Apparently, Mach 1 and I are on the same page. I have owned a 260 Rem in the past and currently own a 6.5 Creedmoor. Both are great rounds, but I would suggest that much of the current hype surrounding the 6.5 Creedmoor is just that - hype. I have not been able to get my Creedmore up to the performance of my old 260. I recognize that rifle characteristics and barrel length can have some impact on that. But I believe the real difference for me had more to do with my reloading than anything else.
From what I have seen, the 260 Rem and 6.5 CM appear to be close in terms of velocity when comparing load data. However, that is with an unlevel playing field. Min/Max loads for the Rem 260 tend to be 58,500 - 59,600 in pressure. The 6.5 CM is typically run at 60,200 - 60,500. If you push the 260 to those same pressures, then the difference becomes more apparent. I only used Lapua brass in my 260 because it could withstand the higher loading pressures I was using. Lapua doesn't make brass for the 6.5 CM (yet). I have been hearing good things about ADG, so maybe my 6.5 CM can be boosted a little more with high quality brass.
As to the arguments of 'better case design' and 'more inherently accurate', these claims are hard to quantify or justify. However, I would hasten to point out that the 260 Rem is nothing more than a 308 Win case necked down to .264. The claims regarding case design and inherent accuracy of the 308 were and still are the mantra for most of the bench competition shooters, so I am at a loss as to when and how the Rem 260 lost those same attributes.
