I have three CCW's that I rotate depending on weather/clothing/mood...I shoot two much better than the other?

I has, Shield performance center 9mm, Sig P938, Glock 43.at 10-15 yards, I could hammer in nails with the shield and the G43 (especially the shield).However, even at less than 10 yards, I find myself wholly inaccurate with the p938. I've put around 400 rounds through it and I can't seem to improve with it. It's all over the place. It won't group shit and 90% of the time I miss the target completely.The trigger has a short travel distance, but it has a heavy ass break. Could that be the issue? Also, I got it used, so the sights might be off. How do I adjust them?I know the 938 uses a combat sight picture and the dot should go on the intended point of aim rather than the top of the sight. Still, doesn't make much of a difference.The gun feels great to shoot, and I've only had one failure out of 4-500 rounds (double feed, it was really dirty). This is my second one and I would hate to get rid of it again. I really want to master this little bastard but I'm running out of patience/ammo -_-...Halp?Wish I could tell you where the shots are going but I miss the target entire.Most are low I think...but then when I adjust POA, most are high.It's maddening. via /r/CCW http://ift.tt/2mTSJWF