5.56 become a .223?

[Moorvogi]

I'm sure this has been asked, but I'm not seeing a link at the moment. While I'm looking.. here's my question.

I'm aware that the EXTERNAL dimensions on a 5.56 are the same as .223 but the INTERNAL are different. When i shoot a 5.56 (out of a 5.56 barrel) all is well. When i then reload that brass using a .223 die... is it .223 or still 5.56?

I'm ASSUMING the brass stretches out the brass to reform the internal dimensions to that of .223 vice 5.56, but would rather not blow up my barrel or worse based on an assumption.

 

[teratos]

I'm sure this has been asked, but I'm not seeing a link at the moment. While I'm looking.. here's my question.

I'm aware that the EXTERNAL dimensions on a 5.56 are the same as .223 but the INTERNAL are different. When i shoot a 5.56 (out of a 5.56 barrel) all is well. When i then reload that brass using a .223 die... is it .223 or still 5.56?

I'm ASSUMING the brass stretches out the brass to reform the internal dimensions to that of .223 vice 5.56, but would rather not blow up my barrel or worse based on an assumption.

As long as you don't load to 5.56 pressures you should be fine using military brass for reloading in your .223.

 

[outrider58]

As long as you don't load to 5.56 pressures you should be fine using military brass for reloading in your .223.

What he said ^^^

The thing about military brass is, it is thicker which means it has a smaller internal volume. That boosts internal pressures compared to that of a .223. when loading military brass, start low and work up keeping an eye out for over pressure. Look and compare load recommendations between the two and you'll notice 5.56 are generally loaded lighter given the same powder and bullet combination .

 

[atblis]

The whole military 5.56 having less capacity than 223 is a myth. It's been measured. The most common military 5.56 case, Lake City, happens to have one of the higher capacities. I suspect this myth comes from the differences between 308 and 7.62x51 (which are usually different).

I'm aware that the EXTERNAL dimensions on a 5.56 are the same as .223 but the INTERNAL are different. When i shoot a 5.56 (out of a 5.56 barrel) all is well. When i then reload that brass using a .223 die... is it .223 or still 5.56?

No. There are no differences between 223 cases and 5.56 cases externally or internally. That's why there are no 5.56 dies. Brass from brand to brand varies, but that has almost nothing to do with being 5.56 versus 223. In fact, some of the least capacious cases are actually commercial 223.

This whole thing is really a problem if you have something such as a Krieger AR barrel with their tight 223 chamber. There are some nice web write ups with pressure testing. I'll see if I can find them.

 

[outrider58]

Not so fast...

 

[DaemonAssassin]

Oh boy...

556 does have a thicker case wall, but when you use a FL 223 resizing doe, you are not forming the inside of the case, so there is no actual change to the internal dimensions of the case. While 223 and 556 are theoretically the same, you just have to reduce your powder charge by 10% and slowly work your way up from there, while looking for signs of over pressure.

 

[dreadpirate]

Thanks for that you tube video - I was having this discussion with a guy at work and am sending the You Tube link to him as it explains things much better than I did.

 

[atblis]

I wouldn't consider that video all that informative. He needs to compare more cases.

Scroll down a little bit, there's a case capacity comparison. Lake City comes out on top for the highest capacity.
http://www.6mmbr.com/223Rem.html

My own testing that I've been meaning to revisit. I do have a really spiffy digital scale now with data logging, so maybe soon.
http://www.pirate4x4.com/forum/outd...22554-223-v-5-56x45-case-capacity-survey.html

Lake City consistently has one of the higher capacities. As far as I can tell, it always has. 1973 was the oldest case I had on hand. If external dimensions are the same between the cases, that has to mean that the internal capacities of the higher capacity cases are larger due to thinner case walls. You can find examples of each that are at one extreme or the other. If I had to pick one or the other as being thinner to make a generalization, based on my measurements, I'd actually say commercial is thicker with less capacity.

 

[DaemonAssassin]

I wouldn't consider that video all that informative. He needs to compare more cases.

Scroll down a little bit, there's a case capacity comparison. Lake City comes out on top for the highest capacity.
http://www.6mmbr.com/223Rem.html

My own testing that I've been meaning to revisit. I do have a really spiffy digital scale now with data logging, so maybe soon.
http://www.pirate4x4.com/forum/outd...22554-223-v-5-56x45-case-capacity-survey.html

Lake City consistently has one of the higher capacities. As far as I can tell, it always has. 1973 was the oldest case I had on hand. If external dimensions are the same between the cases, that has to mean that the internal capacities of the higher capacity cases are larger due to thinner case walls. You can find examples of each that are at one extreme or the other. If I had to pick one or the other as being thinner to make a generalization, based on my measurements, I'd actually say commercial is thicker with less capacity.

Military ammo uses a different powder to achieve the same velocity as 223, while the 556 has less volume inside the case.

 

[Kagetsu]

If I could cut to a basic question I'd like to explore. Can 5.56 or 223, be reloaded to 5.56 ratings with available powder?

 

[DaemonAssassin]

If I could cut to a basic question I'd like to explore. Can 5.56 or 223, be reloaded to 5.56 ratings with available powder?

556 with the proper powder can be loaded to factory 556 specs. 223 will suffer over pressure with that same powder, because you will be putting more powder in, due to the internal dimensions of the case. That will also cause serious issues, like case head separation, blown primers, kaboom, and the list goes on.

If you were to use the same powder charge as 556, you would see a velocity drop, due to the unused space in the case.

 

[Biggfoot44]

Back at Post #10 & Basic Questions -

That actually addresses two, maybe 2.5 , seperate questions.

There is .223 vs 5.56 in regards to pressure.
There is .223 vs 5.56 in regards to velocity.
There is large degree of congrueity of these two, but there can various results depending on specific powder used in each.

Not so much with conventional construction bullets up to 55gr or so, but with heavier/ longer bullets, differences in throat and leade dimentions will make a big difference.

As noted above, internal case capacity varies brand to brand, even lot to lot. The sterotype is .mil cases having thicker walls / less internal capacity. As noted above thicker civillian cases overlap with thinner .mil cases. For specifics, measure capacity and/ weigh the cases in question.

I don't if this will answer the OP'S questions, but I'll put forth a few statements :

1. 223 brass can be handloaded to provide 5.56 velocities within 5.56 pressures ( for use in firearms suitable for 5.56 pressures.

2. 5.56 brass can be handloaded to provide .223 velocities with .223 SAAMI pressures.

3. Powder charges may require tailoring depending on the internal capacities of the specific cases. This is a factor of specific lot of cases, and not catagoric of mil vs civillian, and there is variation within each catagory.

 

[molonlabe]

In addition. ( all my ARs have wydle chambers. Marked .223 and 5.56
http://www.americanweaponscomponent...the-caliber-confusion-223-wylde-vs-5-56-nato/

 

[outrider58]

Back at Post #10 & Basic Questions -

That actually addresses two, maybe 2.5 , seperate questions.

There is .223 vs 5.56 in regards to pressure.
There is .223 vs 5.56 in regards to velocity.
There is large degree of congrueity of these two, but there can various results depending on specific powder used in each.

Not so much with conventional construction bullets up to 55gr or so, but with heavier/ longer bullets, differences in throat and leade dimentions will make a big difference.

As noted above, internal case capacity varies brand to brand, even lot to lot. The sterotype is .mil cases having thicker walls / less internal capacity. As noted above thicker civillian cases overlap with thinner .mil cases. For specifics, measure capacity and/ weigh the cases in question.

I don't if this will answer the OP'S questions, but I'll put forth a few statements :

1. 223 brass can be handloaded to provide 5.56 velocities within 5.56 pressures ( for use in firearms suitable for 5.56 pressures.

2. 5.56 brass can be handloaded to provide .223 velocities with .223 SAAMI pressures.

3. Powder charges may require tailoring depending on the internal capacities of the specific cases. This is a factor of specific lot of cases, and not catagoric of mil vs civillian, and there is variation within each catagory.

This is probably the best answer here for the OP.^^^

Though I stand by my first post here, I would change the beginning by starting with "Generally speaking," in place of "The thing about"

 

[atblis]

I suggest you review the available measurements and revise your generalizations; otherwise you're generally wrong.

To the OP, are you trying to replicate MK262?

 

[Pinecone]

The whole military 5.56 having less capacity than 223 is a myth. It's been measured. The most common military 5.56 case, Lake City, happens to have one of the higher capacities. I suspect this myth comes from the differences between 308 and 7.62x51 (which are usually different).


No. There are no differences between 223 cases and 5.56 cases externally or internally. That's why there are no 5.56 dies. Brass from brand to brand varies, but that has almost nothing to do with being 5.56 versus 223. In fact, some of the least capacious cases are actually commercial 223.

This whole thing is really a problem if you have something such as a Krieger AR barrel with their tight 223 chamber. There are some nice web write ups with pressure testing. I'll see if I can find them.

This ^^^^^^^^^^

The difference in the chamber is that the 5.56 chamber has a longer throat (space before the rifling starts). Long throat means more bullet jump, which is normally bad for accuracy. A .223 Wilde chamber is in between, longer throat than .223, but not as long as 5.56.

 

[Pinecone]

556 with the proper powder can be loaded to factory 556 specs. 223 will suffer over pressure with that same powder, because you will be putting more powder in, due to the internal dimensions of the case. That will also cause serious issues, like case head separation, blown primers, kaboom, and the list goes on.

If you were to use the same powder charge as 556, you would see a velocity drop, due to the unused space in the case.

Dude, you need to get some sleep before you post.

Same powder, same load, bigger case is LOWER pressure.

But in other posts you are saying that mil cases have a smaller volume. But you also say:

556 does have a thicker case wall, but when you use a FL 223 resizing doe, you are not forming the inside of the case, so there is no actual change to the internal dimensions of the case.

Which makes NO sense. If you are size the outside, you also size the inside, as the two are connected.

Check it. Check case volume of a fired case. Resize it, and recheck internal volume. It will go down.

 

[StickShaker]

Dude, you need to get some sleep before you post.

Same powder, same load, bigger case is LOWER pressure.

But in other posts you are saying that mil cases have a smaller volume. But you also say:



Which makes NO sense. If you are size the outside, you also size the inside, as the two are connected.

Check it. Check case volume of a fired case. Resize it, and recheck internal volume. It will go down.

Different rules need to be applied when trying to resize a doe.

 

[alucard0822]

The only real way to tell is work up loads with a chrony, and see the velocity vs charge weight across different brass. I load a lot of 223, the majority is with 55gr Hornady FMJ. By my notes Lake city and Win mil brass tend to take a couple tenths more powder to reach peak accuracy, and tend to produce a few FPS higher velocity, the cases weigh less, and as a result they are my preffered cases. British Radway and Privi cases are the opposite, low charge weights, lower velocity, heavier cases. All the other brands I have mixed in, most other military and commercial fall in a range between. The differences aren't huge, but coupled with PPU crimping their primers in with a jackhammer, and the brass cracking before most others, I usually separate them and Radway from the others, and use them for practice or matches where I don't plan on picking up my brass. If I am loading for longer range accuracy with expensive bullets, or my varmint bolt gun, I stick with lake City, for "bulk" loading a couple thousand for practice and matches, I use a moderate load with most other headstamps mixed.

 

[molonlabe]

I know this has been posted here before but this has been the best read to debunk myth I have found.
http://www.thegunzone.com/556v223.html