AK. The key factor for me has always been, accuracy. When the target is in the cross hair, I just got to believe in my rifle’s accuracy. So if I do my part, I will just feel much more confident, and better about the shot. i would never question the AK rifles battle worthy reputation, but if I can hit the target where I want to hit it, I would not need a bigger slower boolit. i just bought a 6.5 Grendel. It is most amazing. Heavier than a 5.56and faster than an AK. So to answer the question, I’d rather have an AR platform using a type 2 Grendel setup. It is even more accurate than a 5.56 and more energy than an AK 7.62x39. My grendel with an 18 inch barrel rings steel easily at 5-800 yards.
Many folks like the AK which is considered
more dirt tolerant than the AR platform.
I carried the M16 in Vietnam and I have a couple of AR platform rifles today. I have
shot AK’s , my preference is the AR /M16.
In my estimation the AR is a better shooting
firearm and has better accuracy at distance.
I wouldn’t want to be shot with either though.
I've owned both, the AR15 in X39 is the way to go. You can run a super short barrel and still have good performance. FYI I sold the "AK chambered in 556" (saiga 223).
I’d like to have both. I have an AR15. Saving up for an AK47. Good read. Thanks.
My question is bullet is kinetic energy vs. imparted energy. In looking at ballistics gel it would appear the 7.62 imparts more energy into the target (unkown if 5.56 bullet was full metal jacket, soft or hollow point whereas 7.62 was Power Shok). Has anybody looked at this factor?
I've been told that some of the fast bullets have more impact at longer distances when they have slowed down, i.e. they are transfering energy into target vs. through target.
I've been shooting 139 grain 7mm at 500 yards and it seems quite effective.
Bert, it would be safe to say that the 7.62x39mm puts more energy on target due to a bigger bullet and more surface area, if you were to compare FMJs that do not expand. For home defense though, I would not recommend a FMJ. A pointed soft point on the other hand would do well in either caliber and dump much more kinetic energy on target.
I have AR's in 5.56, 223 Wylde and one in 7.62x39. I have no favorite. They are all fun and each one has been set up for different purpose.16's 20's and a24. . I am building a long range 6.5 Grendel w/24inch barrel for long range target. I think this is a excellent cartridge . I think the 6.5 would make a perfect military cartridge.
It definitely would make an excellent cartridge for the military. The problem though is logistics. I dont see the military ever switching from the 5.56 NATO anytime soon. Big reason would be the lethality of newer 5.56 offerings. The MK262 ammo is the bee's knees and offers excellent terminal ballistics against soft targets.
I actually read somewhere (not sure its true) that the military uses FMJ because although a kill is great,the real object is to wound. The idea being if a soldier or 2 is helping get a wounded man to saftey that would be 3 less people possibly putting shots on target for the time being no matter the length of time. Anybody know if any truth to this?
I have never seen a true source for this statement, I have seen it repeated though.
I do not believe it is true in any form, there are a long list of reasons why fmj may be used and only a few for HP ammo.
For many nations the use of expanding rifle ammo is a war crime, this is probably the largest reason why it is rarely used.
The Hague Convention of 1899, Declaration III, prohibited the use in international warfare of bullets that easily expand or flatten in the body. It is a common misapprehension that hollow-point ammunition is prohibited by the Geneva Conventions, however the prohibition significantly predates those conventions
Exactly right. Bouncing Betty's bounce about wast level for the same reaon... to maim, not kill...
Millitary just switch its 303 7.6254 to 6.5 for saw and snipers this year
For one of your future articles can you please do a guide on how to build an AR in a 7.62x39 caliber (I guess sometimes referred to as AR-47). Your guides have been invaluable to me. I have build a rifle and a pistol using your guides and with parts you recommend. I've also bought other gear based on your reviews and guides. Have been wanting a guide for an 7.62 AR!
7.63x39 AR is not trivial and a little more involved than just putting an upper together. There are different Mag (P-products vs ACS), different barrels, different BCG. To put one together requires a bit more tinkering, maybe using different weight buffer, maybe an adjustable gas block, The biggest challenge I've seen people disucss is which barrel to get so that the M4 feed ramp can properly feed the large 7.62x39 round. Some people suggest taking a Dremel to a barrel extension. Hope you can shine some light and recommend a barrel. Faxon is often recommended, but their 7.62 is a bit pricey. How about a $99 KAK industries value line, or maybe Spitna Precision (and numerous others, CBC, ArStoner, KAK, green mountaine, etc...)
Would love to read one of your guides!
Also, maybe you can compare some pre-built 7.62x39 uppers like the ArStoner from Midway or ones from CBC industries.
I actually built one for a friend. He ended up getting a Bear Creek Arsenal barrel in 7.62x39 and it had the oversized feed ramps on the barrel extension. He also got a Toolcraft BCG with a titanium firing pin to get a little more speed striking the firing pin. It can help for steel case ammo with a harder primer. He was running ASC mags, and he has been very happy with it. Runs like a champ doing fun range sessions.
Haven't looked at bear Creek barrels. Thank you for the suggestion
I like reloading 7.62x39, very accurate at 100 yards (1 ragged hole) in a handy rifle. Good gun for the kids. Buddy’s grandson killed his 1st deer with it. Hit it at 50 yards, went another 50 and dropped dead.
Anything is accurate at 100yds
Closer range, dense vegetation...advantage 7.62
Weight, accuracy, range...advantage 5.56
6.5 creedmoor for those of us who operate and are serious about it.
What?! No comparison to .50BMG?!! And here I thought this was an article about practical shooting applications! How am I going to make a choice to deal with my squirrel problem now?!
.50 BMG for squirrels? Are you mad? .338 Lapua Magnum is clearly the only right choice ;)
It’s not .50bmg but .50 Beowulf for the AR platform. Noob.
7.62x39 for me. Ive seen numerous tests where it will go through cinder blocks or car doors and still smash a watermelon to 300 yds. 5.56 won't. Very few enemies will stand out in the open....
Hate to tell you my friend by no 7.62x39 round its going to 300 yrds after hitting a concert block or after going through a car... its no wonder round... Still don't want to get hit by it
The right ammo in 5.56 will go through a standard vehicle’s door and will be able to neutralize the threat sitting inside assuming you hit where it matters. If you plan on shooting through a vehicle or walls and then blow a melon hiding behind it, get something meaner than either caliber.
Of those listed only M193 will punch through lvl III body armor.
The reason for that is velocity. Velocity is the enemy of armored steel.
If you're expecting to have to shoot through body armor or obstacles you'd be better of with something in 308 / 7.62x51 (like an ar10). M193 will only penetrate at fairly close range.
The main reason I choose and AR in 5.56 is accuracy and less recoil. It really depends on what you want it for. If you're shooting paper from a bench, it really doesn't matter I guess... But if we are talking combat, I will take the accuracy, less recoil, less weight and more ammo that the AR platform in 5.56 gives me. There is a big difference between shooting at paper from a bench and shooting at a moving target, that is shooting back at you while you are also moving... That's when low recoil and accuracy can decide who survives the gun fight. 2 combat tours with Aco 3/505 PIR 82nd ABN as an infantryman gives me a rather unique perspective... But you certainly don't want to get hit by either of them. to each their own as they are both great weapon systems... good write up by the way.
I just finished building an AR in 7.62x39 after shooting one earlier this year and love it. Also, I have an AR in 556 and building one for 223 Wylde chamber. I love both calibers and each have their own uses. Thanks for the info and keep up the good work Ken.
This article is totally confusing. I thought you were going to compare the 5.56 to the 7.62x39 for KE, cost etc but it looks like you ended up comparing the .223 to the 5.56?????
Take another read I think he covered the basic advantages disadvantages of both. 233 in steel casing may have thrown you of track.