That is the science behind it, but making it easier for the manufacturer doesn't even need to go nearly that far. All we have to do is take
all the most popular handgun rounds and look and see which use a large pistol primer and which use a small.
.45 is the only high volume, highly popular and ultra-high production and sales handgun ammo that uses the large primer. 10mm, .41 and .44 Magnum, .45 Colt? In factory ammo, you could add those four up and triple it and it wouldn't even approach 9mm. To say nothing about .380, .38 Special, .357 Mag, .40 S&W, etc etc.
Even if the non-toxic primers had never come to be whatsoever, it is an extremely good deal for the manufacturers to move from a large pistol primer in .45 to a small pistol primer.
What truly stinks for the end handloader is the *gulp*
CENTURY of stockpiled, used, wonderful, and perfectly functional .45 brass we've always had.
Believe me when I say that if you *HATE* small primer .45 Auto brass... brother, I hear you and I understand, absolutely.
But I will also say this, and with no apologies: it's a little bit of vindication for those of us who have always taken the time and care to inspect and separate our brass. This problem with primer sizes in .45 doesn't slow me down even a half a blip.
Sorting and inspecting brass is a little boring and monotonous at times, but for me,
it has always been a very necessary part of the process and it hasn't changed my world in the slightest, save for the extra couple of containers I now use to store a different headstamp of .45 brass.