I think a big reason why many trainers in the seventies and eighties were teaching the palm smack and getting away from the thumb press was the shift to .357 Magnum.
Makes sense. The Achilles heel of the FBI reload is the possibility of a stuck case, and IME, that possibility goes up
greatly when one goes from .38spl to .357mags.
I was looking for some speedier reloading technique on Youtube the other night and happened across a Matt Griffin video.
He is also left handed and uses his right index finger to operate the ejection rod. In the video, his reload (shot-to-shot) was 1.37 secs...I'm pretty happy when I can break 3 secs
Matt is a top USPSA shooter (who, IIRC, came within a whisker of dethroning Jerry Miculek for a national title), and was likely using moonclips, so his reloads are gonna be smokin'. Also, I'm not sure I saw the same vid, but those I saw were during dry fire, where he's trying to beat a par timer rather than land 2 good live-fire hits.
Using speedloaders in match conditions (i.e. in IDPA, using a cover garment and reloading from cover), a consistent 3 seconds is a good benchmark (
if the shots before and after were good hits). In dry fire practice, that translates into about 2.6-2.7 seconds, btw. Getting a bit faster is icing, but that takes a ton of practice, and in the meantime, definitely not worth it in a match if you're flubbing some of them by rushing.
For everyday carry, I'd agree that 5 seconds seems like a reasonable benchmark. Maybe even a bit more if you have to dig in your pocket for the loader.