Usual great information...
The 45 Super was built around the 45 acp chambering and you basically have to rebuild your 1911/insert gun name here...to use the round. It mimics the ballistics of a 44 mag in your semi auto.....a great idea but IMO, didnt do well...because of the great lengths you have to go to, to use the chambering, in regards to changing your gun around.......
1. Firing .45 Super from a .45 ACP gun doesn't require any modification. That's the WHOLE POINT of the cartridge... use heavier recoil springs and you are in business. Same with .450 SMC, which is essentially the same (different brass & primer type).
2. .45 Super ballistics and .44 Magnum ballistics are nowhere near each other. .45 Super tops out at 230gr @ 1,200 ft/sec from a 6" barrel. .44 Magnum will launch a 330gr bullet over 1,300 ft/sec. .460 Rowland will get you closer (and WILL require a different barrel, etc. to use).
3. .400 Cor-Bon is, ultimately, a pretty lame-o cartridge. Its ballistics are inferior to 10mm Auto (Cor-Bon's own 10mm hunting loads smoke anything in .400 Cor-Bon), you can't really use bullets over 165 grains (vs. 220 for 10mm), it is unreliable from double-stack mags (so much for that Glock 21...), and you give up capacity compared to 10mm to boot.
4. .40 Super puts up more serious numbers, at least with the lighter bullets... 1,800 ft/sec with 135gr bullets and 1,500 ft/sec with 165gr bullets. With heavier bullets, its ballistic advantage over 10mm is pretty small (200gr @ 1,300 ft/sec vs 1,200 ft/sec for Cor-Bon's 10mm "Penetrator" load).