Wrong mounting screws - trigger feel changes - American Tactical Arms ATA19 Badger Stripped Slide with Optic Cut

Not impressed with this slide, initially. As others have mentioned, don't expect to mount your red dot without an additional email to ATA customer service. My slide is cut for a Vortex Venom and the supplied screws aren't even close....
Additionally, this slide changes the feel of the trigger. I have an APEX kit installed on my Glock 19 Gen 4 and it's smooth as butter with the factory slide. When I move the kit's plunger and plunger spring over to the ATA slide, the trigger grit returns as well as a noticeable increase in the trigger pull....the two exact things I was trying to IMPROVE with the Apex kit!!!

This slide is natively compatible with a Gen 3, but accommodates Gen 4 frames with a Gen 3 parts kit and recoil spring. I have a feeling this mismatch might be the reason for the trigger feel.