Reloading 5.56

[geist262]

I have 223 and 5.56 cases. From the research I have been doing, the jury is out about case differences. I have seen where people have cut the cases in half and both look identical to each other. That said, is there a difference between the two? All my loading manuals have 223 but not 5.56. Can, I load these all the same, or is there a reduction for 5.56? Any reloading data and/or advice would be great. Thank you.


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[Miata Mike]

When you resize the case, the shoulder will be a sliver different than when it was originally 5.56 if I am not mistaken. As always, start lower and work your loads up.

 

[rcmodel]

Size, trim and weigh them on your powder scale.

If one is heavier then the other, it has less capacity.

In fact though, case capacity with GI 5.56 is seldom a problem.

Just treat them all as .223, because that is what you are reloading.

rc

 

[Lennyjoe]

^^^concur with the above post^^^

 

[BruceB]

Several years ago, I weighed cases of mixed manufacture and a dozen or so assorted headstamps, including BOTH military and commercial origins.

The total maximum weight variance, from lightest to heaviest, was only about ONE GRAIN. That much variation is essentially meaningless.

I still usually keep the rounds sorted by headstamp, mostly for appearance's sake, but now I only weigh cases when a new headstamp appears. This is just a check to ensure that the 'new' brass is in the same weight bracket as the earlier cases.

 

[Walkalong]

Some .223 commercial is heavier than some 5.56 military brass, and vice versa. My plinking loads are tested to be safe in the heaviest cases, so I don't have to worry about what brass I use. While loading, every once in a while the powder comes way up in the neck of a piece of brass compared to all the others. I just scrap it.

Accuracy load in .223? Use all the same head stamp or weigh all the cases, or both. Pick a weight range you are comfortable with. That may be a 2 Gr spread, or it may be a 1 Gr (Or less) spread. It's up to how OCD you are, and how accurate your gun/load can be. I used to try to get a .5 or less spread with 6 PPC brass.

They don't sell 5.56 dies, only .223. Whether the case started out as a 5.56 load or a .223 load matters not. IMO, the only difference in a .223 or 5.56 load with handloading, is the pressure level loaded to.

 

[Laphroaig]

Here's my .02

Differences between the 2 designations are 1) 5.56 cartriges have a higher allowed chamber pressure than .223 and 2) 5.56 chambers have a longer leade than .223. If there is any difference in outside brass dimension it is negligable and won't matter after you run it thru your sizing die anyway.

I seperate brass by headstamp and load both commercial and military with the same data. I don't load maximum and have never noticed a difference in performance between brass types with my loads.

Laphroaig

 

[1KPerDay]

On the subject: I'm getting my first .223 loads going (after struggling with sizing but that's another thread ), and have a question on safe cartridge headspace. I have a drop-in type wilson case gauge. If I size the cases so they measure between the min and max "steps" on the gauge, they should be good to go, right? Loading for semi-autos, multiple rifles.

Thanks

 

[Walkalong]

Yes, assuming correct chambers. I size .223 to fit a Wilson gauge and case life is very good in my guns.

 

[geist262]

Thanks guys.


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[1KPerDay]

Yes, assuming correct chambers. I size .223 to fit a Wilson gauge and case life is very good in my guns.

Thanks.

 

[Allen in MT]

I shoot a Cooper 223. I'm working up a load and at this point have a load that shoots all holes touching at the 100 yd. Im using 24.5 grains of H335 powder. Would it be safe to use the same load in resized 5.56 brass.
On my 1st time reloads I uniform all the primer pocket holes, de-burr the inside of flash hole trim case if needed clean and resize.
Will decrimp primer hole if I can use the 5.56 brass.
thanks

 

[geist262]

I shoot a Cooper 223. I'm working up a load and at this point have a load that shoots all holes touching at the 100 yd. Im using 24.5 grains of H335 powder. Would it be safe to use the same load in resized 5.56 brass.
On my 1st time reloads I uniform all the primer pocket holes, de-burr the inside of flash hole trim case if needed clean and resize.
Will decrimp primer hole if I can use the 5.56 brass.
thanks

Scroll up, I believe RC and Walkalong covered your concerns. I pretty much wanted to know the same thing. You load them as .223.


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[cfullgraf]

Several years ago i weight several hundred W-W 223 Remington cases and several hundred Lake City 5.56 NATO cases. The Lake City cases were lighter than the W-W cases.

Granted, only two data sets but it concurs with rcmodel's and Wlakalong's comments.

My plinking loads are designed to work with any case. If I am looking for more precision like for service rifle competion, I work up the load with a single head stamp and stick to it.

The external case dimensions between 223 Remington and 5.56 NATO are the same. There are lots of different chamber dimensions out there for 223 Remington/5.56 NATO, each with its own little nuances and differences.

 

[Walkalong]

Any time you work up to a max load you need to take case weight into consideration. I log case weights for target loads and max loads.

So the answer is to check the case weights on the ones you are using now and the ones you want to use next.

I would love to have a Cooper one of these days. I have drooled over them a time or two.