Don, don't worry, I had the same issues when my M4 was new. Now that it's broken in, my M4 cycles everything flawlessly, including 1 oz/1200fps light target loads. Your gun may take a little longer to break in than your dad's - every gun is different.
Mine also has the "peening" around the ejection port. This just means your gun isn't a safe queen.
btw, I think it is very cool that both you and your Dad have M4s!! Pictures?