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  #1  
Old 03-05-2017, 12:00 PM
captron captron is offline
 
Join Date: Oct 2014
Location: Texas
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Default .223/5.56 case prep question

Hopefully someone can answer this question?? If 5.56 once fired military brass is resized using proper die set for .223 Remington, will this brass chamber and function properly in my. 223?? There seems to be a difference between the two rounds as originally manufactured. I have access to a couple hundred rounds of once fired 5.56 military if I can use them in my .223?? Thanks for any advise.
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  #2  
Old 03-05-2017, 12:07 PM
CDRT CDRT is offline
 
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Yes, you can use them. I have resized military brass and used it in my Rock River with no problems. Also, in a Mini-14. I did use an RCBS small base die.
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  #3  
Old 03-05-2017, 12:17 PM
cdockter cdockter is offline
 
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The only brass I own and use is LC and WCC military once fired, perfectly OK to use in .223.

As always, make sure to trim the neck to the correct length. One difference between 5.56 and .223 Rem. is in the chamber throat length (leade), with .223 being shorter, so untrimmed 5.56 MIGHT jam the brass into the lands, which might raise pressure to unsafe levels.
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  #4  
Old 03-05-2017, 12:51 PM
captron captron is offline
 
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Thanks for the info. guys. I was pretty sure that trimming oal would be necessary assuming all else was good, but just wasn't sure.
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  #5  
Old 03-06-2017, 12:44 PM
Pinecone Pinecone is offline
 
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The cases for .223 and 5.56 are the same. 5.56 is loaded to slightly hotter than .223, and may not be safe in rifle chambered for .223.

The difference is that the .223 chamber has a shorter throat, which increases pressures.
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  #6  
Old 03-06-2017, 02:26 PM
captron captron is offline
 
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Quote:
Originally Posted by Pinecone View Post
The cases for .223 and 5.56 are the same. 5.56 is loaded to slightly hotter than .223, and may not be safe in rifle chambered for .223.

The difference is that the .223 chamber has a shorter throat, which increases pressures.
Thanks, I will probably start case prep this pm.
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  #7  
Old 03-07-2017, 03:23 PM
bigedp51 bigedp51 is offline
 
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Quote:
Originally Posted by Pinecone View Post
The cases for .223 and 5.56 are the same. 5.56 is loaded to slightly hotter than .223, and may not be safe in rifle chambered for .223.

The difference is that the .223 chamber has a shorter throat, which increases pressures.
Both the .223 and 5.56 are loaded to 55,000 psi SAAMI pressure testing methods. And the throats make the pressure difference and the throat in my Savage .223 with a 1 in 9 twist is longer than the throats in my AR15 rifles.




MIL-C-63989A(AR)
MILITARY SPECIFICATION
CARTRIDGE, 5.56MM, BALL, M855

3.7 Chamber pressure. The average chamber pressure of the
sample cartridges, conditioned at 70 degrees + - 2 F shall not exceed
55,000 psi. Neither the chamber pressure of an individual sample
test cartridge or the average chamber pressure plus three standard
deviations of chamber pressure shall exceed 61,000 psi.
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  #8  
Old 03-07-2017, 04:01 PM
HighpowerRifleBrony HighpowerRifleBrony is offline
 
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Quote:
Originally Posted by cdockter View Post
The only brass I own and use is LC and WCC military once fired, perfectly OK to use in .223.

As always, make sure to trim the neck to the correct length. One difference between 5.56 and .223 Rem. is in the chamber throat length (leade), with .223 being shorter, so untrimmed 5.56 MIGHT jam the brass into the lands, which might raise pressure to unsafe levels.
Neck and throat are different things.
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  #9  
Old 03-07-2017, 05:05 PM
A Seabee A Seabee is offline
 
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Just remember, the inside dimensions are different....

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  #10  
Old 03-07-2017, 06:22 PM
bigedp51 bigedp51 is offline
 
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Quote:
Originally Posted by A Seabee View Post
Just remember, the inside dimensions are different....

Federal cases were said to have soft brass and this was because of the thin flash hole web that quickly led to over sized primer pockets. And in the illustrations below you will see the Lake City cases have the most case capacity.





Bottom line, Lake City and commercial contract 5.56 ammo for the military are all made to the same standards and use harder brass. And this came about after the 1968 Congressional hearings on the jamming problem with the M16 rifle.

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