My buddy shoots the 22-250 superformance out of his UMAR, it cronos at 3950 if I remember correctly and shoots nickel sized groups at 100 yds. It does fold the rim back a little on extraction, which does indicate high pressure. I tried a few rounds in my UMAR and it didn't group as well in that rifle. It does come out to be 150 fps quicker than any of my hand loads so it seems to perform as advertised in this caliber.