This is an extruded stick powder. It meters "OK". This is a good powder for 5.56 because at near ~55-60k PSI range or so, you will "probably" be compressing powder substantially with almost any bullet weight and OAL (AR15 OAL which is under 2.260). So it would be hard to make a mistake and do some sort of giant, huge pressure because you just can't get enough powder in the case. For this reason, we find this powder to be friendly to newer reloaders.
This powder has near same burn rate as Accurate 2230, except you can fit WAY less of this into the case. Way less.
We are now near convinced AR Comp is a great choice for 55 grain bullets. Its practically IDEAL. Higher than average velocity, good accuracy, case near full, stick powder low SD so its good for long range too. If your into shooting up to 300 yards, and 55 grain bullets are what you typically use? Check out AR COMP, its hard to beat.