.223 with 5.56 brass

[squirrelshooter]

I recently ran out of .223 bras and I’m stocking the shelves in my ammo locker. I do have a pile of 5.56 brass that I kept aside. If I resized this with a .223 die and loaded it to .223 spec’s would I be risking disaster? I seem to think I’d be alright. Anyone with first hand knowledge?

 

[BattleRife]

There is no inherent difference between the two. Most makers will crimp the primer pocket on 5.56mm brass, you will have to deal with that. Some manufacturers may draw their cases to have a little more or less capacity than others, but that is a product of their tooling, not the cartridge. They may well take cases off that line and put either marking, .223 or 5.56, on them.

 

[45C]

It always worked/works for me.

 

[Redblack]

No issues using the brass. Just extra work to remove the crimp and priming.

 

[supernova]

Yes, use 223 data. There is no risk. You will most likely have to remove primer crimps and possibly uniform the pockets but for all intents and purposes it is essentially bulk 223 made for a different customer.

 

[StoneHorse]

This is a question, not a statement. Is 5.56 brass a little thicker walled than .223 brass, reducing case capacity slightly?

 

[BattleRife]

This is a question, not a statement. Is 5.56 brass a little thicker walled than .223 brass, reducing case capacity?

No. Some people have reported certain brands have thicker walls, but that seems to be a product of who made it, not the caliber marking.

 

[StoneHorse]

Thanks.

 

[calibrecarstairs]

 

[bearhunter]

This subject has been beaten to death several times on this site and others.

I suspect the OP is using IVI brass, left behind at his range by police, after their practice sessions??

IVI brass does tend to be a bit thicker and weigh more than most commercial brass.

This is what I did.

First I clean the brass cases to my normal standard, which doesn't include polishing, but does include washing in a good detergent, like Lemshine and water.

Let the cases dry, lube and deprime.

Then, chuck up a countersink bit, either in a drill press or hand drill and decrimp the edges of the primer pockets and the inner edges of case mouth. Usually the case mouths have had some sort of crimp on them as well and I have a reverse angle bit, I purchased from Amazon, to clean up the outside of the case mouths.

After this is done, I prime a few cases and weigh them empty, then record this on the side with a felt pen, record the weights with the top of the miniscus just even with case mouth and record the weight on the side with a felt pen.

Total up all the empty weights and compute an average, then all of the full weights and do the same.

This will give you the average of the water capacities and you can calculate how much difference there will be in your powder charge between the commercial cases and the milspec cases.

I usually do ten cases.

Then, I weigh ten commercial cases in the same manner and compare their water capacities.

The commercial cases will usually hold more water than the milspec cases.

Divide the weight of the water in the milspec cases by the weight of the water in the commercial cases multiply your normal load for the commercial cases. The result will usually give you a load that is very close to duplicating the performance of the commercial load in a milspec case.

One thing, if you intend to trim your cases to uniform lengths, do so before weighing them.

 

[bigedp51]

As you can see below Lake City 5.56 brass is harder and not thicker.

 

[FortHunter]

I've had zero issues using 5.56 ivi brass in my .223 bolt gun. A surplus of ivi brass was the excuse I used to buy the gun.

 

[Maple57]

I'm so tired of such ridiculousness.

Before repeating this nonsense, please go weigh your 556 cases and compare them to 223 by Lapua.

Heavy cases are not "reserved" for the military. Its just a brand specific variation.

But yes, a hand loader should be mindful of his brand of brass whether 223 or 556, but no credence should be noted other than a slight compensation on the high end for heavy cases.

 

[squirrelshooter]

Thanks guys. I’ll go ahead and reload them. Thanks for the internal volume charts. Interesting stuff!

 

[bearhunter]

OP, the information you got here doesn't just apply to the 5.56/223 cases.

It applies to all cases, whether they are milspec or commercial.

Medium cartridge cases and larger seldom pose a problem

It's the small cases that can cause issues. Very slight differences can significantly influence pressures when loading "small" cases.

The 5.56/223 case is on the cusp IMHO and even though you need to be careful, you will have a bit of leeway.

As always, the best advice is to start with a minimum load to determine if your load combination will be handled safely by your rifle.

 

[junkdude]

Yes, beaten to death

The brass walls really don't contribute in any significant way to pressure containment, that's what the chamber does. The case is just a means to hold everything together to get it into the chamber, then it only acts as a gasket, the head of the case does contain some pressure.