split necks?

[Josh11]

I have found a split neck on one of my lapua brass. It is just a small split in the top of the mouth. I dont shoot hot loads at all. I shoot 30.2 gr of rl 15 and cci 450 with smks 107. No ejector marks or other pressure signs. Could it be just a bad piece of brass? I looked through all my brass and thats the only one. Let me know what you think.

 

[camac]

Hi Josh,
How many shots per shell? Do you minimally work your brass? (do you know chamber size vs sized neck/ FL size etc.)
Hot loads can have little to do with it but squeezing neck in and out on every reload will work harden the brass.
Annealing and minimal neck resizing is the way to get more shots from your brass. One shell might be an indicator of what is to come.

 

[Josh11]

I only neck size. Does one have to size every firing? Or could I just deprime? I do not know any of the chamber specs. I think I only have 4 firings through them. I need to anneal them I think.

 

[camac]

Do you have a micrometer? If so, measure the diameter of a fired shell and a neck sized one.
You will have to neck size at least or projectile will just slip in/out. Is there a number on your neck bushing??

 

[fdshuster]

Josh: I keep a count on the number of times I've loaded each box of 20 Lapua 6BR brass. Using both .265" tight fitted necks and .272" no-turn. At 29 and 30 times loaded I'm starting to see very tiny "wrinkles" in the case necks, and I know that splits will soon follow. These cases are close to being tossed out. You can measure the neck diameter of a fired case as it came out of your chamber, after giving it a good cleaning, add .001" to allow for spring-back, and that will be your chamber neck diameter, or within it by a few ten thousandths. You did not say if you are using neck bushing dies and/or using an inside neck expander. My .272" chamber loads measure .269" dia. and I use a .267" bushing, without an expander, so the brass is being worked a maximum of .005". I'm also using the Sierra 107 MatchKing #1570, but with 30 grs. of Varget, BR4 primers, in both my 8 twists. Great accurate bullet.

 

[hammerjack]

I had three out of four new 100 boxes. One had the neck split the other two where split in the shoulder.So you could just have a bad peice of brass.------ Joe

 

[alf]

I have found a split neck on one of my lapua brass.

Just a bad piece of brass. Don't over think it.....

 

[Old Navy]

Ditto what hammerjack and alf posted. Later! Frank