Thanks. If I ever get around to building one it may end up being a coin flip. I'm familiar with Zak Smith's articles, I've read the ones he has on his website for all three cartridges. Interestingly, he is sticking with the 260, maybe because it's the one he started with.

Daryl,

All three cartridges are based off of the 308 case so there is no difference in case head dimensions. The main distinction is Lapua went with the small primer so you could consider it a stretched and necked out 6mmBR. They may have tailored the wall thicknesses some as well to handle the pressures. The main drawback with the Creedmore is the Hornady brass is reputed to have a short life due to the primer pockets loosening up.