Rethinking my original plan. I have a great load with 150 Eldx out of my 7mm-08 (2780 fps) and another great load with 162 Eldx out of my 7mm Rem Mag (2980 fps). A 280 really doesn’t get me anything I don’t already have.
The 7mm-08 isn't a good comparison to the .280 AI since it is short action vs. long action and only has ~60% of the case capacity of the .280 AI). It is a great round, but is an apples to oranges comparison to the .280 AI in my opinion.
But the .280 AI and the 7mm RM are very similar in performance. The 7mm RM has more case capacity, but is less efficient than the .280 AI. But, as has been said, there is nothing the .280 AI will do that the 7mm RM won't also do. If you didn't already have a 7mm RM I would say get the .280 AI. Since you already have a 7mm RM, I don't think you are gaining anything by getting a .280 AI other than more load data to obsess over and a "new" rifle to play with.
