I purchased a box of them about a month ago for my AR, it's built based on an Anderson Lower and 18.5 inch barrel with a Wylde chamber. I worked up to 26 gr of CFE 223, tried a three shot group at 100 yards, the bullets hit all over the place, about a six inch group. I called Hornady and the tech that I talked to told me that due to their length they have to be seated to 2.360 oal and single loaded in ARs because of the magazine length restrictions, 2.260 is the max oal if you are using a magazine in your AR. I gave the rest of them to a friend who has a 223 bolt action. I would try the new Sierra 77 gr tmk bullets, I am getting groups averaging .800 with CFE 223
