Fatal Wound
New member
If the 223 and 5.56 cartridge are the same size they why do they head stamp each one different. Or does the diff head stamp signify the amount of powder used?
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223/5.56
- Thread starter Fatal Wound
- Start date
Marco Califo
New member
The brass is the exact same thing
The brass are the exact same. Dies in 5.56 do not exist, they use 223. 223 is used for commercial US ammo and brass. 5.56 is used by some manufacturers to describe the same thing.
U.S. military is stamped LC XX where xx is year and LC is Lake City, Mo. Army Ammo plant (currently operated by Alliant/ATK). There is NO cal designation on LC brass.
There are differences in individual rifle chambers which may be stamped 223 or 5.56. The 5.56 chamber (specifically Leade, or throat) accomodates longer projectiles.
Although the brass is the same, you need to know what rifle chamber you are loading for.
Both 223 and 5.56 are loaded to the exact same SAAMI pressure spec when you compare apples to apples. Just like dies, there is no 5.56
http://saami.org/specifications_and_information/index.cfm?page=ANSI
Three steps to safe reloading:
1. Buy a good reloading manual.
2. Read the manual.
3. Follow the manuals instructions.
The brass are the exact same. Dies in 5.56 do not exist, they use 223. 223 is used for commercial US ammo and brass. 5.56 is used by some manufacturers to describe the same thing.
U.S. military is stamped LC XX where xx is year and LC is Lake City, Mo. Army Ammo plant (currently operated by Alliant/ATK). There is NO cal designation on LC brass.
There are differences in individual rifle chambers which may be stamped 223 or 5.56. The 5.56 chamber (specifically Leade, or throat) accomodates longer projectiles.
Although the brass is the same, you need to know what rifle chamber you are loading for.
Both 223 and 5.56 are loaded to the exact same SAAMI pressure spec when you compare apples to apples. Just like dies, there is no 5.56
http://saami.org/specifications_and_information/index.cfm?page=ANSI
Three steps to safe reloading:
1. Buy a good reloading manual.
2. Read the manual.
3. Follow the manuals instructions.
Fatal Wound
New member
Thanks Marco.
It's really just which standard the manufacturer was working with, and whether or not the brass was manufactured under contract or not.
Different head stamp is because the SAAMI 223 Rem is commercial to and 5.56x45 is not. Same with 308 Win and 7.62x51, or 30-06 and 7.62x63.
Generally the NATO designation on the headstamp is meaningless without also having the "Circle Cross" symbol which means "NATO Standard." There are some countries that are not members of NATO that use 5.56 and 7.62 (Israel, South Africa) that don't put the circle cross symbol on their ammunition, but the ammo meets NATO specs for pressure curves for use in semi-auto weapons.
Of course even being NATO standard doesn't mean interoperable. American M855 or M855A1 is not safe to shoot in a Brit L85, and British Radway Green ammo will cause a US Soldier to need to re-zero for that load.
Jimro
Different head stamp is because the SAAMI 223 Rem is commercial to and 5.56x45 is not. Same with 308 Win and 7.62x51, or 30-06 and 7.62x63.
Generally the NATO designation on the headstamp is meaningless without also having the "Circle Cross" symbol which means "NATO Standard." There are some countries that are not members of NATO that use 5.56 and 7.62 (Israel, South Africa) that don't put the circle cross symbol on their ammunition, but the ammo meets NATO specs for pressure curves for use in semi-auto weapons.
Of course even being NATO standard doesn't mean interoperable. American M855 or M855A1 is not safe to shoot in a Brit L85, and British Radway Green ammo will cause a US Soldier to need to re-zero for that load.
Jimro
Flapjack23
New member
From my understanding the military designation of 5.56 indicates that the ammo was made to military spec, there are some differences from commercial ammo. The mil spec lots are tested for velocity and accuracy, not pressure. The mil spec brass is slightly thicker and weights slightly more than commercial .223. True mil spec ammo also has The case mouth annealed and the bullet and primer are sealed and as far as I know SAAMI does not publish a spec for 5.56X45. .223 ammo is manufactured to SAAMI spec for size, pressure, etc whereas 5.56 is a performance standard based on the military specification.
I have found that true mil spec ammo (5.56X45 with some type of military identifier (xm193)) is generally a hotter and less accurate round than commercially loaded .223 ammo.
For purposes of reloading, 5.56 brass has slightly less volume than .223 brass so loads should be worked up carefully as velocity and pressure will be different between the two, all other things being equal.
This is an often and sometimes heated debate.
Edit: the primer pocket is also crimped on once fired mil spec brass, that also needs to be removed prior to reloading (assuming that is your intent based on where this post is located)
I have found that true mil spec ammo (5.56X45 with some type of military identifier (xm193)) is generally a hotter and less accurate round than commercially loaded .223 ammo.
For purposes of reloading, 5.56 brass has slightly less volume than .223 brass so loads should be worked up carefully as velocity and pressure will be different between the two, all other things being equal.
This is an often and sometimes heated debate.
Edit: the primer pocket is also crimped on once fired mil spec brass, that also needs to be removed prior to reloading (assuming that is your intent based on where this post is located)
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Marco Califo
New member
For purposes of reloading, 5.56 brass has slightly less volume than .223 brass so loads should be worked up carefully as velocity and pressure will be different between the two, all other things being equal.
This statement is false. It is dis-proven here:
http://www.accurateshooter.com/cartridge-guides/223rem/
This is an old wives tale repeated without factual basis. Some bullet makers even fall prey to this myth and repeat it (Barnes is an example). But it is not true.
That statement WOULD be true of commercial 308 versus Lake City 7.62 where there are this, and other, significant differences in brass by manufacturer.
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If the 223 and 5.56 cartridge are the same size they why do they head stamp each one different. Or does the diff head stamp signify the amount of powder used?
Its done to confuse the consumer and keep the internet myths alive.
That statement WOULD be true of 308/7.62 where there are this, and other, significant differences in brass by manufacturer.
It would be "sort of true" in that some milsurp 7.62 brass is thicker (less internal volume) than some commercial brass. But there have been so many manufacturers of 308 Win brass and 7.62x51 brass over the years that the two overlap significantly.
Even top end commercial brass manufacturers vary in internal volume between lots, and between machines on the same lot....
Suffice to say, I don't worry about brass being thicker. I just start at the starting point and it has never been "too hot" just yet. Work up to where accuracy is good, and then stop. That starting load (or calculated starting load by reducing 10%) is there for a reason.
Jimro
Fatal Wound,
.308 Winchester and .223 Remington are commercial names for commercial versions of the military cartridges. The U.S. military developed them first. The military named the final versions 7.62 NATO and 5.56 NATO because 7.62 mm and 5.56 mm are the metric measures of .30 and .22, the bore diameters for barrels for these cartridges. This was a nod to the fact these were to be universally used and interchangeable NATO country cartridges and most NATO countries use the metric system rather than the inch system of measure. The various military gun designers use slightly larger average chamber dimensions to improve automatic weapons fire feed reliability. The military chambers also typically (except some sniper systems) have slightly longer throats in order to accommodate some specialty loads.
The bottom line is that SAAMI got reference loads from the military and measured them on the SAAMI style instruments and the results became the standard for the civilian version rounds.
Flapjack23,
I'm afraid someone has sold you some erroneous information. Typically, 7.62 NATO military cases tend to be heavier than most commercial .308 cases, but in .223/5.56 NATO, the military cases are the ones that tend to be on the lighter side. Also in the old .30-06, the military cases, at around 195 grains, tend to be in the middle of the range of commercial brass weights, which have run from an extreme low of about 177 grains to as high as 214 grains over the years.
There are lengthy tables of measured case weights and water overflow capacities for the 5.56/.223 at the 6mmBR.com site (scroll down about 1/3 of way, here). My own measurements involve a smaller number of headstamps, but get essentially the same results as theirs when the headstamps match.
I don't know who told you the military doesn't measure pressure? They do not want guns blowing up when they are needed most. They not only measure chamber peak pressure, they go beyond what SAAMI standards do by also measuring gas port pressure. They also have a maximum ignition to bullet exit time requirement that SAAMI does not. The way they decide if a lot of procured powder is even suitable for a particular load application is it has to produce gas port pressure within the specified pressure window while simultaneously producing velocity within a specified velocity window (about three times tighter than the SAAMI standard velocity for the same bullet weight), and do all that without exceeding the peak chamber pressure limit.
For the U.S. military loading are SCATP 7.62 and SCATP 5.56. These standards use the same conformal piezo transducers for pressure that SAAMI has been gradually superseding copper crushers with, and have the exact same maximum average pressure (MAP) limits SAAMI uses for .308 and .223 as measured by the same type of piezo transducer. European NATO member countries use the EVPAT standard to produce the functionally identical ammunition, but use a channel piezo transducer sampling gas at the case mouth area of the chamber to determine pressure. The 7.62 readings from both instruments are close to the same for a maximum pressure cartridge, but in 5.56/.223 the conformal transducer reads lower than the channel transducer. A reference load that measures 55,000 psi on the conformal transducer measures 63,366 psi on the NATO type channel transducer. This disagreement is the result of a number of technical differences in the measuring methods, but as long as those numbers are used with each instrument type, you end up loading to the same absolute pressure and the ammunition is cross-compatible between U.S. and European guns chambered for the same cartridge. In other words, the U.S. made and European made rounds can be swapped out in each others weapons with no change in function or sight settings required. That's the objective of standardized NATO ammunition.
You can download the declassified MIL-C-46931F spec to look at how this was done using copper crushers before the piezoelectric transducers came along and took over. You will find the accuracy requirement in it, but also all those other requirements for pressure limits and some requirements more I didn't bother to mention.
.308 Winchester and .223 Remington are commercial names for commercial versions of the military cartridges. The U.S. military developed them first. The military named the final versions 7.62 NATO and 5.56 NATO because 7.62 mm and 5.56 mm are the metric measures of .30 and .22, the bore diameters for barrels for these cartridges. This was a nod to the fact these were to be universally used and interchangeable NATO country cartridges and most NATO countries use the metric system rather than the inch system of measure. The various military gun designers use slightly larger average chamber dimensions to improve automatic weapons fire feed reliability. The military chambers also typically (except some sniper systems) have slightly longer throats in order to accommodate some specialty loads.
The bottom line is that SAAMI got reference loads from the military and measured them on the SAAMI style instruments and the results became the standard for the civilian version rounds.
Flapjack23,
I'm afraid someone has sold you some erroneous information. Typically, 7.62 NATO military cases tend to be heavier than most commercial .308 cases, but in .223/5.56 NATO, the military cases are the ones that tend to be on the lighter side. Also in the old .30-06, the military cases, at around 195 grains, tend to be in the middle of the range of commercial brass weights, which have run from an extreme low of about 177 grains to as high as 214 grains over the years.
There are lengthy tables of measured case weights and water overflow capacities for the 5.56/.223 at the 6mmBR.com site (scroll down about 1/3 of way, here). My own measurements involve a smaller number of headstamps, but get essentially the same results as theirs when the headstamps match.
I don't know who told you the military doesn't measure pressure? They do not want guns blowing up when they are needed most. They not only measure chamber peak pressure, they go beyond what SAAMI standards do by also measuring gas port pressure. They also have a maximum ignition to bullet exit time requirement that SAAMI does not. The way they decide if a lot of procured powder is even suitable for a particular load application is it has to produce gas port pressure within the specified pressure window while simultaneously producing velocity within a specified velocity window (about three times tighter than the SAAMI standard velocity for the same bullet weight), and do all that without exceeding the peak chamber pressure limit.
For the U.S. military loading are SCATP 7.62 and SCATP 5.56. These standards use the same conformal piezo transducers for pressure that SAAMI has been gradually superseding copper crushers with, and have the exact same maximum average pressure (MAP) limits SAAMI uses for .308 and .223 as measured by the same type of piezo transducer. European NATO member countries use the EVPAT standard to produce the functionally identical ammunition, but use a channel piezo transducer sampling gas at the case mouth area of the chamber to determine pressure. The 7.62 readings from both instruments are close to the same for a maximum pressure cartridge, but in 5.56/.223 the conformal transducer reads lower than the channel transducer. A reference load that measures 55,000 psi on the conformal transducer measures 63,366 psi on the NATO type channel transducer. This disagreement is the result of a number of technical differences in the measuring methods, but as long as those numbers are used with each instrument type, you end up loading to the same absolute pressure and the ammunition is cross-compatible between U.S. and European guns chambered for the same cartridge. In other words, the U.S. made and European made rounds can be swapped out in each others weapons with no change in function or sight settings required. That's the objective of standardized NATO ammunition.
You can download the declassified MIL-C-46931F spec to look at how this was done using copper crushers before the piezoelectric transducers came along and took over. You will find the accuracy requirement in it, but also all those other requirements for pressure limits and some requirements more I didn't bother to mention.
UncleNick is way smarter than I am about specs of NATO and other ammo. But as a hacker with a few years reloading experience I have noticed a couple of things about 223 and LC brass. One is that weight alone is not a reliable indicator to compare volume because different brass are made of different alloys. I have weighed commercial brass that was heavier than LC brass, and of course LC varies from lot to lot. I expect this type of difference happens between manufacturers brass as well. To be clear, just because 2 pieces of brass with different headstamps weigh the same do not assume they are identical in volume. May or may not be.
Since 223/556 are small, here is a volume shortcut. This is simply a quick visual to compare 2 pieces of brass for volume. Just charge both with the same powder charge and visually compare how full they are. With this small brass it does not take much difference in volume to be visually apparent.
I load exclusively LC brass since I got a lifetime supply on an auction once. The prep takes a little work since the primer crimp has to be reamed out and they are usually at maximum trim length of over so I automatically trim when I prep a batch. After the first prep job I find them to be durable and have had no feeding or headspace issues. I keep them in lots and when they have been fired enough times for signs of fatigue to start showing in more than 1 or 2 I throw the whole lot in the scrap bucket and start over.
Since 223/556 are small, here is a volume shortcut. This is simply a quick visual to compare 2 pieces of brass for volume. Just charge both with the same powder charge and visually compare how full they are. With this small brass it does not take much difference in volume to be visually apparent.
I load exclusively LC brass since I got a lifetime supply on an auction once. The prep takes a little work since the primer crimp has to be reamed out and they are usually at maximum trim length of over so I automatically trim when I prep a batch. After the first prep job I find them to be durable and have had no feeding or headspace issues. I keep them in lots and when they have been fired enough times for signs of fatigue to start showing in more than 1 or 2 I throw the whole lot in the scrap bucket and start over.