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

21 - 40 of 66 Posts

USMM guy

· #21 · 2 mo ago

crosswater said:
I wish more reloading manuals would split out 223 vs 5.56 spec data

My Hornady manual does, referring to 5.56 as "service rifle" loads. I am pretty sure that my Lyman manual does two. I will check them later. Showing a little prudence in what you load in terms of powder and firearm. This will usually keep you in good safe territory as there is not a huge difference between the rounds. I shot NATO spec 5.56 ammo out of some .223 chambered rifles for a long time before I even knew there was a difference with no issues.

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Kent Dorfman

· #22 · 2 mo ago

crosswater said:
I wish more reloading manuals would split out 223 vs 5.56 spec data

Dont overthink it. If you plan on starting load development at the max listed data you might have an issue.

If you start low-ish and work up you will be fine.

Reactions: 2

Grizzman

· #23 · 2 mo ago

crosswater said:
So it doesn't matter what cartridge case I use?

Both can be loaded to 5.56 velocities?

You are correct. It is best to use a likely stronger 5.56 case, but it is certainly possible to reach 5.56 pressure levels with 223 Remington brass.

Reactions: 1

pete177

· #24 · 2 mo ago

I'm confused. Is that deer gonna notice a 200 or 400 fps drop in velocity, from 3200 to 2800? Maybe the trim to length is a hair different but i trim and shoot .223 in my 5.56 m4 all day long. Plinking, 3 gun or something like that? Who cares? I dont even work up loads. Who's got time for that? I load mid range and press on. My 223/5.56 chrono at 2900 or so with a 55gr. Thats all i need to know. I re use my brass. Do I really want to max it out every time?

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Falt

· #25 · 2 mo ago

CIP pressures for 223 is quite a bit higher than the SAAMI pressures for 223. I can only guess that most European 223 ammunition is loaded to SAAMI pressures as I think that it could make it hard to sell it in the US otherwise.

But the specification is still 3800Bar for SAAMI and 4300BAR for CIP.

To complicate it further European 223 brass seem thicker than US 223 brass. This causes problems when forming 300BLK brass from 223 brass. The body of the European brass makes the material in the neck of the 300 brass too thick.

I usually ignore US 223 data and go for the 5.56 data in your loading manuals.

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4barrel

· #26 · 2 mo ago (Edited)

Remove the crimp if needed. I've been shooting 223 before Scarch started selling 1000 L.C. brass cleaned and resized and crimp removed and 55 grain bullets combo for $65 delivered from Shotgun News.

Font Parallel Paper Paper product Document

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snuby642

· #27 · 2 mo ago (Edited)

2

pete177 said:
I'm confused. Is that deer gonna notice a 200 or 400 fps drop in velocity, from 3200 to 2800? Maybe the trim to length is a hair different but i trim and shoot .223 in my 5.56 m4 all day long. Plinking, 3 gun or something like that? Who cares? I dont even work up loads. Who's got time for that? I load mid range and press on. My 223/5.56 chrono at 2900 or so with a 55gr. Thats all i need to know. I re use my brass. Do I really want to max it out every time?

Wow.

Orange Textile Font Art Material property

Orange Textile Font Art Material property

Orange Yellow Line Font Art

No load workup

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Snapdragon

· #28 · 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

Yes.

You might want to do what you should do with any other chambering and work up a load for each different headstamp if you want to push the upper pressure limits or want maximum consistency. I do not generally push the limits and do not worry whether the case is 223 or 5.56.

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Kent Dorfman

· #29 · 2 mo ago

https://winchesterle.com/Blog/2010/10/223-Rem-vs-556mm

https://www.accurateshooter.com/cartridge-guides/223rem/

223 -vs- 5.56: FACTS and MYTHS – Ultimate Reloader

ultimatereloader.com

Reactions: 1

crosswater

Discussion Starter · #30 · 2 mo ago

Would just like to try Sierra match king bullets at velocities they will fragment

With 5.56 brass and could also use the data for 223 brass

mercman1972

· #31 · 2 mo ago

crosswater said:
The gun can shoot both

I thought 5.56 vs 223 was always centered around the cartridge case and any data labled "223 Remington" was only for use in 223 cases

I at one time had friend that didn't weigh his powder charges. He would use the cartridge case as a powder scoop and fill it to the case mouth and compression seat the bullet. He'd been doing that for years. Gave me the shudders, but he'd shot thousands of rounds that way.

Me, I'm and Virgo and too anal for that method.

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longarm

· #32 · 2 mo ago

Kent Dorfman said:
https://winchesterle.com/Blog/2010/10/223-Rem-vs-556mm

https://www.accurateshooter.com/cartridge-guides/223rem/

223 -vs- 5.56: FACTS and MYTHS – Ultimate Reloader

ultimatereloader.com

I'll buy that story.

longarm

· #33 · 2 mo ago

mercman1972 said:
I at one time had friend that didn't weigh his powder charges. He would use the cartridge case as a powder scoop and fill it to the case mouth and compression seat the bullet. He'd been doing that for years. Gave me the shudders, but he'd shot thousands of rounds that way.

Me, I'm and Virgo and too anal for that method.

Nuttin' wrong with Volumetrics. Dumps use the same idea. I'd guess yer friend simply had been using the same load since he got off Noah's Ark.

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crosswater

Discussion Starter · #34 · 2 mo ago

The 5.56 cartridge case may have thicker walls, and a thicker head, for extra strength. This better contains the higher chamber pressure. However, a thicker case reduces powder capacity, which is of concern to the reloader.

mdell49

· #35 · 2 mo ago

crosswater said:
But what if all you have is 5.56 brass

Reduce by 10% of listed load and work up. You won't blow up the gun

Reactions: 1

Snapdragon

· #36 · 2 mo ago

mercman1972 said:
I at one time had friend that didn't weigh his powder charges. He would use the cartridge case as a powder scoop and fill it to the case mouth and compression seat the bullet. He'd been doing that for years. Gave me the shudders, but he'd shot thousands of rounds that way.

Me, I'm and Virgo and too anal for that method.

The success of that method depends a lot on what powder he uses.

Reactions: 1

crosswater

Discussion Starter · #37 · 2 mo ago

mdell49 said:
Reduce by 10% of listed load and work up. You won't blow up the gun

The minimum load listed?

snuby642

· #38 · 2 mo ago

I have several ar's.
Carbine and sbr length.

But this with out a doubt is my favorite.

Trigger Wood Air gun Gun barrel Rectangle

Didn't have time for a fancy staged shot.

I have developed 2 sub moa loads for it.
52g speer (3/8 moa best)
55g fmj (.50 - .60 best)

But you have to put some effort into it.

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Kent Dorfman

· #39 · 2 mo ago

crosswater said:
The 5.56 cartridge case may have thicker walls, and a thicker head, for extra strength. This better contains the higher chamber pressure. However, a thicker case reduces powder capacity, which is of concern to the reloader.

That is one of those "depends on" things. Notice the above says "may have."

I have some Lapua 223 brass that is a lot heavier than any LC 5.56 brass but I also have some IMI stuff that weighs less.

Just work up a load and go from there.

I just pick a nice mellow load that is accurate and cycles the rifle. Then load up a bunch and go to the range.

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mdell49

· #40 · 2 mo ago

crosswater said:
The minimum load listed?

That would be the safest approach, Who knows that may be the most accurate load you try. I'm an old guy and put more emphasis on accuracy over velocity. So although you may use a bit more powder and primers in loads development in this manner you will find the most accurate combination and do so safely. Good Luck

Reactions: 1

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