I dunno....

I've fired many rounds with my Shield .45 with a one hand grip, either hand and such AND my weak hand is actually WEAK due to a spinal injury... and NEVER had a FTF . I can't MAKE the pistol fail, not even with shotshells and desert dirt. I haven't even needed to change mags or springs. Never even had a mag drop event. I DO make sure to solidly seat all rounds to the rear of the mag well.

I hear ya, but just don't understand how this happens with this pistol unless the grip style being used is somehow interfering with the slide / lock mechanisms ? I just dunno... I would have given up after trying TWO of em . Too bad this model doesn't seem to suit you, I've found it to be my all time favorite EDC .