I'm still struggling with rapid fire, I'm deadly out to 30 yards with my 9mm (can put them all in a 3 inch bullseye) slow fire but rapid fire is another thing...
150 rounds
View attachment 861235
There are a few possibilities for what is being seen here. Taking you at your word that this
only happens in rapid fire lets us narrow the range of probable explanations. In order of likelihood, with the first more likely than the second, and the first two
far more likely than the third:
POSSIBILITY #1: In an attempt to get the gun back on target faster, you are "muscling" it with your right hand and mistiming the input. You are trying to actively counter the recoil before the recoil begins. This is
extremely common. This often comes along with a flinch in slow fire. The fact that it is only showing up in rapid fire means this is probably
not a true blink-involved flinch, but just an improper understanding of recoil control with handguns.
If this is the problem, a correct understanding (and then application) of handgun recoil control is the answer. First, understand that the way to control recoil is not primarily through the input of counteractive forces, but through continuously exerting
neutral control. What does that mean?
Think about walking a dog that is not well leash-trained. Or holding the hand of an unruly 5 year old as you walk through the toy aisle of the grocery store. They may pull left, they may pull right, they may go forwards or backwards. You can either end up jerking the leash or the kid's hand in a series of small tug-of-war contests. Both you and the dog or child will not move in a straight line... it will be miserable.
However, if you are significantly stronger than the dog or the child, then you could just focus on holding your hand in a fixed position relative to your body as you walk. Rather than actively jerking the kid or dog around, you simply hold your point of control static. You don't let the dog move the handle of the leash... it stays next to your right hip, if that's where your hand is supposed to be. Your hand may oscilate a little as the dog or kid bounces around, but you are
not going to let them move you or your hand's position in space. You have positive,
neutral control. No matter which direction they apply force in, your hand and arm muscles are already engaged, locked in place, and not going to allow much movement to occur.
That's what you want for your grip on the gun. You're not going to let the frame move vertically in recoil and then push it back down.
You're not going to try to precisely time a big push down. You're going to hold your hands still in space. The gun will oscilate, but the sights will come back on their own when the slide closes.
That's the attitude/concept you want.
Second, in order to make this happen, you do need to apply a substantial amount of that continuous neutral force to the gun with your left hand. You need to get your left hand in a position of leverage, and you need it to stay
stuck to the gun frame in a fixed relationship. If you have to re-grip the gun after a shot, you have lost grip and your left hand did
nothing for you. Because the left hand's relationship to the gun is a "friction fit," rather than "interference fit," you will need to squeeze
hard. Hard enough that, when you take your left hand away from the gun, the imprint of any checkering on the left side of the gun should be visible in your left palm's heel for a few seconds.
POSSIBILITY #2: The gun is firing, recoiling, and then returning
past the target, and you're timing the shot to coincide with the "dip" at the slide's close. Watch a slo-motion video of a semi-auto pistol...
most of the movement of the frame actually comes at the times when the slide slams into it at the rear of its travel (produces a muzzle-flip), and then again when the slide comes home (produces a muzzle dip). It is
possible that you are triggering the shot during that dip. The fact that the group/tendency is towards the lower
left makes this substantially less likely than the first possibility, but, if you don't have anything like enough left-hand grip force, it's possible.
Three possible solutions if this is the case. First, improve your grip so that the total range of motion of the gun is reduced (see above). Second, start having awareness of sights throughout the recoil arc, including the dip at the end. You can't just see the sights on the target at the time you decide to fire... you have to maintain awareness
through ignition, and then throughout recovery to the next shot.
Once you're able to see the sights moving through this arc, you should be able to know when you can or cannot trigger the shot. If your gun (even after you've done everything you can do with your current level of grip strength) has a lot of dip, then you probably have to wait out the dip to fire the next shot.... or change the gun's setup to reduce the dip. Competitors in speed shooting games typically tune their recoil spring so that the return of the gun is as neutral as possible.
Most handguns come oversprung on the recoil spring for optimal speed shooting. Stiff springs can help with reliability with full-power ammo feeding, and many manufacturers assume that users won't ever actually change a recoil spring, so they think it's better to start off with a lot of "extra" spring so there's still enough spring force left to close the slide even after 20k rounds.
If you're willing to take more responsibility/control over your gun's setup and how it relates to your ammo, you can play around with lighter springs to reduce the closing dip.
POSSIBILITY #3: I think this is unlikely to be the real cause, but it's possible that your grip naturally points the gun low-and-left, and that, during slow-fire, you are manually aiming the gun correctly, but it is "returning" to a more "natural" position during rapid fire. Since I think people are actually able to adjust their index (place the gun points without conscious effort) pretty easily, I doubt this is the issue, but you could play around with your right hand's placement on the gun (rotationally mainly). Low odds proposition here. I hesitate to even mention it.
ETA: There's also a chance that you've got a finger placement on the trigger that is causing a bunch of lateral input, but the fact that you're not having these issues at all in slowfire makes me doubt this is the issue.
But if you're not happy with that level of accuracy, slow down and only fire as fast as you can hit within the area you are aiming at. 
