5.56 vs .223 brass

powdergun

powdergun

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I've got a .223 rem bolt action rifle on the way and I'd like to start loading for it. I've read that although the two are similar the throat of the 5.56 is longer. Can I use 5.56 bras in the bolt rifle and still achieve the same accuracy as .223 brass.

Will sizing it and trimming to length as listed in the loading books provide me with decent brass to load with or should I just buy some new .223 brass. The reason for the question is the 5.56 brass is cheap to get as once fired brass.
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Pressure will be higher with the same load with 5.56 NATO cases as the brass is thicker but sizing and trimming works fine in any 223 chamber. NATO brass tends to be fairly consistent so accurate loads could be developed from it from if the utmost accuracy is desired you should weight sort anyway.

I would develop a load with the most easily accessible brass. If you have mountains of 5.56 NATO brass then that would be a good candidate. Personally I don't have too much NATO brass so I tend to develop accuracy loads with civilian brass as more of it is just a trip to the store away.

Also if the NATO brass happened to be fired in a machine gun then it will often be hugely oversized due to extremely large machine gun chambers. I have some 7.62 NATO brass I got from a friend that stick in the sizer no matter how much lube I use because they are so big. After 3 pulled off rims in 10 cases with loads of RCBS lube I just put them aside for possible future use for something.
 
5.56 and .223 cases can be treated the same for load development purposes. Unlike 7.62 NATO/.308, military cases do not have significantly reduced case capacity compared with commercial ones.

http://www.m4carbine.net/showthread.php?t=55149

Military brass will typically have the primer crimped in place, which will interfere with seating a new primer. A countersink bit in a drill will quickly remove the crimp from the primer pocket.
 
i reload for bulk plinking, and i combine all my 556 and 223 brass and use the same load without issue. Now for pushing out long range there might be a difference who knows. so this comment was completely useless :D
 
The SAAMI .223/5.56 interchangeability warning came out in 1979 just before the U.S. military came out with the higher pressure NATO SS109; U.S M855 round. Simple thumb rule, U.S. made M193 ammunition is loaded to the same pressure as .223 ammunition at 52,000 cup and was fired from M16 rifles with a short throat. NATO M855 ammunition is loaded to 55,000 cup and requires a longer throat the presently made M16/A4 rifles have.

I have two AR15 rifles and a Stevens 200 .223 bolt action rifle with a 26 heavy barrel, my Stevens 200 has a longer throat than my two AR15 rifles. (.0566 vs .0500)

The majority of short throated .223 rifles will have a 1 in 14 or 1 in 12 twist and the rest will have chambers and throats big enough to fit a firearms company lawyer in. (meaning they do not want lawsuits so the throats are longer on the majority of newer .223 rifles)

556and223chambers_zps87d293d3.gif


5.56 vs .223 – What You Know May Be Wrong
http://www.luckygunner.com/labs/5-56-vs-223/


HOLLIGER ON .223/5.56 CHAMBERS
http://www.radomski.us/njhp/cart_tech.htm

Military 5.56 Lake City cases are made of harder brass and are "NOT" thicker.

556hard-a.jpg


hardness-a.jpg


I have three five gallon buckets of U.S. military Lake City 5.56 brass, below is just one five gallon bucket being prepped for reloading.

halfdone.jpg


NOTE: Some batches of Federal American Eagle 5.56 case have thin web areas and have loose primer pockets after the first firing.

FCvsMilbrasssectioned_zpse9aa074d.jpg


To answer your question YES you can use 5.56 brass in your .223 and military brass is a higher grade of brass and designed to withstand higher pressures in larger military chambers.

bucketsofbrass.jpg
 
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