I always wonder exactly what people mean about that. If I've got my strong hand up as high on the gun as I can go, it's not like my trigger finger is going to be perfectly in line with the barrel. My trigger finger is, in fact, pointing a few degrees down. As a sidenote from my 1911, you should see how far down I have to reach on my Redhawk! What is Jerry Miculek talking about when he says Square Trigger Finger pulled Straight Back?
So how can I "pull it straight to the rear"? Maybe I'm being nitpicky here, but hey, grips and trigger control are just nitpicky sons o' guns.
And back to the original topic, is it bad to exert strong grip with my SH Middle Finger?