Reloading 223 vs 5.56mm question

2398 Views 65 Replies 25 Participants Last post by Falt, 9 d ago

crosswater

Discussion Starter · 2 mo ago

For those of you who reload 223 Remington and 5.56mm

Can you use the same reloading data for 223 cases and 5.56 cases?

Thanks

41 - 60 of 66 Posts

Grizzman

· #41 · 2 mo ago

As Kent stated, it's not always possible to make absolute statements about brass. It's best to segregate brass by type and work up loads specifically for each.

If you've got a bunch of Winchester commercial, load it with 69 gr RMR HPBTs. All the Lapua brass you've got would work well with 77 gr SMKs. Any Noslers can be used for 62 grain Gold Dots for self defense. All the Lake City you've got would be suitable for 62 grain Hornady HPBT.

This way there are no doubts about the capacity of each case, and it makes it really easy to identify a 62 gr HPBT cartridge from a 69 gr HPBT load from a 77 gr HPBT,

Unless you're doing something unusual.....and it seems like you're a new handloader, so don't start out doing the unusual.....there's no need to start load development at the minimum powder charge (unless you're looking for a slow, low recoil load). Starting at 10-15% below maximum (depending on how closely your components match the book) is reasonable. If changing an important component, you can drop it by around 5% and start working up again.

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longarm

· #42 · 2 mo ago

Or just trade it off and get a BB gun.

Reactions: 1

Real McCoy

· #43 · 2 mo ago

The OP commented that the gun will shoot both.
Okay, back on topic.

Load .223 cases using .223 load data and components.
Load 5.56 cases using 5.56 load data and components.
Carefully mark all boxes or bags of each in case you or another hobbyist wants to later shoot a .223 only rifle that is not compatible with the 5.56 ammo.

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Falt

· #44 · 2 mo ago

The SAAMI 223 vs 5.56 comparison never seem to add up.

One thing that come up often when some web site or youtube video wants to bring order to this is that SAAMI, EPVAT and CIP measure pressure different ways and that it skews the SAAMI readings.

If the information I have found is correct the SAAMI measurement is made at the outside surface of the case, the CIP measure at a drilled hole in the case and EPVAT (NATO) measure in front of the case.

But comparing SAAMI 308 and 7.62 show that they are almost the same.

Comparing load data for 5.56 and CIP 223 is also very similar, while SAAMI 223 load data is significantly lower. Running the load data in simulation software usually show around 500 bar lower pressure than for CIP or 5.56 load data.

It could be that the industry has standardized on the SAAMI 223 pressure even if they know that the pressure measurement skew the readings.

If it's common to cut 223 minimum dimension match chambers in the US it could also be a factor.

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pete177

· #45 · 2 mo ago

Don't forget to adjust for temperature, humidity, atmospheric pressure, powder lot number, bullet lot number, elevation (pressure altitude), barrel length, rifle twist, stages of the moon and Margaret Thatcher's menstrual cycle. Be advised, aforementioned list is not all inclusive and in no way constitutes advise for the manufacture of ammunition. Have a nice day.

USMM guy

· #46 · 2 mo ago

Just to get it out there, as stated earlier Hornady lists separate "service rifle" data specifically for 5.56 NATO. I had said also that I thought that Lyman did as well. I was wrong about that but I did note that Nosler lists separate "service rifle" data for 5.56 NATO at least in their seventh edition manual they do.

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crosswater

Discussion Starter · #47 · 2 mo ago

Sierra bullets told me the only powder manufacturer they knew of that split 223/5.56 data was Western Powders Ramshot (owned by Hodgdon now)

Nobody else's powders were split out.

This was just for powder manufacturers.

Snapdragon

· #48 · 2 mo ago

crosswater said:
The minimum load listed?

I would not start below the minimum load listed. Some powders do not take kindly to very light charges. The 10% reduction, unless I am greatly mistaken, is from the max listed load. Some people start there instead of at the minimum suggested charge.

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CFIdentification

· #49 · 2 mo ago

crosswater said:
For those of you who reload 223 Remington and 5.56mm

Can you use the same reloading data for 223 cases and 5.56 cases?

Thanks

ABSOLUTELY NOT! .223 is a commercial (SAAMI) spec cartridge, the 5.56 is a military cartridge without a SAAMI load recipe. 5.56 casing is thicker than .223, and the pressure differential between the two is higher, to the side of the 5.56. There are other differences which get technical, these are but the basics.

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Pike_Bishop

· #50 · 2 mo ago (Edited)

Interchangeable, internet fallacy or wives' tale
Load to manual specs and go shooting.
I have reloaded thousands of mixed brass, military and commercial over 40 years shooting Mini14's, AR15's and bolt actions

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crosswater

Discussion Starter · #51 · 2 mo ago

Pike_Bishop said:
Interchangeable, internet fallacy or wives' tale
Load to manual specs and go shooting.
I have reloaded thousands of mixed brass, military and commercial over 40 years shooting Mini14's, AR15's and bolt actions

Thanks

Vic Mackey

· #52 · 12 d ago

No you can’t. The brass is different. 5.56 is stronger. As said above if not loading to the max shouldn’t make a difference. In my experience of loading many 1000’s of 5.56 rounds with either 25.0 grns of H335 or 24.5 grns of TAC it hasn’t made a bit of difference since they are not super hot loads. Both are very std loads used by many people and ball powders work best imo with SRM primers. Just my experience please start low and work those loads up to be safe in your rifles. My rifles are all chambered in 5.56 and are different than yours. Good luck

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longarm

· #53 · 11 d ago

crosswater said:
For those of you who reload 223 Remington and 5.56mm

Can you use the same reloading data for 223 cases and 5.56 cases?

Thanks

I think it's about time to lock this thread..

5.56nato and 223Rem are externally Identical. Full stop.
Any rifle labeled "5.56nato" (or 5.56x45) can fire 223Rem, (and in the army folks would buy and carry a box, yes).
Any rifle labeled "223Rem" should not be firing milspec 5.56 at ALL! The pressure rating is HIGHER for the military, (and they measure from a different POINT on the case).
Any reloads of EITHER case (223Rem or 5.56) with low, medium or high-end 223Rem load data will work FINE in rifles labeled either way - and including 223Wylde.

SO, yes: if you follow only 223 recipes, the brass will work the SAME and rifles labeled ANY of the above can use them.

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Kent Dorfman

· #54 · 11 d ago

Vic Mackey said:
No you can’t. The brass is different. 5.56 is stronger.

Source for above?

Onibaba

· #55 · 11 d ago (Edited)

Two cents added...

Outside dimensions are identical. Inside dimension are identical (for 223 / 556).

However, Internal dimensions will vary from manufacturer to manufacturer regardless of commercial or military made.

The rumor about 223 versus 556 case tolerances are not the same as the differences between 308 versus 762.

In said case, you must reduce the load 10% or risk a case rupture in 308.

The issue of chamber pressure is a different topic.

But the specs and tolerances between 223 and 556 cases are the same.

I accidentally applied the military / commercial internal specs of 308 / 762 toward 223 / 556 thinking there was a common difference and was schooled with data showing there was no such correlation.

If you are concerned about it, then the best practice is to separate your brass by military versus commercial and by manufacturer. Then work your loads without mixing brass.

However, this is usually too much time wasted for the average auto loading rifle shooter shooting 223 / 556...

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snuby642

· #56 · 11 d ago (Edited)

I separate headstamps and work up a load for each. Range brass gets separated and when a decent size run can be made I do it.

Pouring out loads of mixed brass just because it is for an ar leads to minute of DONKEY accuracy and may as well be used for mag dumps.

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crosswater

Discussion Starter · #57 · 10 d ago (Edited)

Good stuff

Only Tac powder seems to have 5.56 data

So data should be brass dependent on manufacturer?

Different data for different brand brass

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snuby642

· #58 · 10 d ago (Edited)

There is going to be a volumetric difference in brass.

So if you seat your bullet exactly the same and put exactly the same powder in different manufacturers brass they will not necessarily be the same velocity due to that space difference.

By starting 10% below powder manufacturers or reliable reloading book max you can be safe working up to the sweet spot for that gun.

Max load normally allways sucks in mine. It's common for me to find loads at 95-98% max recommended.

People shooting in ELR / other competition regularly exceed book to gain performance .

They run a load up till primers flatten or pop and I have as well.

I now concentrate on watching my development groups and can tell when the load is at my max for me.

The groups will be scattered, vertical or horizontal stringing, then one or two 0.3 grain incraments will group .
Invariably the next group will open noticeably the next will scatter.

My advise is pull down every thing past that and don't bother poping primers.

You can go back and bracket the best load or split it if you have two, and do 0.1g incraments then a seating test if you want.

You can get to some nice sub moa loads with that. If you are going to ELR you should throw a chrono in the mix.

If you are a good shot you can get through some of the preliminary tests with 3 shots each to conserve time or if using expensive bullets.

If three won't group within reason five won't look better.

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longarm

· #59 · 10 d ago

W/o a chrono, the best solution is to pick the bullet and powder, start low and ladder-up. I like to ladder oddball as my digiscales can always be plus/minus one (on A) and two (on B). And, for rifle yer steps can be slightly wider if you like.

The "winner" is whoever fires the best group. Game over. Done. No debate.

THAT settles that bullet and powder.

In reality, others will now obsess about seating-depth/OAL, "distance off the lands" and a variety of "I really don't give a damn stfu!"

Generally, I move on to testing another bullet and/or powder in the same way <shrug>

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kilowatt3

· #60 · 10 d ago

longarm said:
I think it's about time to lock this thread..

5.56nato and 223Rem are externally Identical. Full stop.

Any rifle labeled "5.56nato" (or 5.56x45) can fire 223Rem, (and in the army folks would buy and carry a box, yes).

Any rifle labeled "223Rem" should not be firing milspec 5.56 at ALL! The pressure rating is HIGHER for the military, (and they measure from a different POINT on the case).

Any reloads of EITHER case (223Rem or 5.56) with low, medium or high-end 223Rem load data will work FINE in rifles labeled either way - and including 223Wylde.

SO, yes: if you follow only 223 recipes, the brass will work the SAME and rifles labeled ANY of the above can use them.

There is at least one notable exception to your #3 above - With the exception of the Target Models, all .223 Ruger Mini-14's are designed for (and safe with) mil-spec 5.56 NATO.

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