I have a Hipoint 9mm and you are correct that it is accurate out to 100m.we were at the range yesterday and hitting a 9” steel plate at 100m consistently. The only problem is some feed issues.
Last time I checked the deadliest round used in gunfights was the Remington .357 Magnum 125 gr. jacked Hollowpoint. It had a rating of 97% letheality on two legged varmints. Extensive records are kept on these matters.
My personal business load is .44 Special 210 gr. jacketed hollowpoint @ 1300 fps. I have them professionally loaded. Preferred pistol is a 5” pre- model 24 Smith & Wesson (4th model hand ejector). A fairly stout but controllable load. It will regularly put five out of six into a 5 gallon pail at two hundred yards. Admittedly this is just messing around. You have to have all of the front sight above the rear plus about another four to six inches of elevation to get on. I never use it at that range though. I have a similar load in .45 Long Colt I use in a model 25 Smith with a six inch barrel. Bullet is a little heavier - hard wet 220 gr. w/ gascheck, velocity similar and I feel it’s pushing the Smith a little. It is definitely stout.
My oldest son is 6’3”, 225 lbs, and he loves that .44 load. He won’t touch the the .45, says it’s masochistic.