I knew several shooters who went 260 AI for their comp rifles, mainly Terry Cross. We spoke about it years ago (after they wrote his article about it), and the gain over a normal 260 was right at 75-80 fps with the same H4350 powder. If you went to a double base powder, like the R17, R26 or similar powder, you can gain more than 75 fps over the H4350, but you could also start with a double base powder to begin with. The consensus on the 260 AI was that the minimal gain was not worth the head ache of fire forming and such with normal temp stable powders. You can always improve the speeds with a double base powder, at the risk of being temp sensitive.

Most of the time when you go to an AI, you gain about 80-100 fps. The 7-08 AI rounds with Varget we have gone to yield about 120 fps gain with the 162 grain bullets. Heavier bullet and higher yield does make it a little more attractive.

I wish there was real load work up with pressure testing done. It makes zero sense to me that a 260 ai only gains 50% of what a 7mm-08ai does even though its the same case and dimension except the diameter of the bullet.

I have absolutely no experience in owning any of these but I do plan on getting a 6 5 bore rifle at some point. Couple that with the fact that reloading isn't as hard and, more importantly, more entertaining than o thought. So I definitely want a non typical caliber.

6.5cm is exactly what I'm sure everyone says it is but to me isn't cool anymore. This 260ai and 65.x47 seem cool. I presume with habdloading one can make it just as accurate.