I've shot them in my 26" 224 Valkyrie. My MV is around 2700 fps... a pretty tame load actually. Hitting the 600 yard target at 1850 fps (according to ShotMarker) and above Mach 1.2 at 1100 yards. Accuracy is quite good, but I do get the odd flyer. Like 9 grouped into a nickle and then one an inch low at 100 yards. Same sort of thing at 600. Most out of 25 shots into 1 MOA but then one off in la-la land.
I did find that I need the updated Hornady seating stem in order to seat these without marking up the bullet. I also used a Sinclair expander to make sure I'm getting consistent and light neck tension. I think I need to try chambering these more gently to see if that helps with the flyers. I wonder if I'm getting bullet deformation on chambering when not being careful.
One note about the Hornady A-Tip seating stem: it works well with other 224 caliber high-BC bullets, like the 90 SMK etc, but if you use it for that it will mess up the seating stem. It will expand the opening of the stem a bit and then when you go back to the A-Tip, you'll get marked up bullets again. Recommend you get two, one for the A-Tip and one for everything else.