5.56 mm vs .223

[bkhann]

I am new to reloading 5.56/.223, in fact, I have been preping brass and have yet to reload a single round.

My question is do you separate 5.56 brass from .223 brass and treat them separately? The 5.56 does have a slightly smaller case capacity, and thus equal loads should result in the 5.56 having more power, but the cases are very similar.

Do you use different powder charges for the 2 different cases?

If you chrono your 5.56/.223 rounds? What kind of FPS are you generally looking for?

Thankyou for your help.

Bob

[billnourse]

With 5.56 brass you should reduce your loads a bit because of the reduced case capacity that you mentioned. You should be working up loads anyway so you will know when you are getting into pressures. In small capacity cases I go in .5 grain incriments. I would certainly be looking at different powder charges based on the brass. A max load for the .223 might be excessive in the 5.56. By the same token, a max load in the 5.56 could be a somewhat reduced load in the .223.

As far as velocities go, I would look for about 3500 to 3600 in 40 grain, 3200 to 3300 in a 55 grain, and 2900 to 3000 in the 62 - 68 grain. This info is based on what I am seeing out of my Rock River Predator Pursuit with a 20" bbl.

Bill

[jepp2]

That approach will keep you out of trouble. The attached file link shows that not all military brass "weighs" more. Normally thicker brass = less internal volume and weigh more.

The most accurate way is to determine the water volume of the case. Weigh a fired case, fill it with tempid (70 degrees water) and weigh it again. Subtract to get the water volume of the case. Now you have an accurate comparison.

Use the Excel file, 4'th down on this page:

http://www.ar15barrels.com/tech.shtml

[DoubleUp]

Actually reduced case capacity from thicker brass is more likely to be found in 7.62 (308).

Molon over on AR-15 did quite a bit of testing on various lots of military and commercial brass in 223/5.56. His findings were that Lake City (military) actually had more case capacity than Lapua. Others have had the same results.

A search should give you better info to make your own decision or at least run your own test.

Don't take anything on the web as absolute fact including my post. You're the one who is going to be pulling the trigger, not me.

[demigod]

If you chrono your 5.56/.223 rounds? What kind of FPS are you generally looking for?

Depends what you're after. I load for bulk practice. So I like something around 3000-3100 from a 20" AR barrel.

In my opinion trying to load to full house mil spec is silly, a waste of powder, and extra needless wear and tear on your gun. But to each his own.

With 5.56 brass you should reduce your loads a bit because of the reduced case capacity that you mentioned.

Completely WRONG. This myth will never die, I guess. As DoubleUp said that's a .308 issue. Mil brass in 5.56 usually has a slightly higher internal case capacity. I say the volume diff is negligible... unless you're making precision ammo... But you probably wouldn't be using mil brass for that.

[m&p45acp10+1]

From what I have been told. The only way to be ceartian is to water weigh them your self. I admit to being guilty of not doing so. I shoot a bolt action Savage in .223 Rem I sort by head stamp, and load on the low end anyway. (Note 99% of my brass is Federal due to the fact that guys leave tons of it when shooting thier AR's.)

[goodspeed(TPF)]

When reloading for fun (NOT max loads), I mix brass from all manufacturers that I have and 5.56mm or .223 matters not. -Goodspeed

[steve4102]

Completely WRONG. This myth will never die, I guess. As DoubleUp said that's a .308 issue. Mil brass in 5.56 usually has a slightly higher internal case capacity.

Correct! Sierra has it right as well. Go here and read what they say about case capacity in 223/5.56 brass. Scroll down to "Brass Preparation".
http://www.exteriorballistics.com/re...sgunreload.cfm

You can also go here see that 5.56 brass has More case capacity that 223 brass.
http://www.6mmbr.com/223rem.html

[demigod]

When reloading for fun (NOT max loads), I mix brass from all manufacturers that I have and 5.56mm or .223 matters not. -Goodspeed

Same here. Once I get the crimp off an trim (if necessary) it's all the same to me.

[rjrivero]

Another vote for "treat them all the same."

As long as you aren't on the ragged edge, load em up and shoot em!

[HiBC]

Depends on what you are trying to achieve.
If the primary goal is going bang and putting another round in the chamber,if you want to reload generic "ammo" to have fun blasting with,it does not matter a whole lot,just give yourself a little more safety margin by not pushing max
One point you should be aware of,wathch your case length.Read about it in your loading manual.The short story,if the cases are too long,they will run into the chamber.Then they are not free to open and release the bullet.This can raise pressure.
If you would like to take a step up in handloading,sort all your cases into different batches.Keep a notebook.Package and use them in a way that you can make observations and learn some things on your own.Maybe brand x gets loose primer pockets aftre 4 loadings,and brand y gives you 6.Which kind will you order 1000 of in the future?Or you may find 1/2 moa better accuraccy with brand x.
Minimize and isolate variations ,and you will learn more and make a better product.

[demigod]

I pretty much know how every flavor of brass behaves. I generally toss brass into the recycle bucket after two reloads since my brass collection generally grows quicker than I can wear it out.

Sometimes I like exploring different brands of brass more than I like shooting the ammo up.

[mehavey]

Completely WRONG. This myth will never die, I guess. As DoubleUp said that's a .308 issue.

Just for grins I went down into the basement and weighed the water volume of my 308/Winchester brass vs my 7.62/LC`81 Match brass. Surprisingly it came out identical: 55.6gr.

Bottom Line:
- Don't assume.
- Find out

[flashhole]

My experience has been that the mil stuff does have less case capacity. My use for the mil brass is a bit different. I seek it out when re-forming 223 (5.56) to 221 Fireball becasue the added thickness in the web lets me turn the necks to a tight fit in my guns chamber. The load I use for the Fireball gives better case fill with mil brass compared to factory brass.

[HiBC]

demigod,cool,you have plenty of experience.My comments were to the OP,who is just about to load his first round.
In your opinion,in the long run,would he be better off separating his brass,loading for consistency,keeping a log,making observations,or just mixing it up and making generic go bang loads?
BTW,long ago,I had some pretty interesting processes of making go bang loads!I did not use my sights much then.
Now,I prefer seeing my groups shrink,finding what my rifle likes.

[DoubleUp]

Mehavey, do you think you would get the same result if you used regular 7.62 military surplus rather than the LC Match? Thanks and appreciate your informative posts.

[bkhann]

Thanks guys, for all of your input. Here is what I plan to initially do:

* Separate .223 from 5.56 brass and load separately
* Control cartridge lengths to 1.74” to 1.76” (most will be closer to 1.75”)
* Load 55 gr bullets w/ Varget Powder at 80% of published max, working
up to 3200 fps
* My goal is to load consistent good shooting ammo

I bought 1000 rounds of Lake City 5.56 FMJ XMF-193 F ammo. I will start with this in my new RRA Operator-2 AR-15 (which is on order and should arrive sometime mid February). In the spring I will chrono the Lake City ammo for a reference point, and then start developing my own loaded ammo.

Again, thanks for your help!

[m&p45acp10+1]

Demigod you have a point about the growing brass collection. I have a steady supply of .223 brass. Especialy Federal. Guys show up with ARs and Walmart bags with several of the 100 round boxes of bulk Federal. They leave more brass than I even bother with picking up.
I also seem to find a couple of handfuls of LC brass ever trip. I just put it to the side, and will work up some loads using it at a later time.

[DoubleUp]

Bkhann, if you start at 80% of published max for Varget you may be too low to cycle the AR. Hodgdon shows max of 27.5 with 55g bullets. Even if you consider 27 as max and start at 80% you will only be at 21.6g which could be underpressure. Hodgdon shows their starting load at 25.5g with 55.

Sierra lists 25.1g Varget as starting load with AR-15 and 27.2g as max for all their 55's. Just saying!

[billnourse]

bkhann,

I have found that Benchmark will give you near exactly the same performance, speed and accuracy, with 1 or1 1/2 grain less charge than Varget. Not much, but every little savings helps.

With 25.3 grains of Benchmark and 55 grain Nosler BT's I am getting 3200 to 3300 FSP and consistant 1/2" 5 shot groups. This is near max and should be approached as such.

Bill

[milo-2]

bkhaan,
I sure hope you proceed with caution. I noticed in your last post you stated;

[Control cartridge lengths to 1.74” to 1.76” (most will be closer to 1.75”)]
[Load 55 gr bullets w/ Varget Powder at 80% of published max, working
up to 3200 fps]

Max case length for .223 is "1.760", trim length is "1.750", you can trim your cases shorter, but running case length of "1.775" is not good. First, they probably won't stretch to that length on first firing. Second, they might not feed right, too far in the throat, third,you might end up seating your bullets too far in the case. The last two can result in pressure, not where you want to be.
You really need to follow a load manual regarding min and max loads, not enough powder could result in a bullet not exiting your barrel, not a good thing. And not all 55gr bullets are alike, a 55gr Nos BT, and a 55gr Horndady Vmax will have varying charge wieghts of the same powder.

At least with the RRA platform, you will be getting a 5.56-.223 combo barrel, because the difference between the two is in the chamber of the gun, not the ammo. I wouldn't recommend handing a buddy a few of those XMF-193's to torch off in his bolt action gun, you might not be pleased with the results.

Finally, good luck getting 3200fps out of your 16" carbine.
Shoot safe

[Unclenick]

Never let the case go over published maximum length. The neck profile in the chamber usually has a little leeway, but not a lot. If the case gets long enough to touch the end of the neck profile in the chamber, either on loading or during neck stretching upon firing, it can jam into the freebore and prevent the bullet being released at normal start pressure. That can raise peak pressure dangerously.

It think Bkhann meant "case" when he said "cartridge", but it never hurts to make sure there is no confusion.


Bkhann,

I find Varget is a little slow for 55 grain bullets. It's better with 65 grains and up. I prefer Reloader 10X, which gives more velocity with about 10% lower charge weight for the 55 grain bullets in .223. The heavily compressed load of Varget that Hodgdon lists at 3384 fps is for a 24" barrel. QuickLOAD says that will become about 3080 fps from a 16" barrel. That's more in line with what your velocity objective should be.

DoubleUp is correct that 80% of published loads is usually too low. QuickLOAD shows 10% below published maximum will drop pressure about 25% in the .223 with a standard case volume. That's enough. If you get too little powder it doesn't burn well and you can get some funny spike behavior and lots of extra fouling because the burn is poor. Unlike .308, military and commercial case volumes are not very different in .223/5.56, so the old 10% rule is fine to use.

I would avoid softer primers like Federal and Winchester in the mouse gun. The CCI's are harder, and the CCI #41, specifically is made for the floating firing pin gas gun. I would use that if you can get it, just for the extra safety margin against slam fires.

[demigod]

demigod,cool,you have plenty of experience.My comments were to the OP,who is just about to load his first round.
In your opinion,in the long run,would he be better off separating his brass,loading for consistency,keeping a log,making observations,or just mixing it up and making generic go bang loads?
BTW,long ago,I had some pretty interesting processes of making go bang loads!I did not use my sights much then.
Now,I prefer seeing my groups shrink,finding what my rifle likes.

I'm all about puting the bullet where I want it to go. But there's a balance. I mean.... you can check every cartridge for bullet runout and go crazy checking every little thing.

But at some point, you have to figure out how much effort you want to put in, and what you need to get out of it.

[bkhann]

I did mean case length (not cartridge length).

I have about 1800 cases prep'd and ready to go. My new RRA Operator 2 will not be in until mid February, so there is pleanty of time to decide on the best load. I did buy 1 lb of Varget and 2000 55gr FMJ bullets, so come spring I will look at and chrono several loads. The goal is to have a very consistant and accurate everyday load for range and possible 3 gun competition use.

This stuff all takes time. I appreciate the knowledge and experiance that you guys bring to the table.

Thank you

Bob Hann

[jake556]

I don't separate them haven't notice any differences with same load.