New Win. 243 brass won't hold bullet

[vonb]

I have some brand new .243 Winchester brass that is brand new that was purchased 6-7 years ago. The other night, I went to load some rounds and ran into an issue. As always, my first step is to run them through a Forster F/L sizer (with expanding ball in place) using Imperial wax. I mainly do this to round out the case mouth.

After performing the step above, I went to charge and seat and the seating was where I ran into an issue. I was seating 100gr Remington Core-Lokts and after seating, I noticed that the case mouth was too large to reliably hold the bullet in place. Therefore, just shaking the case would move the bullet. Where have I gone wrong here?

I have performed these same steps many times in the past and no changes have been made to my die. This setup has worked well using 85gr HPBTs and 87gr VMAX. I'm using a Forster Co-Ax press.

 

[Whelen Man]

Good question. If you've got a caliper check the diameter of the 100 gr. Remingtons compared to the other bullets you've loaded in the past. Then check the outside diameter of the neck compared to loads from the past. That should tell something as to whether it's the brass or the bullet. Something is weird here. The only thing that has changed is the bullet. With the expander in place the brass shouldn't be the problem with new brass unless something happened to it during storage to harden it where it won't size properly.

 

[Sniper]

I had some Winchester .308 brass that was like this, it would not hold a .308 bullet with any neck tension at all. I could easily push the bullet into the case with my fingers. I resized it all to 7mm-08 and it worked fine for that caliber.