does anyone have any experience with these?
I like the idea of the straighter case for reduced case growth and perhaps a little easier speed generation for rams
Dies are not too dear or hard to get and cases can be cheaper than lapuas.
There some positive reviews on some of the benchrest sights for some of their longe range matches.
I would be thinking of using a sako 75.

This is just me, but I wouldn't do it. First, you'll have to go thru the time and cost to fire form cases. And second, the 260 has plenty of case capacity to get the ram load up to speed. There's no need to go much faster than 2700 fps as the extra velocity causes the bullet disintegrate before it transfers the momentum to the target that results in a rung ram.

On the other hand, if you're looking for a "do it all" cartridge for hunting, long range benchrest, and silhouette then an AI will make sense.

We have built several 260 AI's but I think they have more power then needed for silhouette. They make a great long range hunting rifle using a short action and generate speeds aproaching the 6.5 X 284.
Pete