Did you try the random empty cases in your revolver to check for a flinch? My first handgun groups were truly god-awful too. This coming from a background of rifles and archery. The cause was a chronic flinch. I didn't feel the flinch when shooting, and it wouldn't be there when dry-firing, but when I used the revolver technique, I detected it quickly. My hands would move downwards and to the left to try to counter the recoil. Groups looked like yours. Live practice was the only thing that helped. I dry-fired constantly, but it didn't help that much. My technique was perfect during dry firing, but would relapse into a flinch while doing live fire. When I was aware of it, I tried to control it, but using the same technique, I could tell I still had a significant flinch. Although I didn't feel it, and actually shooting wasn't unpleasant for me, apparently I was recoil sensitive with handguns. So I reduced recoil. I had an enormous 51 ounce ported .357 revolver, stuck a scope and mount onto it, and shot .38's out of it. It was probably weighing somewhere between 70-85 ounces, ported, and shooting shooting mild .38's. My first 5 shot group at 30 feet was under an inch. Moved onto shooting .357s, and got the hang of that. The key was learning to keep my grip consistent in pressure and hold, and not to fight the recoil. As the trigger breaks, my focus went to my grip and following through.