Reloading .223 Cal vs. 5.56mm

[legion]

First off, my AR-15 is chambered for 5.56mm NATO, so shooting either 5.56mm or .223 Rem is not an issue for the rifle.

I bought some used brass at the gun show yesterday. It was all supposed to be all Remington brand .223, but once I opened the packs, I found them to be a mix of brands with some .223 and some 5.56. I did check the packs at the show, but they were vacuum-sealed and seemed to be all the same brand/caliber there.

My question, is, can I reload the 5.56 brass with my .223 dies. It's my understanding that the only difference between 5.56 and .223 is that 5.56 has a longer neck. I was thinking that if I trimmed all of the 5.56 cases to .223 standards, then I would eliminated the difference and be able to reload the cases with .223 dies.

Thoughts?

[m21sniper]

5.56x45mm NATO is .223 Remington.

They are the same cartridge. Do not fret.

[legion]

http://www.winchester.com/lawenforcement/news/newsview.aspx?storyid=11

Paul Nowak
5/4/2001
.223 Rem VS 5.56mm

There are a lot of questions about these two cartridges. Many people think they are identical - merely different designations for commercial and military. The truth is that, although somewhat similar, they are not the same and you should know the differences before buying either cartridge.

* The cartridge casings for both calibers have basically the same length and exterior dimensions.
* The 5.56 round, loaded to Military Specification, typically has higher velocity and chamber pressure than the .223 Rem.
* The 5.56 cartridge case may have thicker walls, and a thicker head, for extra strength. This better contains the higher chamber pressure. However, a thicker case reduces powder capacity, which is of concern to the reloader.
* The 5.56mm and .223 Rem chambers are nearly identical. The difference is in the "Leade". Leade is defined as the portion of the barrel directly in front of the chamber where the rifling has been conically removed to allow room for the seated bullet. It is also more commonly known as the throat. Leade in a .223 Rem chamber is usually .085". In a 5.56mm chamber the leade is typically .162", or almost twice as much as in the 223 Rem chamber.
* You can fire .223 Rem cartridges in 5.56mm chambers with this longer leade, but you will generally have a slight loss in accuracy and velocity over firing the .223 round in the chamber with the shorter leade it was designed for.
* Problems may occur when firing the higher-pressure 5.56mm cartridge in a .223 chamber with its much shorter leade. It is generally known that shortening the leade can dramatically increase chamber pressure. In some cases, this higher pressure could result in primer pocket gas leaks, blown cartridge case heads and gun functioning issues.
* The 5.56mm military cartridge fired in a .223 Rem chamber is considered by SAAMI (Small Arm and Ammunition Manufacturers Institute) to be an unsafe ammunition combination.



Before buying either of these two types of ammunition, always check your gun to find what caliber it is chambered for, then buy the appropriate ammunition. Most 5.56mm rounds made have full metal jacket bullets. Performance bullets - soft points, hollow points, Ballistic Silvertips, etc. - are loaded in .223 Rem cartridges. Firing a .223 Rem cartridge in a 5.56mm-chambered gun is safe and merely gives you slightly reduced velocity and accuracy. However we do not recommend, nor does SAAMI recommend, firing a 5.56mm cartridge in a gun chambered for the .223 Rem as the shorter leade can cause pressure-related problems.

[m21sniper]

Shrug, the cartridges are interchangeable. I've fired a gajillion rounds of .223 and 5.56 in the same rifles over the years.

[Jeff Higgins]

The only differences a handloader will have to consider are the reduced case capacity of the 5.56 NATO, and its crimped in primers. If you have a way to get those crimped in primers out, then ream the primer pockets, that issue is solved. The reduced case capacity is addressed simply by reducing the powder charge. Start about 10% lower than the charge you use in commercial brass. As a side note, you should do this (reduce the charge and work back up) any time you start with a new lot of brass, military or commercial. Capacities vary somewhat even in commercial brass, from lot to lot and brand to brand.

[m21sniper]

So you can get a good deal more Mv out of commercial cartridges? Hmmm, they always seem to be rated about the same on the box. They probably just load it all to military specs i guess.

Ya learn something every day.

[nostatic]

on a semi-related note: anyone ever shot PMC Bronze Line .223?

[John Rogers]

I did not see any mention of what dies you use so I would recommend a full length sizer for everything. This is especially good if you buy unknown brass at a show or from a dealer or range pick up as you never know what might have happened to the cases. I have mine set to 223 specs and every now and then one will be tight when decapping but they all feed perfect.

[on2wheels52]

I wouldn't pay as much for military brass as commercial. As noted the primers are harder to remove (keep spare de-cap pins handy) and the primer pocket has to be reamed out or swaged. And don't try to set any velocity records with the GI.
Are you finding other reloading components available?
Jim

[azasadny]

You may need to swage the primer pocket on the military (.5.56) ammo. I bought a Dillon Super Swage 600 for $90 and I've processed about 500 rounds through it to prep them for repriming. I shoot 5.56 and .223 through my Colt AR15 Sporter II with no trouble. Lightly crimp the cases and good case lube when resizing to prevent stuck cases. If you have any questions just PM me and I'll help.

[legion]

I'm using Lee dies that I have set to .223 specs. I have a neck sizer, a full-length case sizer, a bullet seater, and a crimp die. (And a powder die too, but that doesn't really count.) If I do reload the 5.56, I'll probably do it on the single-stage press so that I can pay closer attention.

I have two sets of .223 dies which came in handy when I was setting up the progressive press--I could instantly correct mistakes.

[Jeff Higgins]

You guys need to understand that external dimensions of the 5.56 NATO and .223 Remington cases are identical. The only difference (other than the crimped in primers) is in the thickness of the brass, with the NATO stuff being thicker. Since that added thickness is not added to the outside, it has to be on the inside, thereby reducing capacity.

The added capacity of the .223 does not afford it increased velocity over the 5.56. All it means is that it takes more powder in that larger case to reach the same velocities as the smaller case. Reloading data is typically developed in, and written for, commercial .223 brass. Using that data in military 5.56 brass will result in dangerous pressures unless the charges are reduced to compensate for the reduced capacity. As far as the hobby hand loader is concerned, velocities with the two cases should be identical - it just takes less powder to achieve the same velocity with the smaller capacity 5.56 brass.

There is no such thing as setting dies to ".223 specs". Like I said, .223 and 5.56 brass is externally identical. The only possible difference is in bullet seating depth, which we will typically tailor to the specific chamber in the specific gun for which we are loading. The brass makes no difference; it's the rifle's chamber that determines this dimension. In other words, for a given bullet in a given rifle, we will use the same seating depth regardless of which brass we are using.

For you semi-auto fans, sometimes chamber length will not be the determining factor in cartridge overall length. That damn magazine will be what limits this dimension. If you seat bullets out to match the rifle's chamber, striving for the typical .010" off the leade, the rounds probably won't fit in the magazine. They will be too long. Us bolt action/single shot guys don't have to deal with that...

Anyway, that's a long-winded way of saying the only real consideration for reloading the two different cases is the powder charge. It must be reduced in the 5.56 brass to keep pressures safely under SAAMI maximums. If you have a chronograph (every hand loader should...) it is an easy matter to match velocities between your 5.56 and .223 brass. At that point they become functionally equivilent. Just keep them separate, keep track of how many firings are on each lot, and keep them properly trimmed. You will find the thicker military stuff will outlive the commercial stuff by a significant number of firings.

[legion]

So the thicker brass of 5.56 will not damage my .223 dies?

[Jeff Higgins]

Originally Posted by legion

So the thicker brass of 5.56 will not damage my .223 dies?

Not in the least.

[azasadny]

Use ample case lube when resizing and you'll be fine. I've tried RCB Case Slick, Lee Lube and Lyman's and so far the Lyman's has been the bomb diggity!