Well, you’re right in the normal sense. I own quite a few of them.
However, there are rounds and calibers out there that have the equivalent delivered energy. Additionally, there are other slug designs anywhere from copper jacketed HP compressed powder to newer solid copper designs that open up like a grappling hook on impact.
I don’t think they’re gonna end up with a 45 auto cartridge because of size/weight and magazine sizes. If I had to guess, I’d say they’re gonna go with a .40 SW or maybe even a more exotic design something like a FN 5.7mm.
But, they could well end up surprising us all. Ain’t no telling with acquisition weenies.
It should be noted that Major Nidal Hassan, of Fort Hood Massacre infamy, brought down two charging soldiers with single COM shots using the 5.7mm.