This isn't a "High Road" Politically Correct answer. If you cannot handle it, move on.
The OP and a few others, including me, are asking for comments and sharing their experiences with the G19. Why assume and assert that we're all un-trained, lousy shots?
Several people have stated, in their own words, that they are lousy shots.
They may be decent shooters with one particular platform, but their skill level is such that they do not have the mental and/or physical understanding of a variety of guns. This tells me their skills are lacking in one or more of the fundamental areas of handgun shooting.
So, again, we're back to the failure of the shooter to understand and use the gun as intended. Competition guns are not combat guns. (I'm defining a competition gun as one expressly built for that purpose, which includes heavily modified combat guns). The Glock is a combat handgun that happens to be used in some "combat" competition games (and not the other way around, though some argument could be made about the 17L, 34, and 35 models).
Why can't people figure this out? It's just not that hard. If you want tiny groups, use the correct
competition tool
created for that purpose. I certainly wouldn't take my Glock 21 and an Advantage Arms 22 Conversion kit to an NRA Bullseye Competition. Additionally, don't take your competition gun to a fight.
How can someone be considered a master in handgunnery if they cannot use
any handgun well? Specifically, "action handgun" implies some sort of loosely combat oriented discipline. You should be able to pick up any handgun and do well with it. If you cannot get a 2-4 inch group with a Glock, SIG, S&W revolver, Kel Tec (or any other gun), then you have some "fundamentals" work to do. Dependence upon a particular trigger or other gadget just means you're a trying to purchase a better score ("gaming"). But, to say you cannot shoot it well simply due to one or two factors reeks of incompetence (from previous posters' words, not mine) based upon a lack of practice and forethought about handgunning.
My old "shootin' towel" listed a whole bunch of shooting excuses: "FARTED", "FLY on the front sight", "DRUNK", and so forth. That's all they are: excuses! I have seen it a hundred times, both in preparing for competition and defensive handgun training. When people start whining on forums like this, it's because they're refusing to admit their failure on the range.