I had an Olympic .45 years ago. Pretty much proprietary, nothing like what is available today.
All I remember is it took really expensive mags and kicked like a mule. I thought about revisiting it with modern solutions but I already scratched that itch and would rather have other stuff.
.45 ACP is a round that does NOT benefit from a longer (16"+) barrel. Whatever the barrel length is on the Thompson is where max velocity is obtained. I think it is around 10" so on target there.
There are two dildos in that photo. One is a killer dildo.