Copper Creek has modified cases

[skyrep]

Grayfox,
which gauge did you use to measure the Datum on you Cooper Creek Modified Case.  Did you use the Hornady or the Forster.
I have a Forster and my case measured 1.185.  the OAL is same as your measured.

Those are the same numbers I am seeing, 1.183-1.185, I use the Hornady guage.

Those are the numbers for factory ammo and my full length resized as well. I am going to try and bump the shoulder less next time I reload and see if it cycles.

my fired cases have been measuring 1.194-1.195 (measured with the forster guage).  i'm bumping the shoulder back to 1.191 using the Wilson Bushing FL sizing die.  I have a Uintah Precision Bolt Action Upper on an Anderson Lower.