Quote Originally Posted by KMW1954 View Post
Just to clarify, this is not new brass and it is not short brass. This is all Hornady brass. This has been fired in this rifle 3 times and processed and reloaded by me to be used as target match ammunition so it has been thoroughly inspected and measured to be fired in this rifle. So indeed it all has been head spaced to this rifle. Primer pockets have also been uniformed and measured and primer seating also measured. Every round that has failed to fire has measured .005"-.007" shorter than the loaded length measured to the shoulder datum line. As was just brought up by my mentor I have not tried to chamber this and then eject and measure before firing. All primers have also been measured after FTF and all still measure the exact same as before firing. Primers have not moved.

So I can understand the light primer strikes and possible weak springs but I cannot account for the shoulder movement which is only appearing on the rounds that do not fire.
So after being chambered, FTF and extracted, the cartridges that FTF are shorter than the other reloaded cartridges that weren't chambered ?
I'm guessing your just neck sizing and not full length sizing ?
I would thoroughly clean your die set and see what happens.

SJC