I’ve got both, so here goes:
- the AI gains 100+ fps. In my case with 140 gn bullets, it almost 200 when I’m comparing my best hunting load. Rifles are different, with the AI having a longer barrel, so that’s some of the increase. Most of the reloading manuals have them within about 100 fps. Many new AI rifles come with a longer barrel to maximize velocities.
- longer brass life with the AI. Minimal case stretching so you don’t work the brass as hard
- these days AI has better brass with Nosler and Peterson supplying excellent brass. Nosler also makes 280 Rem brass but I’ve never seen it. If you want to form your own, this benefit goes away. It also seems easier to source new 280 AI brass vs 280 Rem. A friend blames the AI for his inability to get new 280 brass. Again, if you can form your own, it’s a non issue.
- these days I think it’s easier to find a new rifle in 280AI, but perhaps I haven’t looked hard enough for 280 Rem
The 280 AI seems to be gain popularity somewhat at the expense of the 280 Rem. With 140 grain bullets I exceed the velocity of several buddies 7 RM. Again I’m talking hunting loads. Most of us load our own, and this surprised me when we were comparing loads. My load isn’t particularly hot, and I think my 26” barrel makes the difference.
I’m sure others will chime in, both for and against the AI. Since I got my 280 AI, that’s become the only long action rifle I use. My 30-06 and 270 sit in the safe. I’m a believer.