CDW4ME, gelatin doesn't wear varying thicknesses/types of clothes or have bones....
The gelatin is good for a standardized testing medium but does not/cannot take into account different sized people or what they may have on...
........................................................................................................
You can never tell what type or types of things that your defensive round may have to go thru to get to something vital in the bad guy to stop the attack....45 FMJ is about as good as it gets for all things considered. Nothing wrong with a HP except that it cannot be counted on to expand in all situations and, as was said, a .45 doesn't shrink.
I'd also feel just as confident using a 180 FMJ in .40 or a 147 FMJ in 9mm, or even a 158 SWC in .38 as I would any of those with HP ammo...why, because whether or not the ammo expands will have little impact on it's stopping capability compared to where it goes - shot placement with adequate penetration is what makes a difference...larger bullets that are able to break or shatter bone helps too!
Not saying HP ammo isn't good to have, a premium manufactured round of ammo suppose to have better quality control and powders and sealants than the lower cost line of "target" ammo...but most manufacturers also produce a premium FMJ round as well...but probably sell few of them due to the cost being pretty much the same as the "defensive" line of ammunition - that's advertised to be so protective and efficient...
Do I feel confident using Winchester Ranger T (or fill in the blank with whatever hp ammo has proven functionable and accurate in my pistol) ammunition?? Yep, but I'm just as confident in the "target" ammunition that I've loaded for myself! .... Do I count on the Ranger (or whatever) ammo to expand to be effective?? Nope, the shot placement with enough penetration will determine that. Expansion is a welcomed bonus but cannot be counted on.
Overpenetration of standard .45 FMJ ammunition is way overblown and is largely just thought to be more of a problem than it actually is .. largely due to smaller FMJs in faster calibers (115 and 124 9mm mostly) having been seen more often to be excessively penetrative.....not that they always are, but that it has been observed more...it will always depend on factors that you can never forsee whether or not a FMJ of handgun caliber will or won't penetrate on a solid shot....HP ammo has been known to "overpenetrate" as well ... you cannot believe that since your bullet has a hollow point that it will expand perfectly and magically stop just shy of exiting whatever size of bad guy that you just shot - that would be great, but in the real world, there is no absolutes...you can get "probablilities" or "maybes" with differently designed ammo in different weights and speeds but no absolutes are out there...
Yep, all things considered as much as they can be, a standard .45 FMJ is just about as "ideal" as can be expected...
Know your field of fire as best you can, shoot straight and hope for the best...