Question about the difference between 5.56 &.223 CASES

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Joshboyfutre

Joshboyfutre

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Im still a little confused about the difference between 5.56 cases and .223 cases when it comes to reloading. I have a good load using 5.56 cases, its a 55g FMJ on 26g of varget ( barely compressed). The exact same load in .223 wasn't grouped as well. I reloaded both together and wanted to see the difference. Now I want to get the same accuracy out of .223 brass. I've heard that u want to back 5.56 off approx. 1.0g. So in theory (which is never right!) if I take the 5.56 load and add 1.0g I should get the same results... Right? So I'm gonna try loading up my .223 brass with 27g of varget and that should put me where I want to be... Hopefully
 
In theory there is no difference between 5.56 and .223 cases. However, different brands of cases have different wall thicknesses and capacities. Also, the loading specifications for 5.56 and .223 chambers are different, as are the chambers themselves.

Try sorting your .223 cases by brand and see if that helps. It is also the case that some manufacturers of brass are more uniform in their dimensions and those cases tend to be more accurate. Lake City 5.56 is very high quality.

Hodgdon's web site lists a max of 27.5 grains of Varget for a 55 grain soft point in .223 Rem. Since you are changing brass manufacturer, work up again as you are near max.
 
Like said 5.56 and 223R are one in the same when it comes to the brass. Only the marking on the base is different. The difference is in the chamber, with 5.56 having more free bore. 5.56 ammo is higher pressure with higher velocities.

All brass mfg have a slightly different case volume. I separate all my brass by mfg and year. I have found that different year LC brass requires a slight OAL change to get the same accuracy. What this does is change the pressure in case, fine tune them to match. Not by much but it makes a huge difference with some.

Setup and measure case volume of your cases that work good then compare it to the one that is not. A crony will help out too in showing the differences.

I would workup a new load for the different brass. Part of the enjoyment of hand loading.
 
Your plan to raise powder charges up one grain for commercial brass isn't safe. Some commercial cases weigh more and have less internal volume than does some military cases. Your one grain increase may be over pressure. I find very little on no accuracy increases between Lake City, Remington, or Winchester brass. Rem and LC are very close in weight. Lake City is actually lighter than Federal brass and some other commercial cases. Here's a good article and it has a chart with some case weight and internal volumes. Don't jump up one grain or you might have problems? If you want a maximum accuracy load, weigh and sort your brass by brand and weight.
http://www.6mmbr.com/223rem.HTML
 
In raising it I'm still within recommended max load. The load I'm adding to is an accurate load in my rifle... Not a max load. Thank u for the heads up though cause I can see how u thought I was about to do something unsafe. Good looking out man.
 
I have heard it said that case thickness is more in 5.56 and less in .223 because 5.56 is expected to handle higher pressure, basically the same as with 7.62×51 and .308. Has anyone else ever heard that? I figured thats what the accuracy difference was from, thats the whole reason I loaded two lots. One 5.56 and one .223. So once Ive trimmed the brass can I just throw it all together?
 
I have heard it, but it simply isn't true.

I have LC 5.56 brass that is thinner, lighter, with more capacity the commercial Remington .223 brass I also have.

My advice is, size it, trim it, and weigh it.

If it weighs the same, it is the same.

Further, if accuracy is your goal, you can't do it with mixed head stamp brass.

Sort it by head stamp, and load it in like batches of all the same brass.

rc
 
Accuracy isn't a big deal for me on this particular rifle, its an AR with iron sights. I was more or less experimenting to see the difference between 5.56 and .223 if there was one. Just something to do. I did end up getting some really good groups though. Approx. 2 moa w iron sight is good enough for me with a 1:9 twist. Wouldn't mind getting a bolt-action .223 and really going after it tho. Thanks for the advice guys.
 
I somehow must have misread your first post then.

You said:
Now I want to get the same accuracy out of .223 brass.
Click to expand...

I took that to mean you had some interest in accuracy?

But never mind.
The same advice applies.

Sort them by head stamp, load them in those batches.

rc
 
Would have liked to, but in theory its the same load is what I was told. It was literaly loaded together with the 5.56, same charge,c.o.a.l., all that. Did them in sets of ten. If the cases are the same after trimming then...
 
If I'm loading 5.56/223 plinking rounds then I will mix brass and not worry about it, but if I'm loading 223 LRP rounds for my bolt action I use only Lapua brass.
 
I have a good load using 5.56 cases, its a 55g FMJ on 26g of varget ( barely compressed). The exact same load in .223 wasn't grouped as well. I reloaded both together and wanted to see the difference. Now I want to get the same accuracy out of .223 brass.
Click to expand...
Whether the case is marked 5.56 or .223 makes no difference. The case capacity does. You can sort by headstamp, weigh cases, or check to see how much H2O they each hold. If they are the same headstamp and same lot #, it all depends on the quality of the brass, but it should be consistent enough for your purposes. The next easiest way is to weigh the cases. If the average case weight of the batch of ".223" cases is very close to the average of the "5.56" cases, the same load should work. Heavier? Might need to drop .1 Gr or so. Lighter? Might have to bump it up .1 Gr or so, or maybe not.

Make sense?
 
Yeah that does make sense. I was thinking the 556 and took you three were different but it's actually just a variation in cases in general that I think I was dealing with
 
So far I've found that mixed brass in my .223 bolt gun hasn't made that big of a difference in accuracy. It's been relatively easy to find accurate loads for multiple bullets.....as long as the common denominator is Varget.
 
I have a feeling your accuracy variation has more to do with the different brand of brass than it being 5.56 or .223. Aside from the capacity differences spoken about above you will also get different neck tension from different brands brass. It all counts.

Just a note, I have gotten better accuracy with a charge of 25.0gr Varget under a 55gr bullet than 26.0gr in several different brands of brass. Try 25.0gr and see if accuracy improves.
 
Yeah I think ur right, that seems to be the general concences. I wonder if maybe 5.56 cases are made to more strict specs than. 223 also. As the charge of varget goes, I have been working my way up from 25g, my Rifle is a 1:9 twist and I'm willing to bet u have a 1:7 twist. It's a Delton Sport, but hey I picked it up for $500 and thats the only thing I would change is the twist rate. For being a lower rung AR its actually been a really good rifle up to this point. Might have gotten a S&W M&P-15 if it had a dust cover and forward assist (the new ones do) being a combat veteran I know the importance of having them.
 
Joshboyfutre said:
Yeah I think ur right, that seems to be the general concences. I wonder if maybe 5.56 cases are made to more strict specs than. 223 also. As the charge of varget goes, I have been working my way up from 25g, my Rifle is a 1:9 twist and I'm willing to bet u have a 1:7 twist. It's a Delton Sport, but hey I picked it up for $500 and thats the only thing I would change is the twist rate. For being a lower rung AR its actually been a really good rifle up to this point. Might have gotten a S&W M&P-15 if it had a dust cover and forward assist (the new ones do) being a combat veteran I know the importance of having them.
Click to expand...
I will take that bet... Nope, not a 1:7 twist. My AR barrel is 1:9 twist and my Howa 1500 barrel is 1:12 twist.
 
Look at the details a little close you will see minor differences in specs. It seams every mfg has there own idea of what it should be. Some are very loose while others are tight. Most of the match grade chambers are on the tighter side.
 
Remember ..... not all cases are "built" the same way. Some have a great deal of time spent on making them uniform... FGMM v. Bulk brass.

How many times fired are the .223 cases v. 5.56...how much difference in neck tension is there between the two ?
Are either of the case necks "work hardened" ?

I have found that neck tension can have a big impact on accuracy.
 
Joshboy you are way over thinking this. Unless you are shooting very long range and are squeezing out the last nano second of accuracy, you will be fine loading a recommended (book) safe load. Separate your brass if you want if it makes you feel better, between commercial and military brass.

Keep in mind unless you switch between a 5.56 sizer (if they make such a thing) and a .223 sizer, all the brass will have the same outside dimensions. The military brass may have a thicker neck and base but that's about it. In that case stay away from max loads.

Reloading is supposed to be fun and can be relaxing along with the benefits of custom made ammo at a better price. JMHO.
kwg
 
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