.223 Case Length

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OldPPC

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I have ready access to a lot of once fired .223 brass. None of it is military but some of it is from law enforcement firing range sources. I've checked case length on a lot of it and I find that it ranges from about 1.754 to 1.768 and I'm puzzled as to why factory .223 ammunition would vary that much. Most of the reloading manuals I've consulted publish a "standard" of 1.760 which, coincidentally, is just about the center point between the two extremes I've experienced. Is this a common variance?
 
Full length size before you measure, you will notice it grows when you size it.
Varibles in length can be caused by brand, is it once fired, the type of firearm it was fired in, and sloppy chamber versus tight chamber.
I have found that cases from the same manufacturer fired in my Colt AR tend to be very consistent in OAL.
 
If the lengths you mention are after the cases have been FL sized it's likely the long ones were fired in oversize chambers. Kansasvet is correct that brass will lengthen on FL sizing, and more in oversize chambers.

Most new factory .223 brass is not much longer than 1.750" and a lot of it isn't even that long.
 
Thanks guys. That helps a lot. As I pursue the subject it appears to me that the 1.760 is intended to be a case maximum length. Who ever shot this stuff that's 1.768 must have one huge chamber; at least compared to mine. I can't even close the bolt on a case longer than 1.760 with the bullet properly seated. I want to avoid anything shorter than 1.756 because my Nosler 50g spitzers, clearing the rifling by .002, come pretty close to contacting the 24.9g powder charge as it is.
 
OldPPC said:
I can't even close the bolt on a case longer than 1.760 with the bullet properly seated.
Click to expand...

The issue closing the bolt is normally due to the position of the shoulder of the case but can be because of the neck.

It all depends on the chamber that they were fired in. For safety's sake throw the ones that are excessively long. They could be 1 firing away from a case head separation.
 
Uniformity is far more important than case length. Put your chambering reamer on a comparator and you might find that your chamber neck is longer that 1.760.

Don
 
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