Can you load .223 cases to 5.56 specs?

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BullHeadedGideon

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Hello guys & gals,

From what I understand, the thickness of the cases is what makes the pressure difference between .223 & 5.56.

So my question is, excuse my ignorance, say I bought some .223, shot those rounds, then loaded to "5.56 specs"... Would that be a bad idea? Would that be too much pressure for the thinner cases or something?

What about the other way around? Say I bought some m855, shot those rounds, then wanted to load to ".223 specs." Would that create too weak of a cartridge or something?

Thanks in advance for the responses,

Bull.
 
The case is the soft seal. And the hardness of the head will determine how long the cases last. You may loose primer pockets faster at higher pressure and all brass is not created equal. I have no issue loading either to full pressure.
 
Some military brass is thinner, and some thicker, when you are talking .223/5.56, not like .308 where the military brass is consistently thicker/heavier.

If you search there are some very good explanations of the small differences in .223 & 5.56 out there.

The cases can take it safely, although, as posted, higher pressures are harder on cases, especially softer brass alloys. You can load your gi spec or .223 spec brass either way, but be careful loading to "5.56 specs", since you are looking at higher pressures, and your cases may or mat not have less capacity than the ones used for the load data.

Be careful out there. :)
 
I reload .223 and 5.56 (to NATO pressure/velocity).

My .223 is loaded using mixed brass for my 3gun and practice stuff, precision/hunting ammo all gets either REM or WIN that's gone through prep.

My 5.56 loads all go into .mil Lake City brass. For these loads brass longevity isn't a concern, I don't shoot all that many of them and LC is everywhere. What is a concern is easily identifying my 5.56 loads and doing load development using the same make of brass. As the other's pointed out, both 5.56 and .223 stamped brass does vary in thickness.
 
BullHeadedGideon said:
From what I understand, the thickness of the cases is what makes the pressure difference between .223 & 5.56.
Click to expand...

Some commercial cases are thicker than military cases and vice versa.

Been reloading .223/5.56mm since 1968. The vast majority of my .223 reloads are fired in bolt action rifles. i've tried all the brass available including Lapua. Unless you're a serious bench rest shooter save your money and use once fired LC brass. LC brass is good for at least five moderate reloads.

Having a ton or two of military M193 ammo i make my own once fired brass. Cases are prepped in batches of 100-500, reloaded about three times and dumped into the brass barrel. i don't normally load bullets heavier than 55 grain; IMR 3031 powder works well for me.

In an accuracy test i loaded 40 rounds into fully prepped mixed brass and compared the groups against 40 rounds loaded into LC 13 brass. Firing five shot groups at 125 yards, the mixed brass reloads made groups that averaged .2 inches larger than the LC 13 brass.
 
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If you look at the manuals with both 223 and service rifle 223/5.56 and you compare there data when using same bullet and powder . There realy isn’t much of a difference. Sometimes the AR max charge is higher and other times the 223Rem max charge is higher .

It’s been said that they are actually pretty much the same . The difference is how they test the pressure for each cartridge 223 vs 5.56 .
 
BullHeadedGideon said:
What would you say are some good brands to buy in regards to brass-longevity?
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Generally for me winchester is the best, Remington is the worst.
I never tested 223 because I figured out early on I would lose the brass before I could reload them enough times to fail.
It wasn't even worth annealing the case necks because I lose them before I load them enough times for annealing to make a difference.
For bolt action, lever gun and revolver winchester for longest lasting.
For Semi autos buy whats made of brass and cheap.

It looks like the brass and projectile for 223 amd 5.56 are the same but the gun is different, free bore and throat are cut different. 5.56 has a longer free bore by a lot. So Ammo is the same, tested different and the chamber for each gun is cut a little different as far as I can tell.
 
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I wouldn't mix brass in .223 or 5.56. I'm not sure what "tests" on mixed brass could possibly tell you. You've introduced a variable that you simply can't account for.

I sort by headstamp; I segregate .223 brass from AR 5.56 brass.

I've never had a reason to load beyond .223 loads.

I'm a firm believer in manuals, when I started with a .223 bolt gun, I chose the bullet I wanted to use, bought the manual, and bought the components listed in the recipes. That way I can take advantage of all the testing with all that high priced gear the company did before they printed the manual. I did the same thing when I started loading for my AR, and I've never found a reason to change the method.
 
Toprudder said:
That has been my observation as well, for 223/556 brass.
Click to expand...

.308/7.62mm brass is a known quantity, in most 'cases,' with a few exceptions. I've found that to not be the case with .223/5.56mm... it's all over the map. I tend to stick with one or two headstamps, and even segregate those... i.e: LC13 vs LC11, etc. because I HAVE seen variances between date codes. I'm not a big range brass scrounger, at least with rifle brass, so I'm using my own virgin brass or brass from factory fired by me.

As far as loading to '5.56mm' levels... if velocity is your absolute goal, well, then, OK. I've found that I get better accuracy with more moderate loads... that is, Service Rifle data loads that are in reality down near .223 levels. The paper doesn't know the difference, and likely any other thing that might be the recipient of a bullet wouldn't miss that extra 200fps or whatever. JMHO. All my AR barrels are 5.56mm chambers, so I could reasonably load to the higher levels, but there are too many variables within my handloads... bullets and brass among them... that I have discounted the desire to do so. I have sheared bolt lugs off an AR, so I also might have a different frame of reference.
 
I'm not sure if it was a thicker wall, or just a thicker base, but when I was comparing brass by weight, Winchester White box was heavier than Lake City.

I settled on Lake City for my hand loads.
 
I would worry much less about matching Q3131 or XM193 or whatever velocity and worry more about how the load performs in consistency and accuracy.

As far as sorting .223/5.56 brass - I rarely do it. I keep a bunch of Speer nickel cases in the mix for accuracy loads - they're easy to identify. But for general range ammo.....it's mostly LC brass, but all sorts of other commercial .223 in that mix. For just plain old FMJ range loads there isn't a good reason to sort - unless maybe you don't want to deal with crimped brass or something.

I wouldn't worry about longevity much either. .223 brass is everywhere, esp LC. I'm pretty good about recovering my brass & generally get 90% picked up, bush hog gets the remainder. I have 1x and probably 7x+ fired in the mix. It either passes inspection or it doesn't and in the end it seems there is equal chance you will step on or fail to recover a 1x fired piece as a case mouth with split on a 6x fired piece.

Making hunting loads, something for a match, something for precision shooting, sure, be much more detail oriented. If you're filling 50cal cans for general training ammo, sorting brass is just extra processing for the sake of extra processing (IMO).
 
The easiest way to think about 223 vs 5.56 is to reference Western Powders' data because they have data for both.

https://blog.westernpowders.com/wp-content/uploads/2019/04/WPHandloading-Guide-7.0-Web-REV.pdf

After you investigate, what you should notice is that their 223 data has some overlap with the 5.56 data. In most cases, a maximum 223 load will be above the minimum 5.56 load. Additionally, Western used Winchester cases and WSR primers in their test barrel. I would personally use a different primer for use in an AR-15, but that is the reloader's choice.

However, the more important thing to ask is: Does the governmental standard for ammo meet the needs of a handloader or are the needs different? Most handloaders will prefer accuracy over a specific bullet weight at a specific velocity.
 
Your reloads have no idea to which page you opened your manual. Start low, work up, and watch for signs, stop when you see them. Thin brass might allow a bit more powder without creating pressure issues present with the same load in thicker brass. Your chamber will not perfectly match that which was used to develop the manual data, your brass won’t either, your freebore likely will not be the same, so even when loading to the same COAL, the odds of actually achieving the same pressure as the test barrel is exceptionally unlikely, so pretending reloading manuals mean anything much more than an approximate waypoint on a seafaring journey is naive.

Start low, work up. Stop and back off back into “safety” when your rifle or brass tell you it hurts.
 
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