I was just trying to get back to OP question. We all know Shot placement is key but not everyone is a expert shot. I was just trying to say whichever has more ft lbs of energy is my choice.
Not that I disagree with your intent, but I think ignoring the OP's question and focusing solely on shot placement is proper because it does actually answer the question - the answer being, bullet grain doesn't matter. (to a point mind you) The repeated statements of shot placement, shot placement, shot placement are the correct answers to the question.
What kind of ammunition allows you to shoot the most to GAIN the necessary skills so that you BECOME an expert shot? 10 times out of 10, the answer will likely be 9mm. If a person is willing to spend the money to reload .45, then they will be able to shoot more rounds of .45 than factory 9mm. Then again, if a person reloads, they could reload 9mm for less and end up shooting more, thereby becoming even better trained. If you are an expert shot, then .45 might not be hindering you. If you aren't an uber-awesome marksman, 9mm is probably the better option.
Shot placement is king. Making accurate shots with a 9mm trumps near hits with a .45. What is the best way to make accurate shots? Practice. And lots of it. Thousands and thousands of rounds fired in practice and training. Since we live in a world of limited resources and finite incomes, the skills necessary to save your life are more likely to be learned, dollar for dollar, with a 9mm.
So since shot placement is king - which caliber best gets you there? 9mm. for those in LE where ammo is supplied, obviously this issue isn't as important.)
Try out this scenario: 8 drug crazed ex-Marines with ptsd and razor sharp K-Bars (or other similar bad dudes) are outside your bedroom door. They will come in through the door and try to take your head off in two second increments. You have a choice between two handguns, lets say a 9mm (velocity) and a .45 (mass) both loaded with 8 rounds. You have practiced with both and shoot each equally well. You choose.
...FOR ME, mass wins this one easily.
As stated by Koshinn, you don't have 8 rounds and 8 rounds. You have 8-9 vs 18. With that capacity increase, along with the improved skills you have because you regularly train and shoot twice as much with that 9mm, I will take the 9mm every single time.
I reckon if someone was shooting at me from, say, 25 yards, I'd rather get hit with a 9mm FMJ than a .45 FMJ. It would be like the difference between getting hit with a baseball or a bowling ball.
Far from it. The difference would be negligible. You are talking about roughly a 2mm difference. All handgun rounds are severely anemic to rifle rounds, and none are "manstoppers" unless the bullet hits something important. The terminal differences between a 230gr .45 and a 147gr 9mm with modern HP ammo is negligible. Same basic penetration levels and same basic expansion levels. Getting shot is getting shot, and unless it is a CNS or vital organ shot - the mindset of the individual who is shot is the most determining factor of the affect the bullet has on them.
The biggest difference that caliber and weight choices generally influence are intermediate barrier penetration. If you think you'l encounter situations requiring you to shoot through auto glass, a .45 or .40 is going to be better than a 9mm. Intermediate barrier penetration makes a difference when you are in LE - much less so as a civilian carrying a weapon for self defense.
What kills? My mother in law's meat loaf and her chicken and dumplings.
As to the post ... training. The only thing that matters is being able to place shots(whether it is a 9mm, a .357, a .40 S&W, a .44SP or a .45ACP) on target when it counts.
This. +100. Being able to place shots on target when it counts is the only thing that matters. That ability requires training. And training is cheapest with 9mm.
Clearly, some shoot significantly better with a high end 1911. And maybe, but not likely, that is the best choice for those few individuals. But I would bet a year's worth of ammo that that same shooter would gain better skills and be a better shooter in one year of training and shooting 9mm in one steady platform than doing anything else.