It's amazing that for years 6 shot revolvers, 8 shot 1911's, and so on were able to get the job done, but with the introduction of 17+ rd handguns they are suddenly not enough.
I carried both of them then, simply because thats all there was. Once things started to change, and the autos made more and more sense, the capacity started to go up, and the realization that the .45 wasnt the Sword of Todd, as was the order of the day at the time (that, and the 1911's were getting fiddly and annoying), I moved on and never really looked back.
I still shoot 1911's, and 5, 6, and 7 shot revolvers on a regular basis, and while they shoot fine, the one thing that clearly stands out is, they run empty way to quick, especially with multiple target drills.
If the guns are all about the same size, and the rounds all pretty much work the same, seems like a no brainer to me to go with the hi cap.
The LEO was firing so fast that he put four more rounds in the perp before the perp hit the ground.....four more than were needed to stop the perp.
We have no idea as to how many were actually needed, simply that it was basically over by 9. The last three were just anchor shots that cinched things.
He was still on his feet and moving after round 4 too by the way, albeit, moving away. He didnt go down until 8 or 9.
Maybe the "old timers" had something with the double-tap strategy. If two rounds don't stop the perp, aim at something else and fire two more. If it works, stop shooting and save ammo for the next threat. One trainer ('80's or '90's, IIRC) set up a cardboard target with a balloon or explosive charge on the back where the shooter couldn't see it. The shooter's job was to double- tap in different areas until the balloon/charge was hit. A lot of students wasted a lot of ammo using the "shoot them to the ground" strategy.
If you shoot reactive targets that go down with "proper" hits, shoot them to the ground works quite nicely. If those balloons or charges were in the right places (anatomically), the results would likely be the same, and even quicker, as if you start COM with your shooting, youre normally moving right up to the head (and all points in between), with no hesitation "to see" how youre doing. You shoot, and keep shooting, until the target is down and out. You dont waste time trying to figure out why they arent.