Originally Posted by Florida_Vet
The reaction of shooting at something that is one or seconds away from killing you cannot be duplicated at a range. Short and sweet: if you are comparing between 10mm and .45ACP. I'd go with the gun that you are totally and instinctively comfortable with, that you can load, fire, rack, clear and disassemble in pitch black darkness. The gun you can use as easily as your toothbrush or car key is the one to go with, given that your range of caliber choices is as you describe.
This is the iron truth. People change guns all the time in this day and age, often based on a magazine article or internet posting. They often convince themselves that they have 'improved their odds'. The value of familiarity with a weapon and natural, instinctive presentation on-target cannot be overstated.
“Nine-tenths of tactics are certain, and taught in books: but the irrational tenth is like the kingfisher flashing across the pool, and that is the test of generals. It can only be ensured by instinct, sharpened by thought practicing the stroke so often that at the crisis it is as natural as a reflex.” ~ T. E. Lawrence