I have used R26 in both the 30-06AI as well as the 280AI with very impressive results, both velocity and accuracy. I know it is used in many other cartridges, but those are the two I have tried. I will say this, it likes three things to do it's best...a long barrel, a heavy bullet and room for enough powder. In fact, even with compressed powder charges in my AI rifles I saw no signs of pressure whatsoever. It seemed as if I could not get enough powder into the case to cause a problem. I say this with caution and it seemed to good to be true...wanting a bigger case to see just how much velocity I could get before the pressure issue kicked in. R-26 is fantastic powder to be sure. Almost makes me want to build a 7mm Magnum as much as I hate a belted case!!!