Lets for the sake of argument say that the difference in effects on soft targets of the .357 and .45 is a wash.
Now lets look at the other benefits and disadvantages of both cartridges:
--------------.357sig------.45acp
penetration -----13"---------13"---------------- Both are acceptable.
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Mag capacity---15/17 -------13------------------Full size glock mags.
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Recoil--------.357 sig has similar recoil force, but is faster than .45. Both are less than .40
------------- (according to all data I can find online)
................................formula for momentum applies here (M*V, 124gr*1450fps = 25.9lbs, 230gr *900fps = 26.3lbs, 165gr* 1150fps = 27.1lbs)
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Intermediate barrier penetration:
---------------- .357 sig known to penetrate level II vests, and car doors effectively, with energy left over to neutralize target on other side.
-------------------------------------.45 stopped by level IIA body armor. (lowest NIJ level) (
http://www.justnet.org/pages/BallisticCPL.aspx)
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Cost:--------$23.50 per50,-----$17.50 per 50 -------------(bulkammo.com)
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special features:----.357 barrel interchangeable with .40 s&w barrels allowing for cheaper practice rounds and ability to be suppressed more effectively.
-------------------------------.45 is subsonic allowing for a more effectively suppressed round.
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Range:--------------because the .357 much faster than the .45, its parabolic curve is much straighter and you can shoot effectively at much larger distance of the .45's effective range. That is assuming the shooters marksmanship ability is at that level.
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Negatives:---------.357 is a LOUD round compared to .45
------------------------------ .45s are physically heavy compared to .357
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My conclusion: Both rounds, being the same effectiveness on soft targets, have advantages and dis advantages. If you want to go with the .45, it's a fine choice. I will not give anyone a hard time for choosing it. It has been proven for over 100 years. It has advantages over the .357 that are useful. However, the .357 sig, based on the .357 magnum round, has also been proven. the Auto is a new technology, but its benefits are clear. The ability to carry a larger capacity of rounds, it intermediate barrier penetration, and the ability to swap barrels to use another caliber entirely make this round an excellent choice as well. To say that it is ineffective compared to a .45, or even in the same league as a 9mm Parabellum is a false statement. If you don't like the round, for some personal reason, don't get it. But if someone chooses it, don't try to convince them they are wrong because you will get into a long roundabout argument that will go nowhere fast, and the result will be that both of you hate eachother over something as petty as caliber choice.
I think the most important thing, ( AND MY NUMBER ONE POINT for starting this thread) is that each person is comfortable and confident in their chosen weapon system. No one should have any delusions about what they are doing. No pistol round is a guaranteed 1 shot stop, nor is any pistol round plainly ineffective. practice what you think works for you. And remember that any bullet can kill YOU.