260 Rem. vs 6.5 Creedmoor

[Rhyno]

I choose 260 Remington because I couldn't find 6.5 CM dies, and I had a bunch of 308 brass.

 

[6.5BR]

Natchez had some Hornady dies....

 

[alman1531]

Figured I would give this a bump with a new question on the subject. I have read that a steep shoulder angel on brass means a better powder burn and less case stretch meaning more case life with the 6.5 Creedmoor over the .260 Remington. Has anyone who has shot both seen this to be the case? Forgive me if I am getting too deep into the subject, but I tend to be very analytical.