Response from S&W Customer Service:
Sir, unfortunately we don't have other front sights for the M&P. The accuracy standard is 4 inches at 25 yards, if it is outside our standard you should send it in for warranty service. Please see the attachment for shipping instructions.
I have been watching the front sight very carefully during dry firing. I don't notice it moving up or down, however, I
DO notice it snap to the side sometimes when the firing pin hits (it is NOT my trigger movement that causes this front sight jump).
I did not try 25 yards (I don't think my range is over 50 feet). At 30 feet the shots were very low and left of POA. Dang it, I was hoping I could avoid sending it back to S&W.
I will try it at the range one more time and take extra great care in monitoring my trigger control to see if it really is operator error. Still, I am not a competition target shooter, and I can keep it on the target paper (mostly) at 30 feet. Good enough for multiple COM shots if ever necessary.