Most of my shooting over the last couple of years has been slow fire. Deliberate, aimed fire with (ideally) an almost Zen-like focus on slow, "surprise break" trigger squeeze. I'm passable at this - not great, but passable, as you can see from this target shot last October (with Burt's XD).
For me, slow fire is several seconds between shots. Rapid fire is a shot at least every second (actually this is slow compared to some of the folks I've shot with). This time, I was trying for two shots a second, and my groupings were, well, more interesting:
All over the map. Some not even on the map. 60 rounds, 44 hits (74% on the paper). Boy, howdy, this was a quick (fire) lesson in humility.
Target Re-acquisition is my biggest challenge: unless you're shooting .22 or something with almost no recoil, each shot will move your aim point off-target. Lining the target up in your sights lets you not miss the target (duh!). Doing this in slow fire is no problem - take your time, get lined up. For rapid fire, you need more "muscle memory" than I have developed. I need to spend many more hours under the Jeff Cooper Mind Enhancer Ray and then go practice, practice, practice.
Slow fire is terrific fun - groupings are small and tight, and it's easy to congratulate yourself on your excellent marksmanship. I typically step back from the line in a relaxed, Zen-master state.
Rapid Fire is work. It's hard, it's frustrating watching your groupings balloon to the size of a barn. You step back from the line tense, and even sweating. You see your mistakes in the harsh spotlight. But this seems to be the way to better marksmanship.
A consciousness of wrongdoing is the first step to salvation…you have to catch yourself doing it before you can correct it.- Seneca