AR in 5.56 or 7.62x39

Jmac604

Jmac604

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I am in the process of getting my first AR. I have shot a number of them and love the accuracy and look, etc. I have considered the VZ58 but am concerned about the availability of after market parts to "spruce it up".

Now....the big question..5.56 NATO vs 7.62x39.

My objective is to have a light, accurate, hard hitting rifle for target shooting but with enough stopping power should I need it. I constantly "chase my tail" on this issue.

Any advice or suggestions as to caliber or even the type of rifle?
 
7.62x39 is notoriously bad at functioning effectively and consistently in the AR platform. You may want to try a 300 Blackout build if you want something different ballistically speaking than 5.56/.223. Same BCG, gas system and mags as 5.56/.223 but a larger round that has performed well at range and functions well in the AR.
 
What he said. While the idea of shooting cheap surplus 7.62x39 through an AR sounds attractive at the time, consider those corrosive primer salts getting into every nook and cranny of your bolt and carrier. More importantly, consider that the case head of the 7.62x39 requires a bolt with a lot of meat shaved off of it to fit. ARs in 7.62x39 break bolts frequently.

With a .300 BLK you can not only use the same bolt but the same mags, and your bullet selection is vastly improved with equal or better performance. If you want to throw cheap 7.62X39 downrange get an SKS or an 858 instead, they'll handle it better than an AR and are nonrestricted to boot.
 
5.56 is the way to go....don't limit effective range, the 7.62 just does not cut it for me in most situations....Hey you could always get a csa in 223...
 
The great thing about an AR is how easy it is to switch calibers and builds. I say go for a .223 to start. As mentioned 300 AAC can do some excellent things, but from what I've heard it can get very expensive. Haven't checked the prices so I'm just talking from rumor here. Yeesh, quick google shows some of the first couple results costing anywhere from $130 for a case of 200 115gr Remington UMC, to over a dollar each for some other brands.

Maybe even try for a .223 Wylde chamber to really maximize your ammo potential.
 
I own both calibers, unless you spend the extra money with a piston setup I would go with .223, ex-warsaw pact surplus ammo can have inconsistent load that might not generate enough gas to cycle a DI system properly.
 
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I also own multiple guns in both. You mentioned stopping power which infers a hypothetical "situation" and not just the range. The 7.62x39mm is around 120gr. whereas the 5.56x45mm is around half that (varies, but for the NATO FMJ it's 62gr), but the 5.56 makes up for it with higher muzzle velocity (around 3000fps), so the foot-pounds of energy are almost the same, only a tad higher for the 7.62. The higher velocity though, gives the 5.56 a flatter trajectory i.e. more accuracy (unless very windy where the lower weight is a disadvantage).

The 5.56 seems to get a bad rap for its intended purpose of wounding vs killing/ penciling through tissue, etc. -- but if you study the terminal ballistics it does yaw and fragment in the wound channel, so it will definitely stop an enemy combatant.

In any case, the 5.56mm is lighter and more compact so you can carry more ammo, plus less recoil for faster, more accurate follow-up. In military terms this leads to the SALVO concept, where in low-intensity conflict more rounds downrange is more effective than fewer rounds of higher power.


All that said, it's not a big investment to get an SKS and a full crate of 7.62x39mm ammo (less than $500) as a backup to your AR -- it lets you mix it up at the range and that ammo is much fun to shoot. It will give you some reference to compare with and you'll appreciate the AR even more.
 
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From the perspective of the rifle as a weapon, if you can guarantee that you won't engage targets much beyond 200m then 7.62x39 is a decent calibre in a short barreled rifle - beyond that, or in a longer (16 inch+) barreled rifle the 5.56 is the better choice. As far as ammo costs go, the 5.56 can be reloaded for a very reasonable cost.
 
Guys, the way I read his question, it sounds like the original poster thinks AR stands for Assault Rifle. He's not actually asking about an AR15 platform rifle, just black rifles in general.

As such, all the answers to this thread are pointless and will likely just confuse the guy.
 
Armedsask said:
Guys, the way I read his question, it sounds like the original poster thinks AR stands for Assault Rifle. He's not actually asking about an AR15 platform rifle, just black rifles in general.

As such, all the answers to this thread are pointless and will likely just confuse the guy.
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No, I am actually referring to an AR platform....I just can't decide on a specific calibre IE 5.56 vs 7.62x39, etc.

All the posts have been very helpful and I appreciate it.

One more question.....can a 5.56 NATO chambered AR fire .223? The reason I ask is that I remember (hopefully correctly) reading that the casing for 5.56 has a different casing shoulder than civilian .223. Is that a concern?
 
Armedsask said:
Guys, the way I read his question, it sounds like the original poster thinks AR stands for Assault Rifle. He's not actually asking about an AR15 platform rifle, just black rifles in general.

As such, all the answers to this thread are pointless and will likely just confuse the guy.
Click to expand...

I'd agree with you from a logical standpoint and from what I know about modern history. I'd still like to hear from our veterans who have seen some MLI action before forming a definite opinion :cool:
 
If you have a 5.56 chamber you can fire .223 if you have a .223 chamber you can probably still fire 5.56. The 5.56 chamber has a longer throat, increasing the distance between the cartridge and the rifling and this reduces pressure allowing the cartridges to be loaded with more powder for higher velocity. As such if you shoot 5.56 out of 223 you lack that longer throat so the chamber pressures will be higher, which might still be okay since most civilian guns are tested to higher pressure than military guns anyways.
Things like 223 wylde were made with both in mind, and have been reported to have rather good performance. With modern metallurgy and QC you should be able to use either interchangibly, it is on older firearms or ones of questionable parentage that you run into the infamous kaboom scenario.
Or something, I might be thinking of something else. There was a gigantic thread with pictures and diagrams at one point, should be somewhere around the black rifles forum. Probably under a pile of dead bear cavalry.
 
barrett50cal said:
I also own multiple guns in both. You mentioned stopping power which infers a hypothetical "situation" and not just the range. The 7.62x39mm is around 120gr. whereas the 5.56x45mm is around half that (varies, but for the NATO FMJ it's 62gr), but the 5.56 makes up for it with higher muzzle velocity (around 3000fps), so the foot-pounds of energy are almost the same, only a tad higher for the 7.62. The higher velocity though, gives the 5.56 a flatter trajectory i.e. more accuracy (unless very windy where the lower weight is a disadvantage).

The 5.56 seems to get a bad rap for its intended purpose of wounding vs killing/ penciling through tissue, etc. -- but if you study the terminal ballistics it does yaw and fragment in the wound channel, so it will definitely stop an enemy combatant.

In any case, the 5.56mm is lighter and more compact so you can carry more ammo, plus less recoil for faster, more accurate follow-up. In military terms this leads to the SALVO concept, where in low-intensity conflict more rounds downrange is more effective than fewer rounds of higher power.


All that said, it's not a big investment to get an SKS and a full crate of 7.62x39mm ammo (less than $500) as a backup to your AR -- it lets you mix it up at the range and that ammo is much fun to shoot. It will give you some reference to compare with and you'll appreciate the AR even more.
Click to expand...

^ what he said lol
 
Now that the ammo question is answered....onwards and upwards

For reliability in an AR: Short Stroke Piston vs Direct Gas Impingement? Is one inherently better or is it something not worth worrying over?
 
Personally I like gas. The piston systems I've seen all appear proprietory. Brake a part and you got to go to that producer. Producer goes out of business or stops supplying that part then what do you do?

Gas is universal for parts, and works. If it ain't broke, don't change it.
 
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