Snap caps are part of my training! I made enough progress on trigger pulls on my rifles using snap caps, that I got some for my .40 a few months ago. I'm not sure if it's helped w/ the trigger control, but I know it's helped with draw-engage practice.

Of course, some of my practice has been w/ rimfires ... and the warnings against dry-firing are stronger w/ them. Between my 10/22 and my "1873 SA" knockoff, my .22 caps are about worn out!