223/5.56

[Fire Guy]

I am sure this discussion has been hashed out before but since I'm new I'll plead ignorance.

Just getting back into reloading after a 25 year or so hiatus. I'm checking my brass and finding a bit of a discrepancy in the length of once fired brass (223/5.56)

I'm getting lengths from 1.738 to 1.760. Mostly around 1.748 to 1.755. I'm sure this isn't going to be a problem, since I have already fired these rounds and had no issue. I had planned to buy a case trimmer but now I will wait. I know I will need one but not too soon.

Also what exactly is the difference between the two calibers? I'm not seeing a lot in size powder charge just bullet weight. I do understand the 5.56 is supposed to create higher pressures.

All suggestions and remarks are welcome.
Thanks.

[JackEllis]

If you're reloading, you need to ream the primer pockets on 5.56 cases to get rid of the crimp before you try to reprime them. I have a .223 and will not use 5.56 factory ammo in it because apparently the 5.56 is loaded hotter than .223. I also use .223 load data and ignore 5.56 load data.

I have the Lee case trimmer that fits in a press and can be powered with a drill. Seems to work just fine, though you do need to get dies for each caliber you reload (I reload 3 calibers).

[baih777]

Weigh the cases. Usually the 556 has a thicker case. You reload to 223 data. I have not seen 556 data yet.
Google will have more specific info for you.

[jessdigs]

I may be talking out of school here, but I have heard that the 5.56 case is different
The throat and angle of the 5.56 NATO is slightly different/longer from that of the 223Rem.
You can use 223 in a 5.56 but not the other way around because of it



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[dwalker]

I have only posted this like a dozen times, but it does help prevent me from having t explain it a 1000 times.

http://www.luckygunner.com/labs/5-56-vs-223/

[TomReloaded]

For reloading, it's all treated as 223. Trim to 1.750. load until it's accurate, which is damn near always under max for saami.

A lot or maybe even most 223 chambers are cut so loose and long that they're really 5.56. lawyer chambers, maybe.

[FLIGHT762]

This ^^^^^^ is a good article to read. You'll notice the author did not blow up or damage his 223 Rem. bolt gun in using 5.56 ammo these tests. I shot a lot of US M 193 5.56 ammo through my Remington 700 223. Before there was this warning from SAAMI. The SAAMI warning is cautionary notice to be aware of.

Another good article regarding 5.56 brass VS .223 Rem. brass http://www.accurateshooter.com/cartridge-guides/223rem/. Scroll down the page and there is a test of case capacity of 223 & 5.56 cases. There are some 5.56 cases that have more case capacity than 223 commercial cases.

The reality is there is no clear 5.56 cases are thicker / heavier / have less case capacity than 223 cases. Each manufacturer has their extruding process and 223 cases can have less or more case capacity than 5.56 cases. There are also some 5.56 cases that are thicker / heavier. What I've found over the past 40 years in reloading the 223, you need to weigh you cases and see what capacity they have and reload powder charges accordingly. There cases they weigh at the 100 grain area are going to be cases that have less capacity.

Many people get confused because of the 7.62 NATO VS 308 Winchester brass issue where 7.62 NATO brass is thicker / heavier and has less case capacity than commercial cases. This was also mostly true with the Military 30/06 cases being thicker / heavier than their commercial counterparts.

[dwalker]

For reloading, it's all treated as 223. Trim to 1.750. load until it's accurate, which is damn near always under max for saami.

A lot or maybe even most 223 chambers are cut so loose and long that they're really 5.56. lawyer chambers, maybe.

I have not found that to be true using the powders I use. In fact I loaded well over max for one powder- by more than a full grain- to get best accuracy.
My 77gr BTHPM load was over max and right on the verge of being unsafe. Like on a hot day you would not load these into a gun right after autoburn or even a seriously fast mag dump, to do so would almost beg for a pressure spike which could kaboom the rifle. I just recently backed it down a couple tenths of a grain for a safety margin.

5.56 is not a SAAMI load and therefore there are no loads out there for it available in off the shelf reloading books, which is why pretty much everyone loads to .223 pressures and does just fine.

[Fire Guy]

I do appreciate all the responses. Even though my AR is chambered in 5.56, I am very concerned about the pressures. I will read the articles linked here and digest them. Weighing brass is something I used to do for competitive shooting in years past, I hadn't thought to do that to be sure my 5.56 brass was just that. I do pick up brass at there range that looks to be in good condition to reload, so this information will be handy. Thank you all for the input and any other responses are welcomed.

[dwalker]

I just load it all and it works out. Since I very rarely get more than 1 or 2 loads through my brass before its lost at a match, I cant say how long the brass will last, but if you just load .223 loads and use good reloading practices- like working up to load, using chrono, and reading your brass- you will be fine. Its only when you start doing stupid things like trying to throw 77gr BTHP-M's downrange at 2850fps or more that you get into that you get into that iffy realm.

[McGuiver]

223/5.56

Weigh the cases. Usually the 556 has a thicker case. You reload to 223 data. I have not seen 556 data yet.

Google will have more specific info for you.

I found some 5.56 load data. This is from what the military loads are spec'd from.









Here is the original link in PDF form...

http://www.americanreloading.com/img/AmericanReloadingWC844-5.56NATODATA.pdf

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