Difference between 5.56 brass and .223 brass?

coledigger4

I just picked up a cardboard box that was loaded with both 5.56 and 223 brass. While I was sorting it, I noticed a couple of split necks. I started sorting all over and found that there was a lot of 5.56 brass with split necks. I also noticed that some of the 5.56 were annealed and some were not but they were about equal as far as split necks. None of the 223 brass had split necks. Does anyone have any clues here about this? Are they that much different? I have no idea what type of firearm that these were shot through.

Wulfmann

That could also be the difference in the brass from maker to maker.

However, 5.56X45 is the military designation and there are differences compared with 223 which is the commercial designation.

The 5.56X45 has thicker brass and is loaded to higher pressures and it is recommended not to use 5.56X45 in 223 commercial guns.
When reloading it is recommended you use about 10% less charge when using NATO cases as the thicker brass means less case capacity ergo higher pressures
Some AR15s do not cycle 223 because they are lower pressure but most recent guns have been tuned to cycle both 223 and 5.56X45 NATO

Wulfmann

ammo guy

GI brass is slightly thicker than commercial brass, it usually has the annealing showing on the cases as commercial cases are polished to remove this before sale. In reloading I have found that both commercial and military brass are so close that for all practical purposes they are interchangable. Of course military brass usually has the crimped primer as well. Split case mouths may indicate the brass has already been reloaded as this is common on .223(5.56mm) brass after 2-3 resizes or that the gun used has some problem in the chamber.

coledigger4

So since the 5.56 brass is thicker and someone at some time or other has loaded it with the same amount of powder as the 223 the increase in pressure could be the cause? I have no idea how this brass was treated in the past but because it was mixed in with so much other brass I think it would be safe to say that somewhere down the line it has been reloaded. It could very well be that it has been reloaded several times and is now just 'worn out'. Thanks for the input.

sandwarrior

coledigger4,

You can salvage the 5.56x45 with unsplit necks. But, I would anneal them before I reloaded them. As long as you have enough material in the neck that will work. As they have been hot-loaded and probably not annealed in the past, they will crack if you just go and reload them. That might be a little bit of work and maybe not worth it. However, in good condition, with annealed necks you may get several more re-loadings from them.