Also have an Apex sear and striker blocker in my Shield 40. I added an over travel stop to the trigger. I made a video showing the results of the trigger stop. I originally used the stock Shield springs and got a 4 pound 4 ounce pull. I put in a stock Glock trigger spring in place of the stock Shield trigger spring. Pull weight went down to 3 pounds 10-12 ounces. Just where I wanted it. Go to the 7 minute 50 second time frame to see the trigger action.
M&P Shield Over Travel Stop - YouTube
I am sure I will get comments about that being an unsafe trigger for carry. Improvements to a gun, that allow you to shoot it better, make it a better carry gun. The lighter trigger pull and trigger stop, on my Shield, helps me shoot it more consistently and have faster recovery. People should practice shooting their carry gun, so they become used to the trigger pull, recoil and recovery, and can shoot it accurately. What makes a safe carry gun is training and practice, and knowing your gun. Also if you follow proper gun safety rules, your finger should be off the trigger until you know your target and are ready to fire. The Shield has a manual safety. I carry with that safety on and practice flipping it off, with my thumb, as I draw my weapon. I might have a better grasp on my reactions in a sress situation, as I spent many years in LE.
I would agree that a long, heavy trigger pull is what an inexperienced shooter should have. This would also apply to those that have experience, but fail to practice often with their carry gun.
Bob