M17 shooting so low it’s barely on paper?

My M17 guys out there has anyone experienced there M17 hitting really low and I mean like barely on paper or at the bottom of the target. My M17 is hitting like 3 to 4 inches low of the bulls eye. I aim the sights using a combat hold so the front sight is covering the bulls eye on the target. This is also my second M17 I had one about 5 years ago and had the same problem and sold it because I found that unacceptable. This is my second (thought the second time round would be different) and it is brand new never fired and it’s doing the same thing. Has anyone else experienced this with there M17? Should this be sent back to Sig? I have plenty of other handguns and shoot them all just fine but this one for some reason doesn’t. I have other p320s that shoot just fine as well so I’m not a stranger to the p320 platform either.