That's fine. The insert geometry may not be right for your material. Top rake should probably be positive for soft steel. That appears to be a negative rake insert. The very tip of the insert should be on center, and the rest as it falls. I have a few bars that are high negative, and for roughing, they do well. You could use a round bar holder if you wish to play with the geometry a bit, but it's all about the insert with that bar. The flats are there to orient the bar in a flat holder, just like you have it.