.223 vs 5.56 brass comparison

robocop10mm

Active Member
Jan 9, 2009
996
36
Round Rock
After some disagreement between myself and another member about what if there was any difference between .223 and 5.56 brass I offered to do my own comparison.

My stance is that 5.56 brass is thicker than .223 brass. Thicker brass means less internal space and less powder needed to attain a given velocity.

I took samplings of prepped brass that had been cleaned, sized, decapped and trimmed. 10 cases of each headstamp were weighed and averaged.

I
I only had a four brands of brass available for comparison. R-P and Winchester represented the commercial .223 cases. WCC-87 and LC-01 represented the military 5.56 variety. The results were not very surprising to me as R-P brass has a reputation of being softer and or not standing up to repeated reloadings like others. Winchester has a reputation as being inconsistant.

Win - Average weight 92.3 gr. Extreme spread 3 gr (91 - 94 gr)

R-P - Average weight 91.3 gr. Extreme spread 2 gr (90 - 92 gr)

WCC-87 - Average weight 92.6 gr. Extreme spread 1 gr (92 - 93 gr)

LC-01 - Average weight 92 gr. Extreme spread 2 gr (91 - 93 gr)

What do these results tell us? The differences were not as great as I had anticipated. The differences between the Win and the R-P were greater than the differences between the Win and the Mil cases. The Win cases were even heavier (thicker) than the Mil cases.

WCC-87 was the most consistant of the sampled cases. The Winchester was the least consistant. The Winchester cases were from the factory 69 gr "match" load. Not very match worthy IMHO.

The R-P was the lightest (thinnest). Perhaps the reputatuion for being "softer" is actually a result of being thinner.

I, for one, will worry less about different head stamps and more about the variences w/in a single headstamp.
 

Old Man of the Mountain

Active Member
BANNED!!!
Jan 5, 2009
327
16
Weighing cases will not prove the thickness of a brand, because the brass material used in different brands might not have the same weight, also a difference in the head design can result in a difference in weight.

In order to compare thickness you will have to measure the ID (Inside Diameter) of each brand, the OD (Outside Diameter) should be the same, but I would compare that as well.

An easy way to compare inside volume would be to use a fine ball powder, such as BL-C(2), fill a case of one brand a few times and weigh the results, then do the same with the other brand. The density of powder will vary some, so if you used the same powder over and over for testing that should keep it fair.

The cases should be trimmed to the same length, so that it is a fair comparison.

If you run the test, I would be interested in your results.
 

TSU45

Active Member
Jun 6, 2008
409
16
San Marcos, Tx
Robocop, did you just dance around the fact that you agree with me? Just kidding. I only get to rib you a little cause I saw in my email what you posted and edited.(the "diatribe")

I am impressed you really did this comparison. Your results are similar to other people who have taken the time to test it themselves. Pressure is the only characteristic of the cartridge identified by the 5.56 and .223 stamps, not brass thickness.

Although the brass isn't necessarily thicker, I think your test still might reveal a superior characteristic of 5.56 brass. Consistency. If a 5.56 spec round is at max pressure for the case, brass thickness consistency (consistency in every component really) is very important. Maybe this consistency is the reason for awarding govt contracts to quality ammo manufactures, who then stamp the 5.56. So all the good consistent brass gets stamped 5.56. I think I am rambling. Bottom line: nice study.
 

schmellba99

Member
Mar 30, 2008
88
8
Houston & San Antonio
Before 05 (I think that is the correct year), LC and other military brass was thicker than commercial .223 because the milspec for 5.56 does actually call for a thicker walled case to help the ammo take abuse from travelling, being dropped out of airplanes and pretty much any other form of handling one might find in a military environment that a commercial case might not have the ability to hold up to.

However, after 05 or 06, LC could not keep up with the demand to produce milspec ammo and has since contracted out a fair amount of ammo production for military to various commercial standards. At that time, the military actually relaxed it's milspec to allow commercial brands to produce ammo for the military and not have to waste valuble time and resources re-tooling for what amounts to a very minor change. Since then, all .223 and 5.56 brass has pretty much been uniformed into the commercial specifications because they just aren't that much different than military specifications.

Once LC is able to keep up with demand, there is talk about the military re-instating it's specs and having thicker cases.

There is a pretty good thread about all of this on thefiringline.com if you want to go find and read up about it.

In short - before 05 or 06, LC brass did have a slightly thicker wall than commercial. Since then, pretty much all of them are made to commercial spec.

LC and Winchester are pretty much uniformely understood to have the thickest brass of all commercial and military contract manufacturers. Remington is generally accepted to have the lowest quality brass of the major manufacturers.
 

robocop10mm

Active Member
Jan 9, 2009
996
36
Round Rock
Of course the study was only a comparison based on one measurable asect; weight. Yes all cases were timmed to the same length. I trim all cases to trim length to insure I get a consistant crimp. Mettalurgy was not considered. Cartridge brass is "generally" 70% Copper and 30% Zinc. Varying percentages will throw the numbers all to hell. I don't have a bandsaw available to carve up some cases to examine actual thickness. I am not inclined to cut up perfectly good cases for an experiment like this.

Take it for what its worth a comparison of the weights of otherwise identical cases. The conclusions are worth every penny you paid.
 

TSU45

Active Member
Jun 6, 2008
409
16
San Marcos, Tx
Before 05 (I think that is the correct year), LC and other military brass was thicker than commercial .223 because the milspec for 5.56 does actually call for a thicker walled case to help the ammo take abuse from travelling, being dropped out of airplanes and pretty much any other form of handling one might find in a military environment that a commercial case might not have the ability to hold up to.

LC and Winchester are pretty much uniformely understood to have the thickest brass of all commercial and military contract manufacturers. Remington is generally accepted to have the lowest quality brass of the major manufacturers.
Wow. That's different. When I think of reasoning for military vs commercial brass differences; pressures, chambers, and headspaces come to mind. Being thicker for "traveling" and "dropping out of airplanes" is a new one to me.

Think you can provide a link to thefiringline discussion you referenced? I would like to take a look at it. Have you seen this info anywhere else but the one thread you referenced?

Just have to ask because Robocop's study used '01 LC brass. Looks like LC might not be "uniformely" the thickest brass around. Just because your told over and over that something that someone heard from someone else is true doesn't mean it is. Quantitative analysis shows no correlative difference in brass thickness between .223/5.56 designations, independent of production year .
 

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