223 vs 5.56

[Mike1234567]

I won't buy a firearm that isn't "guaranteed" to reliably chamber and cycle both. The Saiga .223/5.56 is my choice because I'm not looking for "ultimate accuracy" (in semi-auto) but rather "ultimate reliability". Also, I want versatility whenever it's available.

 

[rust collector]

If your top priority is reliable function, you will specify a 5.56 chamber. It will work with any 223 or 5.56 round that is manufactured to SAAMI or NATO spec. If reliability is shared with accuracy as a priority, the Wylde chamber seems to be a good compromise.

If you are a varmint hunter, competitive target shooter or accuracy is the top consideration, you will want a tighter chamber that does not meet 5.56 specs, but removes some of the "wiggle room" that helps when gun or ammo is dirty, but hurts when you are looking for tight groups.

Does observation that the gun didn't kaboom when the mil spec ammo was fired in a chamber marked 223 mean that it is safe to do? I don't believe it is. Damage from overpressure is cumulative. We don't necessarily know or hear about it until there is catastrophic failure. I have seen nothing to make me want to walk on the wild side of this long-playing disagreement.

 

[bigedp51]

When the .223 and the M16 first came out they "BOTH" had the same 1 in 12 twist, with the advent of longer and heavier bullets to "improve" the M16 round the twist rate was changed in the M16 to a 1 in 7 twist. To accomplish this the throat was lengthened on the M16 to accommodate the longer bullets.

When the throating became different between the 1 in 12 twist .223 and the 1 in 7 M16 rifle is when the "change" took place and higher pressure spikes could happen in commercial .223 rifles with the shorter throat.

There is "NO" difference in chamber pressures between the .223 and the 5.56 NATO round. The confusion comes from NATO EPVAT pressure testing methods where the pressure is measured at the neck of the case verses mid case for SAAMI pressure testing.

My Stevens 200 .223 has a 1 in 9 twist and is long throated and can safely fire both commercial and military ammunition.

Both the SAAMI and the European CIP conceder the .223 and 5.56 NATO to be the same cartridge, with the exception of twist rates and the corresponding throating differences.








The civilian and military 30-06 are for all practical differences were the same, the .308 and 7.62 were the same and the .223 and 5.56 are the same. The only differences happened when the military changed the twist and bullet weight for the M16 rifle which effected the older commercial .223 with the 1 in 12 twist and the corresponding SAAMI warning about ammo interchangeability.

Below, two five gallon buckets of .223/5.56 cartridge cases in my basement segregated by make and type. If you would do a little research yourselves instead of relying on rumors and myths you would already know what you have just been told.

 

[rust collector]

I guess it depends on who we believe

because we don't have strain gages to do our own pressure testing.

I enjoyed this statement from Armalite. I found an earlier version, and more recent one. They explain that many rounds of NATO ammunition have gone up the pipe from SAAMI spec chambers safely. They go on to explain that they use a Wylde chamber on their stainless barrels. Why would they do that if there was no issue? http://www.armalite.com/images/Tech%20Notes%5CTECH%20NOTE%2074%20%205.56%20vs%20223%20vs%20Wylde%20090817%20Rev%200.pdf

Most of us enjoy loading what works best in our rifles. No use getting knickers knotted.

 

[alsaqr]

The only reason the 5.56 NATO chamber is different is to accommodate dirty ammo

Exactly.
The longer throat of the M16 rifle is there because the weapon is gas operated and there is no camming action to assist in chambering a dirty round. Additionally, the gun must be able to chamber and fire ammo made by all NATO countries.

BTW: The 7.62mm NATO chamber has a longer throat than the .308.

 

[jackpinesavages]

5.56 NATO is better; Less Filling.

 

[wally]

We don't necessarily know or hear about it until there is catastrophic failure.

If there has been one from shooting 5.55 in a .223, I'd like to hear about it!

www.thegunzone.com collects all sorts of KaBoom stories and pictures but doesn't seem to have any from using 5.56 in a .223 or using .308 in a 7.62.

 

[303tom]

Exactly.
The longer throat of the M16 rifle is there because the weapon is gas operated and there is no camming action to assist in chambering a dirty round. Additionally, the gun must be able to chamber and fire ammo made by all NATO countries.

BTW: The 7.62mm NATO chamber has a longer throat than the .308.

For exactly the same reason.

 

[borrowedtime69]

My head hurts....

talked to my trusted gunsmith who said that its no problem to fire 5.56X45 out of a .223 remmy, as the chamber of my Remington 700 is one of the best made and will eat 5.56 all day long with no problems.

Call the factory, they say NO WAY! i realize they are probably trying to prevent some lawsuit, so dont know how trustworthy that is.

Have experianced gentlemen here and on other message boards saying they have shot 5.56 in their guns, no problem. also have gentlemen in the know here and else-where say that its a total no-no....

:banghead:

Is there somewhere i can get the FINAL answer??? do i actually NEED to get my barrel drilled to be a Wylde chamber??? will accuracy suffer if i do?

Im just looking at having a good varmint hunter and being able to use cheaper 5.56 surplus ammo in SHTF situations.

 

[JHenry]

I think 5.56s shoot both but .223's arnt necesarily built to withstand some of the hotter 5.56 loads. they can function with 5.56s but im sure if it wasnt built to handle it your rifle would wear down pretty fast

EDIT: although those guys up there sound like they know alot more than me

 

[dogrunner]

Bigedp51: I believe if you'll check a bit more closely you'll find that the very first twist rates for the Armalites was 1/14.............that was changed in the very early 60's when it was determined that the barely stable projectile tumbled in extremely cold conditions. Downside was that the induced 'yaw' from that slow twist was a real factor in the effectiveness of the round.

My reading states that Stoner deliberately incorporated that nearly unstable twist to improve the lethality of the round.

As an aside, I was stationed at the Army's Arctic test center during that period and I well recall the comments as to the effect of exteme cold on the performance of the round. Temp's as low as 70 below were not uncommon.

You'd be amazed at just how little works at those extremes!!!

 

[brnmuenchow]

I think it really depends on the rifle, if it is chambered for .223 and you fire 5.56 and it does not like it, but your buddy next to you has a different brand rifle and also chambered for .223 and loves it than stick with what your's likes. It's not like I hear, "Man/Women blew face off for using 5.56 NATO in a .223 Rem. rifle" everyday. I think most manufacture's are taking the loads in consideration when building the components for the rifles, even if they do still print ".223 Rem." on the rifle.

 

[beatledog7]

The difference in 5.56 and .223 is how the case is loaded (primer, powder, bullet), and this is driven by its intended use.

Ever try to buy a set of 5.56 reloading dies? You can't. Once fired, 5.56 brass is .223 brass. It's all the same until you load it again.

 

[WinThePennant]

OKAY - In a nutshell, if you are building an AR15 then what? Build for a .556 because it handles higher pressures and can also shoot .223?

 

[beatledog7]

Whether you subscribe to the higher pressure school or the longer throat school, or both, it still makes sense to build an AR-15 as a 5.56. That way if you buy ready-to-shoot ammo you can use either one without risk.

If that's wrong, somebody chime in.

 

[rcmodel]

I agree.

Unless you are building a very specilized varmint rifle, there is no reason for a .223 chamber.

It might give a little accuracy edge with lighter varmint bullets.
But it might not too.

rc

 

[TonyAngel]

The big difference between 5.56 and .223 is the pressure generated by the loads. In .223 form under SAAMI specs, the load it rated up to something around 50K CUP. In 5.56 form, the load is rated to a NATO spec of up to 60K CUP; so, put simply, 5.56 is just loaded hotter.

The difference between the rifles that shoot each respective round is in the chamber specs. .223 has a tighter chamber spec, which (according to spec) is supposed to have a slightly shorter headspace and shorter throat. 5.56 has a more loose chamber spec as compared to that of the .223, with a slightly longer headspace and longer throat.

If you try to shoot 5.56 out of a .223 that has a tight chamber, you could encounter something as simple as a sticky bolt or worse.

I've seen lots of guys shoot 5.56 out of their .223 bolt guns and ARs; but then, ARs tend to have chamber specs on the sloppier side to aid in function and reliability. The bolt guns, especially Remingtons have less than match grade chambers so that they can accommodate a wide range of ammunition coming from various manufacturers. Remingtons are so sloppy that fired brass from many Remingtons won't even come close to chambering in another brand of rifle and the throats are so long that you usually have to load the ammo almost too long to fit in the magazine just to get to the lands.

In .223s that have sloppy chambers and/or long throats, shooting 5.56 may not have any adverse affects, but doing so in a rifle with a tight chamber could mean trouble.

 

[TonyAngel]

If you're building an AR, go with a 5.56. I've used a few of the barrels from Bravo Company with the 5.56 "match" chamber (who ever heard of such a thing?). When I first read the claim, I kind of laughed, but the barrels do shoot and very well.

 

[bigedp51]

The big difference between 5.56 and .223 is the pressure generated by the loads. In .223 form under SAAMI specs, the load it rated up to something around 50K CUP. In 5.56 form, the load is rated to a NATO spec of up to 60K CUP; so, put simply, 5.56 is just loaded hotter.

You are mixing 50,000 CUP (copper units pressure) with 60,000 psi transducer method. The pressure differences are insignificant and the "ONLY" differences are twist rate and throating for the .223/5.56.

The same confusion exists with the .308 and 7.62 NATO, DO NOT mix cup with the psi trandsducer method.

Below you can see if you put 32 psi in your tires everything will be OK, BUT if you put 220 kPa in your tires they will blow up and kill everyone in a 300 yard radious.

 

[TonyAngel]

I'm not getting PSI and CUP confused. 5.56 is a hotter round that .223.

 

[Tadracket]

....Im just looking at having a good varmint hunter and being able to use cheaper 5.56 surplus ammo in SHTF situations.

Ammoengine lists this round from Tulammo as the cheapest going right now at 20 cents a round. I would shoot this in any .223 and not worry about it.

 

[bigedp51]

TonyAngel

Anyone with two fingers and a computer can write anything they want to on the internet. The European CIP the Counterpart to the American SAAMI lists the .308/7.62 NATO and the .223/5.56 NATO as the "SAME" cartridge and pressures.

NATO EPVAT pressure testing methods measure the chamber pressure at the neck of the cartridge and the SAAMI standards are taken at mid case. The NATO EPVAT pressures will read higher for the exact same pressure measured at the mid point of the case on commercial .223 cases.

The new 5.56 loadings use "longer" and "heavier" bullets and the throat was lengthened and the twist changed on the newer M16 rifles. Commercial rifles with the longer throat can shoot military ammunition without any problems.

This is why the wylde chamber throat is considered a compromise and why you can shoot both military and commercial cartridges safely in ANY rifle with this throating. If you fire a "longer and heavier" military bullet in a short throated .223 rifle with a 1 in 14 twist rifle you are going to have a pressure spikes because it was not designed to shoot these larger bullets.

 

[borrowedtime69]

further question

bigedp51 said :The new 5.56 loadings use "longer" and "heavier" bullets and the throat was lengthened and the twist changed on the newer M16 rifles. Commercial rifles with the longer throat can shoot military ammunition without any problems.

This is why the wylde chamber throat is considered a compromise and why you can shoot both military and commercial cartridges safely in ANY rifle with this throating. If you fire a "longer and heavier" military bullet in a short throated .223 rifle with a 1 in 14 twist rifle you are going to have a pressure spikes because it was not designed to shoot these larger bullets.

So, if i stick to shooting the smaller/lighter 55 grn mil-spec stuff, i'll be ok then? thanks!