Can "military" rifles in .223 shoot 5.56?

[dakota.potts]

Saving up for a rifle I'm doing a lot of research on the options that are available out there that aren't an AR-15, just to see what's on the market that nobody ever talks about.

Two rifles that really interest me are the Steyr AUG (especially the A3 model) and the HK53. Both of these say that they are chambered for .223.

I find it odd that two military rifles, one of which is in active service in many countries, can't use a 5.56 NATO round. Can they only use this round? Is it something about the chamber or the pressures involved?

Also, a tangential question: Is there any difference in performance between the two rounds out of the same gun? Does one drop faster? Will you have to do a significant re-zero if you change from 5.56 to .223?

EDIT: Perhaps I have received some bad information. The more I look into this, I find that both of the rifles in question are chambered in 5.56. It's possible that people have been referring to it as .223 as shorthand, causing the confusion.

 

[Mike38]

I can’t speak for the Steyr AUG or the HK53, but can tell you this. The Saiga .223 (AK47 pattern rifle) is chambered for the 5.56. It’s stamped .223 for import reasons, that help make it a “sporting rifle”. Maybe this is what companies like Steyr is doing? The only way to find out for sure is contact the manufacturer.

 

[Willie Lowman]

I have a friend that is a SOT. He has a HK53. We have shot more 5.56mm ammo thorough that little gun than you can shake a empty mag at.

I don't know why they are marked .223 but they have 5.56 chambers.


This is the only pic I have of the his 53. I took it in the garage before we went shooting one afternoon. Don't ask me what that red-dot sight is. All I can tell you is that it is/was junk.

 

[Wyosmith]

You know, this is a topic that many "real experts" in cyber space seem to know a lot about. I have been a gunsmith now for well over 40 years, and I can't say I know of any time it was unsafe..... but I sure read about it a lot.

I have read so many times on line that I have lost count, that any rifle chambered for "223 Remington" is "unsafe to fire with 5.56 NATO ammo."

All these warning seem to have come into being since the advent of the internet.
Back in the 60s and 70s about every ammo maker said right in their catalogs that the rounds were interchangable. Remington, Winchester and Federal all put it in print for many years.

I have been firing military ammo in 223s, bolt actions and autos, as well as one BLR lever gun and several single shot rifles (Ruger and TCs, Encores and Contenders) and have done so since the 60s.

I have never had a problem, and never seen a problem.
I have never actually known anyone that ever had a problem doing it either.

I only read about these dangerous rifles and ammo on line.

Chime in everyone.

Have any of you actually had a problem with this?

 

[dakota.potts]

Wyosmith, I have had one problem with Remington 700 SPS. Shooting PMC 7.62X51mm ammo, the spent casings would not extract without a ton of brute force. Turns out it was chambered for .308 and the 7.62 ammo, with thicker case walls, expanded more and got stuck in the chamber.

 

[SVTCobra306]

Consult your owners manuals, if you can get them. My Ruger Mini-14 says .223 on the receiver, but the manual calls it .223 (5.56) and states that military ammo can be used, except in the current target model that is chambered .223 only.

I have fed it both, haven't had issues except with some bad gun show reloads a long time ago.

 

[Lucas McCain]

7.62 ammo expanded more because the pressures were higher. Because the military brass has thicker walls that don't cause it to expand more. What caused high pressure? Probably a long military bullet (armor piercing) seated long and contacting the riflings. I have used military ball in my 308 with no problems. The case capacity of the military brass is less than commercial 308. I you handload military brass with a fast burning powder you may well experience high pressures.
If one is going to shoot a lot of this military, foreign ammo I would suggest that you invest in a bullet comparator, and know exactly how long your chamber throat is.

 

[Bart B.]

Lucas, .308 Win. and 7.62 NATO ammo have virtual equal pressures if measured with the same system.

http://thefiringline.com/forums/attachment.php?attachmentid=39835&d=1229900860

 

[Slopemeno]

Willie- that's an Armson OEG sight. Not bad for close work, but certainly "old-school". They suffer from some zero issues due to the design, but I've used them on paintball guns with some success.

 

[jehu]

I was taught, rightly or wrongly, and always stuck to the rule that it was OK to shoot 223 or 5.56 from the military type rifles but don't shoot 5.56 in your fine bolt action rifles chambered for 223 due to a slightly longer OAL of the 5.56 which in a tight chamber could set the bullit back in the caseing causing pressure problems. I never had a problem because I never wanted to shoot 5.56 out of my Varmint 223's anyway.

 

[kraigwy]

If you're concerned about 223 in a 5.56 or 5.56 in a 223, OR a 308 in 7.62 or 7.62 in a 308, simply get rid of the internet.

The problem never existed until the internet came out.

 

[oldgunsmith]

The difference isn't in the chamber itself, it's the throat. 5.56 military chambers were throated a little deeper and some bullets made for them could contact the rifling in a commercial .223 chamber that was throated a little shorter for commercial bullets. If in doubt, chamber a clean, shiny round and close the bolt. Remove it and look closely for rifling marks on the bullet. If you see any marks that look like they're from the rifling, you may be flirting with some high pressure problems. If not, you should have no such problems.

 

[4runnerman]

I have said this before and I will say it again. I shoot in the summer some times with 4 Guard people that shoot on the Comp team. All of them have been shooting Military loads out of their own 223 rifles for many many years.Thousands of rounds,never a issue. I agree with many here- The problem is the internet.

 

[Dc777]

People can blame things on the Internet like they are openly doing here if they want. Personally my ar is chambered for 556 and .223. Visually they look the same but I'm not going to take chances on something when it comes to a firearm. Gas and diesel both come from the same source and when poured on a pile of wood they will both do the same thing when a match is thrown on the pile, but I wouldn't ever think of putting diesel in my f-150 or gas in my f-250. Read your owners manual. " before the Internet people didn't talk about this "..., that may be true, but then again something might have gone wrong and that guy is too dumb to know how to get on the Internet and speak of his experience. Safety first when it comes to firearms. It's not worth. The risk even if the risk is small.

 

[WardenWolf]

I know the Saiga .223 and any converted versions can handle 5.56. The barrel is an underbored 7.62x39 barrel so it's very heavy and the chamber is extremely thick.

 

[BWM]

Any 5.56 NATO is good for 223 the 5.56 has a larger throat be caws the ammo that is listed as 5.56x45 is a hot load. If shooting 5.56x45 in a 223 marked barrel will raise the pressure in the gun. Some people shoots it in there gun any way.

 

[TMD]

Was never an issue to shoot either caliber out of either chamber before the internet was around.

 

[Art Eatman]

BWM, you don't have it quite right. It is said by those who advise against shooting 5.56 in a .223 chamber that the leade is shorter in the .223. If a 5.56 cartridge has a bullet which touches the rifling, the pressure could be raised. But it's not due to the "hot load", and it's not a "larger" throat.

 

[James K]

I find it interesting that warnings are issued about a short leade that "could raise pressures" or "could cause a rifle to blow up." I have to seriously doubt those scare warnings.

For many years and in many, many calibers, it was advised to seat bullets out to engage the rifling for best accuracy. Now we are told that our rifles blew up all over the place and we didn't notice. The only problem I knew of was that sometimes a bullet that engaged the rifling would be pulled out of the case when the bolt was opened without firing; the result was an action full of powder and a bullet that had to be tapped out from the muzzle with a cleaning rod.

I have done a bit of studying of bullet performance under pressure. A bullet is not a hard piece of steel being jammed into a solid piece of metal. It is (usually) copper and lead and behaves under pressure a bit like silly putty. Even moderate pressure will force it to conform to the rifling leade and the rifling itself (or just about anything else) with no significant increase in pressure. Experiments with such things as firing .30 bullets in a .25 barrel show no great pressure rise, just a long bullet.

Now I definitely discourage any such extreme testing except under controlled conditions, but the idea that a short leade will somehow increase pressures to the "blow up" point just doesn't seem to hold water.

Now what will increase pressure, is a chamber neck that is too small (or conversely, a case neck that is too thick). When that happens, often due to reforming a case to another caliber, the neck cannot expand enough to free the bullet and pressure rise is the result.

Jim

 

[JohnKSa]

There are two reasons that this subject confuses a lot of people.

1. Many .223 marked guns are set up to accommodate 5.56.
2. The mismatch is not a huge mismatch and that means it is very unlikely to cause a truly catastrophic incident. It does increase the chances of encountering blown/pierced primers and other fairly minor problems.

The combination of those two factors mean that there is plenty of anecdotal evidence that shooting 5.56 in .223 guns is a non-issue.

Here's a thread with fairly thorough treatment of the topic in question. I got interested in it awhile back, compiled some applicable information and included it in a post on the thread in the link. It includes citations from gun writers, firearms experts, ammunition companies, and firearms companies, as well as anecdotes from people who experienced the precise problems predicted by the various citations.

http://thefiringline.com/forums/showthread.php?t=530912

Don't ask me what that red-dot sight is.

It's an Armson OEG, or a variant/knockoff of the Armson OEG. The Armson OEG was first introduced in the early 1980s, and at the time it was pretty revolutionary.