The 9mm was born as a high pressure cartridge and does its best work with bullets in the 115-125 grain range. When you put 147 grain bullets in 9mm casings, you turn it into a rimless 38 Special (not that the 38 Special is a bad cartridge - it is not!)
I'll dispute that. And so will the people whose profession is terminal ballistics, and who look at more police shooting reports and autopsy reports in a week than most police agencies will in a year. Ditto for gun writer pundits. Dr. Fackler (passed away a couple of years ago), Dr. Roberts, etc and others have been in the terminal ballistics profession concerning service ammunition and it's development for roughly four decades. Roberts, as one, still is involved the last I heard.
147 gr service ammunition from Federal, Speer, Winchester, etc turns in similar results as other 9mm bullet weights, whether standard pressure loadings or +P. It isn't in the slightest bit handicapped by not being in the 115-125 gr. range. There are multiple reasons for that: developments in propellant powders, engineering of bullet designs, etc.
The 38 Special +P can do far better work than it is often credited for. I think it gets unfairly compared to the .357 Magnum and people look down upon the 38 Special as "it's just a 38 Special". This is an unfair view.
But wait... if the 9mm originated as a high pressure cartridge with the specific weights you mentioned, then surely we have to also remember that the .38 Spl didn't originate with those +P loads. It was something like a 158 gr. round nose doing about 880 fps out of a 6" barrel, wasn't it? If we are to stick with original loadings, then we should be also sticking with the 158 gr. round nose in the .38 Spl.
A 9mm 125grain jacketed HP travelling in the neighborhood of 1200 fps is no joke.
A 158 gr 38 Special LSWCHP driven at +P velocities is no joke.
Given the right load, both of those cartridges are more than capable.
Now we're on the same page in agreement. Just add the 147 gr (and the new 135 gr) service ammunition from Federal, Winchester, etc and we're about right. I believe that is currently an established real world fact from the ammunition development/LE world, not just an opinion.
For decades, the 9mm Luger cartridge suffered from the "It's not American" syndrome and the 38 Special suffered from the "it's not a magnum" syndrome.
Still do.
The .38 Spl. also suffers from one other thing: after being abandoned by police agencies, there's minimal time and money put into the continued R&D for .38 Spl. service/self defense ammunition for sale to the public.
The number of people that choose a resolver for self defense, whether a snubby or something bigger, is completely dwarfed by the LE agency and civilian markets in the auto pistol service calibers. As a result, modern .38 Spl ammunition is not at the performance level it would be by now if it were still among the service calibers being used by LE agencies. The allotment of R&D time and money to various calibers leaves the .38 Spl. mostly neglected, sucking the hind tit.
And in the same vein, 9mm is making the greatest technological gains, versus .45 ACP, .357 SIG, and.40 S&W, simply because LE agencies issuing 9mm have become the vast majority of that market. So that's where the majority of the potential service ammunition market profit is for Federal, Speer, etc. And so, they devote proportionately greater R&D time and expenses to 9mm, compared to that which they allot to the other calibers.
That's not an assumption on my part; that's from both the head engineers at several of those companies and from Dr. Gary Roberts, after working with both the federal government as well as individual police agencies and ammunition manufacturers. It logically makes sense to me that would have an effect on the amount of advancement in performance service ammunition will have among the calibers as you look at your choices in service/self defense ammunition sitting on the store shelves for sale to the public.
I carry 9mms by choice: that's with assorted flavors of .40 S&W, .38 Spl. and .357 Magnum, and 10mm to choose from. I've been carrying HST 147 standard pressure ammunition for years now after some of our Close Protection guys were sent to one of ATK's ballistics seminars where they were able to watch and shoot at pretty much anything with anything resembling service ammunition, and brought the results of all that back. As of today, perhaps there's now something in 9mm service ammunition that is now measurably better. For now I'm happy assuming any improvements in 9mm in the last few years are pretty minuscule if anything, and I'm no worse off continuing with what I'm currently using.
However, if somebody told me I was restricted to using .38 Spl LSWCHP ammunition for the rest of my life, I would not lose one minute of sleep or suddenly feel inadequately equipped for Bad Guys Happening. If you're using some sort of service ammunition, performance differences are a tiny percentage of the issues involved.