Reloading 223 vs 5.56mm question

In my experience, if you don't load at max and go through the same processes like trimming the brass, you will probably not be able to tell the difference. One exception will be bench rest competitions, but other than that you are okay IME.

Check the load data for each and compare. I just checked two of my loading sites and neither had data for the 5.56 NATO. Everything they shown had data only for the 223 Remington.

1911-9mm said:

Check the load data for each and compare. I just checked two of my loading sites and neither had data for the 5.56 NATO. Everything they shown had data only for the 223 Remington.

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But what if all you have is 5.56 brass

crosswater said:

But what if all you have is 5.56 brass

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5.56 military brass may have a thicker web at the case base which could raise pressures. It's also usually softer. Just don't use max loads. Are you chambered for .223 or 5.56?

crosswater said:

But what if all you have is 5.56 brass

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The brass is the same dimensions, (although wall thickness may be more on 5.56).
5.56 is hotter than .223, so you can load and shoot .223 in 5.56 brass, and guns chambered for 5.56.
The opposite is not true. Don't want to load full 5.56 loads in a .223 rifle!

I was always told don't load to 223 specs in 5.56 brass and don't load to 5.56 specs in 223 brass

mercman1972 said:

5.56 military brass may have a thicker web at the case base which could raise pressures. It's also usually softer. Just don't use max loads. Are you chambered for .223 or 5.56?

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The gun can shoot both

I thought 5.56 vs 223 was always centered around the cartridge case and any data labled "223 Remington" was only for use in 223 cases

CFE-223 take my 60 grain Vmax bullets out to 3000 fps.
That's not quite max load, and it shoots to about 1 inch at 100 yards.
Works in both 223 and 556 brass.
That's plenty good for me.

crosswater said:

The gun can shoot both

I thought 5.56 vs 223 was always centered around the cartridge case and any data labled "223 Remington" was only for use in 223 cases

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Yeah, it's the barrel/CHAMBER issues - unless the weapon is marked as 5.56, do NOT run 5.56 NATO loads in your 223. NATO uploads (like 9mm parabellum) their cartridges, cuz - you know - civilians are wussies.

Your ruger american Ranch is fine with the differences and won't care ;-)

So it doesn't matter what cartridge case I use?

Both can be loaded to 5.56 velocities?

My Hornady book has loads for .223 and Service loads, The 5.56/Service loads start at 60g bullets thru 77g. All of my rifles are 5.56 and I use the load data for the weight bullet I am using. 55g and lighter use .223 and 5.56 for 60 plus weights

Most of my brass is .223 and I use 62g and 68g bullets so I use Service Rifle data to load them. Mostly with CFE223 powder. I do not load to max.

So what is the difference between 55 grain FMJ 223 and 5.56 factory loads?




5.56mm

Ramshot reloading charts show listing for 5.56 Nato loads data.

For me, I would only use 5.56 data in 5.56 brass as it is hotter. Your bolt rifle will take higher pressure than a gas AR 15

Like longarm said above, the brass can be used in either; what velocities you get with either will depend on your gun. The 5.56 chamber is a little different in the leade, so you can use .223 specs in your 5.56 chambered barrels without issue, BUT, the 5.56 specs ammo is loaded a little bit longer as far as OAL, so don't shoot 5.56 ammo in your .223 chambered guns. If you are using 5.56 brass in a .223 chambered gun, work up loads for .223 specs and be sure your bullets are not touching the rifling when chambered. The thicker web on the 5.56 brass will require you to work up you load data because of the reduced internal volume in the case, but you should be able to use the brass as long as you do that.

I wish more reloading manuals would split out 223 vs 5.56 spec data

Actually there isn't any difference in the internal volume of the 5.56 and. 223 case.

Some military 5.56 brass is lighter giving it more internal capacity for powder and some is thicker.

On the outside, the brass is identical.

The chambers are a touch different. A 5.56 chamber has a larger/longer throat allow pressure to drop before the bullet engages the rifling.

I shot many thousands of rounds of 5.56 ammo in a 223 barrel before the internet said it was bad.