After trying a few things, and reading a lot, I think I have discovered I have headspace issues.

So the barrel was replaced on my 7mm Rem Mag in April of 2011. Due to lots of "stuff" going on, After following the "break in" process recommended by Shilen, I quickly found an adequate load at the end of the summer last year with new brass and once fired brass with IMR7828 and 160 Accubonds. No obvious pressure signs and they shot well. Took my first branch antlered bull elk at a good long poke out there and cleaned it up nice and put it away for the year.

This fall, after bringing the rifle back out, I shot a few more of last years loads and checked zero. All was well and I loaned the rifle to my brother for a hunt he was doing. It worked well for him and after he was done, we met up on a deer hunt with our sons. I took the rifle from him then and then cleaned it up well.

Last month, I came here on the fire and expressed a concern I had with "wierd" pressure signs I was having. Shooting during a snowy November trip to the range, the rifle began exhibiting excessive pressure signs. I then resized the brass fully (normally only size enough to get a "crush fit" in the chamber)and dropped down the charge. I then fired a few more rounds, even over a chronograph, and was getting a bit of a hard bolt lift. It was then that I saw my first headspace expansion failure. Thinking my brass had become work hardened or was just beat up too much, I threw it out.

So, I loaded up some once fired Nosler brass, dropped the powder charge pretty significantly, and then went to the range.

Yesterday, I fired three shots, all different bullets with once fired Nosler brass. I used IMR7828 and 160 Accubonds, 160 Partitions, and H1000 with 168 Bergers. Choosing the lowest charge of the newly rolled loads, I shot my first shot. Case separated, So, I loaded a different load with a lower powder charge and a Partition bullet and fired. Case separated. So I tried the Berger and H1000 powder and again had a case separation. I was done. I put the rifle away and will now take it to the gunsmith to have the headspace checked.

The only thing I can think, is that all of the brass I used last year developing the loads etc., were stretching excessively and I didn't realize it. This year, after resizing it, it finished it off. Do you think I am correct?

Reading in the old Hornady manual, my Nosler manual and several other places on the web, it seems that I have a perfect example of "excessive headspace".

Any of you had this issue before?

FH