I stopped at a gas station to get some smokes and a soda and it struck me to ask if they had any laser pointers ('Murica Fuck Yeah). The little Chinese impulse-buy $2 variety.
They did! So I taped the little disposable laser to my slide and have been using it to get a visual on what happens when I pull the trigger. I'm fine with 85% of the trigger, but on that last little bit that causes the break, the gun barrel bobs down exactly the amount you'd expect based on target I posted above.
It is because the break, while smooth and easy to feel, needs a comparably far greater amount of pressure to accomplish. Building that pressure does not throw my sighting off, but immediately after the break there is overtravel with no resistance. So I pull through the stiff section, it clicks, my finger quickly accelerates, and there is something in my grip that causes the gun to move forward a tiny bit in my hands. Firing slowly DOES make it happen more severely.
Totally adds up...this is why the other gun I've been shooting has gotten worse, too. Or rather, I've gotten worse with it. It's got SA with a little smooth takeup and a decently stiff pull, so it's not so much a difference in effort as it is that this trigger has no discernible feel of overtravel. Just snaps and I'm at the end of the trigger.