Different lengths for once fired brass?

Nuclear Worker

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For my 6.5x284 using Lapua brass. My new brass measures 1.815 to shoulder. After fire forming multiple times it measures 1.818 I use a Forester full length die with the rod removed. Then a Lee collet neck die. Never had any problems. I just shot some new 1x fired brass. 25 total, I checked 4 of them and they all measured 1.818 so I resized some more. When certifying they were correct to my surprise they were not. Some were 1.8155 down to 1.8130 ? So I checked some that I didn't resize yet and they also were below 1.816 already. So I stripped my bolt and tried to chamber them . Won't close so I thought I had to resize them. I read somewhere today that you can resize without bumping the shoulder? And that new brass sometimes takes several fire forming before it grows enough to bump shoulders back? If this is true do you back your die off so there is no shoulder bump but it will still resize the case? Last question can I still use the brass that has excessive shoulder bump and just re fire form it?
 
Trying to access my prior knowledge as I have been through this as well, are you using a 6.5x55 LCD with a washer as a spacer? I switched from a Redding body die to FL sizing and then using a LCD, I realize this adds a step but the results were exactly what I was hoping. I do remember the virgin Lapua brass being very short out of the box and it took several firings for them to fit the chamber correctly. How long were the cases that wouldn't chamber?
 
OK, this is a common problem. You have measured the base to shoulder datum, but you haven't measured the case at .200" up from the base. This is often the sticking point.
My remedy has always been to use a Redding Body Only Die, it touches nothing than the case body at the web.
Now, the reason is that not all cases are at the same dimension, even same brand, in different lots of brass.
So, if they are larger at the web, or expansion line, than the other brass, this is most likely your problem.

Cheers.
 
Trying to access my prior knowledge as I have been through this as well, are you using a 6.5x55 LCD with a washer as a spacer? I switched from a Redding body die to FL sizing and then using a LCD, I realize this adds a step but the results were exactly what I was hoping. I do remember the virgin Lapua brass being very short out of the box and it took several firings for them to fit the chamber correctly. How long were the cases that wouldn't chamber?
That's what I don't understand they were shorter than 1.816 already? So I tried them in the chamber but couldn't close the bolt without a lot of pressure. So I assumed I had to resize them. So when I did they fit but are more than.002 bump. They were like 1.815,1.814,1.8135 after running through the die. Don't know what you mean by 6.5x55 LCD? Using Forester coaxil
 
Yes, LCD is Lee Collet Die, unless Lee has recently produced one for the 6.5x284, some including myself use a 6.5x55 die and a steel washer over the case after the case is in the shell holder for a spacer to neck size. Are you using the Hornady 420 comparator insert to measure the base to datum line distance? My barrel is an xcaliber on a Savage action so I purposely headspaced the barrel a touch short so my sized cases may be a little shorter on headspace than yours.
 
That's what I don't understand they were shorter than 1.816 already? So I tried them in the chamber but couldn't close the bolt without a lot of pressure. So I assumed I had to resize them. So when I did they fit but are more than.002 bump. They were like 1.815,1.814,1.8135 after running through the die. Don't know what you mean by 6.5x55 LCD? Using Forester coaxil
Take a case that does not want to chamber paint the outside with a black sharpie, then chamber it, the sharpie will rub off where the tight spot is and you'll definitely see it.
 
I just happen to be loading and sizing brass for my 6. 5 x 2 84 Norma. as mentioned earlier I like the Redding set with the separate body die, the smaller die only sizes the body the one to the left only sizes the neck
image.jpg
the one missing seats the bullet it is in my press at the moment.
image.jpg
 
Yes, LCD is Lee Collet Die, unless Lee has recently produced one for the 6.5x284, some including myself use a 6.5x55 die and a steel washer over the case after the case is in the shell holder for a spacer to neck size. Are you using the Hornady 420 comparator insert to measure the base to datum line distance? My barrel is an xcaliber on a Savage action so I purposely headspaced the barrel a touch short so my sized cases may be a little shorter on headspace than yours.
Yes I'm using the 420 comparator. I sent several fired cases to Lee and had them make a custom LCD for.002 neck tension for my chamber.
 
So after sitting for 24hrs all of the cases had some spring back. The ones that were close to begin with between spring back and running them through the LCD brought them into spec at 1.816. The only thing that I can see for the cause of this was being new brass. I still have 10 cases even after neck sizing are still short as in 1.814-1.815 Can I still just load them and re fire form?
 
One other quick comment. You do realize that the Lee neck collet die is not supposed to have any affect on the base to datum measurement. This die should size only the neck, so if you length changed by resizing in the neck collet die, there is something else going on.
 
I just happen to be loading and sizing brass for my 6. 5 x 2 84 Norma. as mentioned earlier I like the Redding set with the separate body die, the smaller die only sizes the body the one to the left only sizes the neckView attachment 531038 the one missing seats the bullet it is in my press at the moment.View attachment 531043
It seems to be working for me!
IMG_6011.jpeg
 
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