.223 rem & 5.56 reloading question

[Sgt_Wade]

I am brand new to reloading. Just set up my RCBS press and have used hornady brass (brand new) for 6.5 creedmoor. I didn't have any issues doing that. My question is this. I have tons of spent 5.56 brass that I kept for reloading when I finally got into it; can I used .223 rem rcbs or hornady dies to make .223 rem ammo out of 5.56 brass or do I have to get brand new .223 rem brass??

Thank you all, I appreciate your expertise. I haven't found a direct answer via google.

[Unclenick]

Welcome to the forum.

You are good to go. I've looked at the military and SAAMI cartridge drawings and the case dimensions are the same on the outside, so the same sizing dies work fine with both. The only exception is that every once in a while you run into a self-loader that wants the brass sized extra small to feed smoothly, and for those you need a small base die. But I've never owned a rifle like that myself. Some military brass is harder, so have a good sizing lube. But except for a couple of foreign brands, the case capacity in .223 and 5.56 is also about the same (unlike .308/7.62, for which military brass tends to be a little less roomy inside), so they are interchangeable.

The only thing to watch out for is that military 5.56 brass, and some civilian .223 brass will have crimped primers to prevent the primers coming out when firing in a machine gun. You need a tool to remove the crimps after decapping or you may have some problems seating primers. Sometimes you can get away with it, but it can be hard and at other times it can't be done.

[Rangerrich99]

What Unclenick said.

[Sgt_Wade]

Awesome thanks for that information. I enjoy the process and the learning that is involved. Thank again and I will be asking many more question I am sure, when they arise.

[mkl]

Just be sure to remember what UncleNick said:

The only thing to watch out for is that military 5.56 brass, and some civilian .223 brass will have crimped primers to prevent the primers coming out when firing in a machine gun. You need a tool to remove the crimps after decapping or you may have some problems seating primers. Sometimes you can get away with it, but it can be hard and at other times it can't be done.

Search the many threads on this forum re removing the military crimp.

[cw308]

Being the 5.56 brass is thicker , my want to lower the listed charge by one grain . Start lower is always the safe way . I shoot 308 and I like the brass that's on the thick side , even medium loads will fill the case .

[std7mag]

As Unclenick said, just remove the crimp.
Someone had recommended using Lake City brass for my wife's 223. More volume actually, more consistant weight.
I'm shooting 69gr MatchKings with Alliant Power Pro 2000.
Good velocities, temp stable, and low Extreme Spread and Standard Deviation.

[Unclenick]

cw308,

As std7mag says, the 5.56 military brass is not thicker than .223. This shows just the opposite (scrollbar about 1/3 of the way down). In .30-06 the difference is so small as to be negligible except for some lots of Winchester brass that have more capacity. It is only 7.62 that is heavier and thicker than .308, and if you follow some of member Metal God's recent posts on .308 brass capacity (in this thread), the difference has been getting smaller over time, with the lightest commercial cases gradually getting a bit heavier.

[Sgt_Wade]

Dang...I'm glad I joined. Holy cow yall know so much. Great resource. I am learning so dang much it's insane.

[Tsquared]

My favorite brass is the Lake City 5.56 NATO. It does require a bit more case prep due to having to ream the primer pocket to get rid of the crimps but it has a bit more volume and it seems to be more durable.

[mgulino]

What UncleNick, and others, have said.

I also load .223 and use a mix of .223 and 5.56 brass. I also will sort the brass. 5.56 is a bit thicker (can't measure the thickness, but 5.56 cases weigh more than .223 cases). If outside dimensions are equal, that means inside dimensions must be different...5.56 having less case capacity...meaning higher pressure with the same powder charge, bullet weight and seating depth.

I usually back off on the powder charge a grain or so with 5.56 brass.

[cw308]

I would check case thickness off the case neck in two locations 12 & 6 o'clock . Same as when checking neck tension .

[m&p45acp10+1]

If you plan on doing more than just a few cases at a time. I advise getting a primer pocket swage. The bench top models are a one time expense of around $100.00. Some case prep kits have a reamer that does work. Make sure if you chuck it in a drill that is on low RPM setting. I have the swage that goes on my RCBS press. When finances allow I will order one of the bench top models so I can mount it to a length of 2x6, and clamp it to a table to do the work while sitting down.

[gwpercle]

As long as we are talking about primers...Learn the difference between Boxer primers
and Berdan primers . I learned the hard way about them.

Even after swaging the crimp on military cases the brass will do a little spring back , use a Primer Pocket Uniforming Tool , to finish the job and cut away that last little bit that makes it hard to seat some primers. Then you will be good to go.
Gary

[Unclenick]

Originally Posted by mgulino

5.56 is a bit thicker (can't measure the thickness, but 5.56 cases weigh more than .223 cases). If outside dimensions are equal, that means inside dimensions must be different...5.56 having less case capacity...meaning higher pressure with the same powder charge, bullet weight and seating depth.

No. It really doesn't necessarily mean that. The difference in brass weight is often explained entirely by case head tolerances and by use of different brass alloys with slightly different densities. The width of the head and the extractor groove relief angle and the rim thickness have tolerances and different makes can be at different ends of that tolerance range. Since the head is only the solid part below the bottom of the inside of the case, head tolerance-based weight differences have no effect on internal capacity.

If you follow the first link I provided in my last post you will see measured case weight and case water overflow capacities proving the above. In their samples, WCC99 5.56 brass weighed 95.5 grains and had 30.5 grains of water capacity. New Lapua weighed 2.1 grains less, at 93.4 grains, but had only 30.1 grains water capacity. Based on average brass density, if that difference had been in the case walls the water capacity would have been about 30.74 grains instead of 30.1 grains.

Overall, the weight and capacity changes do tend to be monotonic (go together), but on a case-by-case basis, it just isn't automatically true. I tried to take advantage of the monotonic correlation to predict case water capacity differences for a number of differently headstamped .308 cases once, but I could only get the least squares fit to predict the actual capacity differences to an accuracy of about ±20%. That 40% span is not very tight.

In the table at the end of that link, Lake City '06 and WCC99, both military brass, had more capacity than any other cases measured.

[mgulino]

I stand corrected by UncleNick. I'm not a newbie, but I don't have many years of experience to fall back on either. I can admit when I'm incorrect.

So, the question is this.
Can I use fired brass, re-sized without popping the used primer and trimmed to the same length, and measure the weight of water the case can hold?

Assuming water from the same source, water is water; therefore, the volume and weight of water for each case would be different.

Comparing water weights would yield case capacity for each headstamp.

[thallub]

can I used .223 rem rcbs or hornady dies to make .223 rem ammo out of 5.56 brass or do I have to get brand new .223 rem brass??

Yes.

My advice:

1. Get a large quantity of LC 5.56mm brass.

2. Full length resize and de-cap the cases.

3. Remove the primer crimp.

4. These cases have long necks. Trim to length.

[Unclenick]

Thallub,

He's wanting to leave the expended primer in so water doesn't leak out when he fills them. You can, however, drip candle wax in to plug an empty primer pocket and knock it out with a decapping pin later. If it is too soft, pop it in the freezer. I've also pulled the anvils out of spent primers and flattened the bottoms of the cups with a large drift punch before.


Mgulino,

I've sure had to admit to numerous errors over time myself. There shouldn't be any ego interference with that. You only know what you know, and over time my memory isn't what it was, either. I heard recently that every time you remember the same thing, you are actually remembering your last time remembering it and not the original memory and you tend to modify the memory by iteration over time. The more often you remember it, the less accurate it becomes. Therefore, if you remember a fact often enough, eventually you should look it up again to be sure. The irony of the memory mechanism is that people with amnesia, therefore, have the least corrupted memories, if only they could gain access to them again.

What you are proposing will find the resized case capacity. The terms to watch are case water capacity and case water overflow capacity. The former is the amount of water space under a loaded bullet, while the latter is the weight of water level with the case mouth with no meniscus, so, despite its name, no actual overflowing is involved. But it's the one you want, cases sized and trimmed after sizing so they are all the same length from head to shoulder and from head to mouth.

Or...you could just use as-fired case water overflow capacity. When a gun fires, the case expands to seal the chamber, and high power rifle does it with enough pressure that the case fireforms to the chamber, the as-fired case water overflow capacity tells you what the case volume was when the pressure peaked and is the number that affects peak pressure. Indeed, you can think of your resizing die as a sort of tight chamber. Whether you compare resized or as-fired capacity, unless there are bent case mouths or other ejection dents, the difference in case water overflow capacity should match.

Water as a volume standard was originally used at very slightly less than 4°C (3.982078°C, or 39.169054°F), which is the temperature at which liquid water is most dense; as close to 1 gram/cc as it gets, to the best of our ability to measure. (The calculators say 1.000000000063067, or exactly that number of grams/cc, but I have trouble believing that level of precision). At room temperature of 72°F, its density drops to 0.99772 g/cc, but for any temperature, use this calculator to find a precise number. Divide your water weight by that number (or the calculator's) to get a weight that can be converted directly to cubic centimeters by dividing by 15.432358 (aka, the conversion factor between grains and grams).

[std7mag]

I'll go wat out on the skinny limb here and disagree, with a caveat.
IF it was once fired out of YOUR rifle, then yes.

If it's range pickup, then no.
Possible difference being the difference between chambers.
If the first shooter has a "loose" chamber in their 5.56 and the chamber in your 223 is on the tight side, you could run into pressure issues.
Or light loads if opposite.
Assuming your neck or collet sizing. If you full length size ( recommended for pick up brass) then plan on neck sizing your volumes will be different.

[Unclenick]

Agreed. My assumption was his gun as the OF (original firer; I just made that up).

[thallub]

Sometimes i re-load unsorted brass. Last batch included Winchester, Remington and numerous lots of LC cases. Fired five groups of five unsorted rounds each through my Remington 700 at 125 yards. Average group size was just over 1 1/4 inch. My carefully crafted and sorted accuracy loads average 3/4 inch at 125 yards.

i've used nearly every brand of brass available including the expensive stuff that IMO ain't worth the money. Best brass i've found is one lot of 5.56mm M193 head stamped TW 67.

[603Country]

A few years back, I was trying out several Resizing die types (std, Nk, Collet, Bushing) to see what gave me best accuracy in my 223. At the end of my testing, as I was putting things away, I realized that I had a big sack of mixed headstamp brass, and I wondered how the accuracy of the ‘chosen’ load in mongrel brass compared to accuracy in the sorted cases. So I loaded up the mixed brass and shot them a bunch. At the conclusion of that non-scientific test, I found that the mixed headstamp brass shot quite well, though not as well as the single headstamp brass. For hunting purposes, I don’t think you could tell the difference. There were a few more flyers with the mixed brass. And maybe the fact that the mixed brass had been shot and reloaded more than the single headstamp brass had would explain away some of the slightly worse accuracy.

After all of that Resizing and shooting, because someone may be wondering what conclusion I finally came to, I decided to Partial FL Resize (reset the case shoulder to best fit the rifle chamber). One thing I did not test at the time was to resize with a Redding Body Die and then size the case neck with the Lee Collet Die. I suspect that might be the absolute best way for zero runout and max accuracy, and I think Unclenick does it that way.

[Unclenick]

^^^That's an important point. Most people think errors always open a group up in general, but some sources of error can actually just produce intermittent fliers and the rest of the group looks just as tight as ever, misleading the shooter to believe he is making uncalled errors when he is not. That's what happens when a barrel first reaches the point it is shot out. It can happen with unsorted cast bullets when and occasional casting inclusion unbalances the odd particular bullet. It can happen in cases where an unusually uneven level of neck wall runout will occasionally be produced. I had a batch of Winchester .308 brass in which just one out of 1000 had total indicated neck wall runout of 0.008". The next highest was just over 0.004". That's enough to toss a bullet half a moa off the intended POI.