223 vs 5.56 cases

[lokidansk]

I've been using Fed LC 5.56 brass with cci 41 primers, 23g of win 748 under 77g SMKs and TMKs with great results for a couple of years. I've got a bunch of prept and primed 223 rem cases, in yalls opinion do you think I'll get the same results with the 223 as with the 5.56? Cases are prept identically.

Thanks

 

[Unclenick]

Yes. There's no difference in the brass except that the heads on military brass can be harder than on some commercial brass, so the rims don't bend as easily. But the dimensions of .223 Rem and 5.56 NATO brass are the same. It's the chambers that differ.

See this article. It compares brass about a quarter of the way scrolled down.

 

[Jimro]

As long as you do the load workup the same way and stop when you get the same results, yeah, you should be fine.

LC case volume varies from year to year/lot to lot, so your Rem 223 brass is probably going to be just a tad different from what you are used to, but there shouldn't be any reason to not get good accuracy results.

Jimro

 

[Metal god]

Yes and no , yes your 223 cases should produce just as accurate loads as the 5.56 cases . No that same load may not produce the same accuracy in a different case . You may or may not have to tweak it a little to get the same results .

Jimro posted while I was typing but yep I agree

 

[NorthernBlue]

I just did a load of Lake City 2016 vs Remington .223 brass. 10 rounds each. There was no difference in velocity or pressure signs. I was loading 25.5 gr of H335, lit buy a CCI 450, pushing a 60 VMAX our of a 16" 1-8 twist 5.56 chambered AR15.

 

[steve4102]

I just did a load of Lake City 2016 vs Remington .223 brass. 10 rounds each. There was no difference in velocity or pressure signs. I was loading 25.5 gr of H335, lit buy a CCI 450, pushing a 60 VMAX our of a 16" 1-8 twist 5.56 chambered AR15

What did you use to measure the pressure?

 

[Jimro]

"Pressure signs" is not the same thing as "measuring pressure."

The classic way is to "read the primer" or measure case head expansion. If you get a flattened primer or cratered primer, pressure is too high. If you get case head expansion, pressure is way too high.

Pressure signs are danger signs, not a valid way to measure the pressure of a load as most centerfire brass won't show pressure signs until well past SAAMI max average pressure.

Using the same primer, bullets, and powder in two different brands of brass may create a condition where the pressure is different, but not different enough to trigger a pressure sign in the primer or case head.

Jimro

 

[Metal god]

I just did a load of Lake City 2016 vs Remington .223 brass. 10 rounds each. There was no difference in velocity or pressure signs.

That's cool , I like it when I find stuff like that . Make sure you note that .

I use LC brass almost exclusively in 223/5.56 . I also have a large lot of mixed brass and I recently prepped 500 cases of the mixed stuff and loaded it with a confirmed good load combo that I shoot in some LC-12 &13 brass . The LC loads shoot right around 1 moa . The mixed brass loads shot right around 2.5 moa .

When loading those mixed brass cases I noticed every once and awhile the charge would fill a case much more then the others ( almost to the point of over flow) . It turned out every case that almost had the over flow also had the same head stamp CBC .

I went ahead and seated the bullets in the CBC cases and separated those out from the rest . At the range I compared the velocities of the CBC loads to the LC loads . This was a 7 or 8 shot test and the CBC loads averaged 90+fps faster then the identical LC load . When I got back home I measured the case volumes of the CBC cases and the LC cases . The CBC cases averaged 2.3gr less H2o then the LC cases .

Because of these limited test I've done , IMHO mixing cases will effect accuracy as well as ES/SD .

 

[Unclenick]

That's a good heads-up on the Brazilian brass. While it is true the LC and commercial domestic cases all change some from one lot to the next, they don't typically change enough to cause you to adjust your load. If you have a good sweet spot load, you should be able to span at least 0.6 grains of charge weight (±0.3 grains) without seeing any significant group size change. That's close to 1 grain difference in water capacity or 8.5 grains of case weight difference when all of that difference is in the body portion of case or internal head height and none is due to differences in head diameter or other head dimensions. The tables I linked to on 6 mm BR showed only 0.8 grains water capacity difference between all the cases in their table except the Lapua Old Lot case at the bottom of the list, which weighed 104 grains and had a big drop down in capacity of 1.8 grains from that of the next larger capacity case on the list. It sounds like the Brazilians are following that old design.

 

[Metal god]

To be fare with full disclosure . When I said I prepped the mixed brass I should have added that they were not prepped the same as the LC cases . I use Redding bushing dies for most of my rifle calibers I load for . How ever on the mixed cases I used my Lee die set . Now I used my competition shell holders so my case head space was the same as the LC cases but bullet hold had to have been different . The other thing that was different was that I de-burr the flash holes on all my rifle brass EXCEPT for the mixed brass I loaded .

I've always separated my brass but wanted to see if I could load some mixed brass loads I'd be happy with . The reason I used the Lee dies was if I were to like the result I'd start loading 223/5.56 on my Lee classic turret press . I know I could use my Redding dies in the turret press but they are already set up to be used in my Hornady single stage that uses the quick release bushings . I don't want to have to move my dies around constantly adjusting them .


I guess my accuracy differences could have been due to the case prep .

If you have a good sweet spot load, you should be able to span at least 0.6 grains of charge weight (±0.3 grains) without seeing any significant group size change.

I don't agree with that , ya that's right i disagree with Unclenick . (snicker)

.6gr in 223 is huge IMO and i often see groups change in that increment . Could you have a load that is that forgiving , sure . Can it be expected or even normal , I say not likely . Maybe larger cases like 308 , 30-06

 

[JeepHammer]

OK, we are talking AMERICAN MADE brass here...
There has been very little difference between manufacturers for years,
The difference was with military (5.56 NATO) brass early on, 5.56 used slightly thicker case walls, which reduced volume SLIGHTLY.
Military used 'Hotter' ball powder, pressures/vocities were comparable.

Since ATK/Federal took over the Lake City ammunition plant from Winchester/Olin,
And since the HUGE homeland security contract that caused shortages,
In 2012 ATK got the military standards changed to EXACTLY the same as .223
No case wall thickness difference or weight difference...
Which SCREWED those of us sorting military/civilian cases by weight!

The zinc/copper/tin/trace minerals slightly differ from manufacturer to manufacturer, and weight changes SLIGHTLY, but the cases are as close to the same as anything mass produced can be.

If you have much older military cases, or imported cases, its a crap shoot...
Most of the time, if you recognize the head stamp, you won't be able to tell the difference between cases.

The ATK/Federal military cases really took a step up in terms of the brass composition. The old Winchester/Olin cases weren't the best for reloading, too much tin,
But the newer military cases polish up, anneal, form just like upper quality civilian cases do.
It wasn't Winchester/Olin's fault, until the second wars in the Middle East the government simply wouldn't allow them to upgrade, change the brass formula.

 

[Unclenick]

Metal God,

I think you missed my point. The 0.6 grain span (±0.3 grains) is based on what powder dispensing equipment may be relied upon to provide (especially in a progressive press), not on the size of the cartridge. Just because the .223 Rem case has half the powder capacity of a larger cartridge doesn't mean your scale or powder dispenser suddenly develop twice the resolution and dispensing precision when you are loading for it. You need a load to span enough powder charge that the standard deviation of your powder dispensing method's error doesn't move you off the sweet spot. I figure I can reliably hold ±0.2 grains with volumetric dispensing, and like to allow another tenth for temperature changes and the like. Usually my volumetric dispensing is within 0.1 grains for spherical powder and 0.2 grains span with stick, but I know that it's on a bell curve with a standard deviation and that every once in awhile will randomly throw one out that is double that error, and going into denial won't change that. If I can't achieve the 0.6 grain span objective, I figure the load is too touchy for variable conditions and I experiment with other powders or primers until I find something that does what I want.

By the way, a 0.6 grain accuracy span isn't especially rare. I had a load for the 168 grain MatchKing using the now defunct Brigadier 3032 powder in the .308 Winchester that grouped well at 100 yards over a whopping 2.5 grain charge weight span in my M1A. Hatcher wrote of a coarse grain powder that the Frankford Arsenal loading equipment could only dispense into 30-06 with an accuracy of 1.7 grains (±0.85 grains), but that was used to set a number of records at the National Matches. So wider span loads than you might expect can be remarkably consistent as far as where the bullet prints. You just need to be looking for one. Once found, you get the best immunity to changing conditions as well as to minor dispensing variation.

In finding these loads, powder selection often is key. I can look for a powder that minimizes velocity change with charge weight error for my bullet. For example, suppose I want to shoot a 55 grain bullet in the .223 Rem. IMR 4895 is a powder I always have on hand, but looking at Hodgdon's data, IMR 4895 changes the velocity of a 55 grain bullet by about 112 fps/grain when adjusting the charge weight, but Varget changes it only 62 fps/grain. So using Varget instead of 4895 cuts down on the error a given amount of charge weight makes and if I choose that, I've got as much consistency in the little round from a 0.6 grain span that I get from 4895 in the .308 Win or the 30-06, give or take. This difference in powder behavior changes with bullet weight, so you have to go through the choosing process for every bullet you want to shoot. It also means there are likely to be fewer powders that meet my minimum weight span criteria in the .223 than in the 30 cal rounds, but careful selection and experimenting will usually get you there.

 

[Metal god]

I did not realize you were speaking of a powder measure . I also agree that .6gr may have no effect in some cartridges especially the larger the cartridge gets . My rule of thumb is 1% of charge is the least amount that will effect any cartridge . Meaning if you have a charge weight 52gr . Anything less then .5gr is not likely going to show any real/noticeable difference in accuracy . So a 223 will be in the 25gr charge area and anything less then .3gr is going to be hard to discern . Although that's not 100% accurate across the board but I believe it's a reasonable assumption .

I agree that the component combo has a lot to do with the differences you may see from charge to charge . I just did two load developments in 223 that had all duplicate components except the powders . The powders were CFE-223 & AR-comp . These were both worked up in .5gr increments ( which I should have done in .3gr increments ) either way both powders shot about the same sized smallest group . How ever the AR-comp shot all the 5 shot groups as a whole smaller then the CFE-223 . I did not Chrono them

 

[Stats Shooter]

Metering........Metering out of my powder dispenser is one of the criteria I have for selecting a powder. It is why I use Benchmark, and CFE-223 for bulk AR Ammo in both .308 and .223. Because they both meter within .1 Grains +/-. When making Bolt action ammo, I weigh each charge so I am more concerned with how much space the powder occupies.

For instance, I find that in my .270 win, I get much more consistent velocities using H4831 rather than 4831 SC because the regular H4831 completely fills the case and is slightly compressed while SC leaves some space and tipping the cartridge up or down before loading makes a bit of a difference. (about 30 fps in a 3000 fps load). But regular H4831 meters horribly because it is such a long stick powder so if I was making it in bulk, I would use H4831 SC.

I also find the best load in my .300 Win Mag using 81 Grains of H1000 and 180 Grain Nosler Accubonds, 1/2 MOA at 300 yards, 3050 FPS and H1000 is a poor metering powder. But it is a compressed load

 

[Unclenick]

Mississippi,

This stuff can fool you, though. I mentioned earlier that Hatcher found a powder that could span 1.7 grains in .30-06 and made accurate match loads. The whole story is that the powder was a long stick powder (probably IMR 1186, which is no longer made, but which had grains the same size as IMR 4064) and he was choosing it over another, similar burn rate rate powder with shorter grains that the same loading equipment could hold to a span of just 0.6 grains, more than twice as accurate. Nonetheless, in testing from machine rest rifles the less precise long grain powder load consistently produced tighter grouping. Group size would have been tested at both 600 and 1000 yards back then.

Today, both Mk. 316 mod. 0 sniper ammunition and Federal GMM match with Sierra MatchKing bullets is loaded with IMR 4064. I've pulled the .308 Win GMM with 168 grain SMK's and found at least 0.4 grain spreads from shot to shot inside the same box. The thing that happens is coarse grains can settle a lot, and when they do the metered volume weighs more. But at the same time, the greater crowding of space tends to slow ignition by interfering with passing of the flame front more, so the more tightly packed powder mimics the characteristics of a having a slower burn rate. In other words, with some bullet weights that packing variation can self-compensate for weight errors.

The bottom line is I don't automatically reject a powder because it doesn't meter as well as another. I test the less even loads and sometimes, as with IMR 4198 in the triple deuce, despite greater velocity SD than some other powders, it just groups tighter anyway. The proof is always in the pudding and not on the scale.