What would make my AR do this?

[jds holler]

That looks like just under a MOA [assuming the target is at 100 yards].

Have you tried varying the powder charge?
How confident are you that the flyer isn't you?
What barrel is on your AR?

That was the first try with that powder (IMR 4320 @25.0 gr.) I could use less, but not much more. It's slightly compressed now. Bullets were 55 gr V-Max. Two other groups similar with even worse flier. Those fliers went high.

I really want to make that powder work for me because I've got a bunch of it. Goes through my measure with +/- .1 gr. accuracy. jd