I'd also suggest that the 3/4" groups is a red herring as well.
The reality is that 99.999% of the population is incapable of holding these kind of groups at 10 or even 6m with a pre-charged pistol let alone a spring one unless rested at which point even a Tempest will get a look in...

Yes, the 45 is easier to shoot more accurately in general terms, but its also a lot bigger, it was a lot more expensive at the time and I sold both my 45's long before I was forced to let go of Magnum.