After researching " light primer strikes from Shield Plus after Apex trigger upgrade" I found many posts describing poor customer service from Apex Customer service. I called Apex and was told to adjust the "Trigger loop" gap near the end of the trigger bar. I tried everything I could possibly think of. I finally put a trigger bar in from one of my wife's Shields. It worked fine. I was finally making progress. So I called Apex tactical customer service with a progress report. What I reported was a difference (when installing the original Shield trigger bar from my wife's Shield and the trigger bar that I upgraded with the Apex trigger bar upgrade), the gap was different at the sear. I received EXCELLENT customer service from a gentleman by the name of "Doug". He told me to order a Shield Action Enhancement Trigger for a Shield m 2.0 SKU 100-170. Also a M and P sear SKU 100-074. I assembled my Shield Plus with the aforementioned parts and it has worked flawlessly ever since. I thought that I would post my findings. I have seen that many people post the the horror stories and not the entire story when they get excellent Customer Service. I will also say that Doug seemed to know more than the first person. So it pays to call a second time with your finding. Additionally, Doug told me to call back if I had any additional issues. Thanks again Doug at Apex Tactical.