Personally, I think you are going the wrong way. Until you can shoot little tiny groups and shoot multiple magazines full of cartridges on a small target at 20 yds then you are fixated too much on caliber and you need to practice your shooting. Once you can hit where you are shooting without fail, it won't matter so much what caliber you are using.
As far as shooting is concerned, I am equally good with the Wonder 9 or One-Shot Dropper .45.. LOL.. Actually the 9mm is a bit tougher to shoot, because I always have to think a bit more what I am doing, since the gun tends to snap a bit. Once I get the mind control correct, I am shooting tight groups with that Sig. However, with the .45, I point, aim and hit. I am a glutton for punishment and dont mind the loud explosion and pressure it puts on my hand. Even, I love shooting it one handed for more fun
. I think in a stressful situaiton, I have a lot easier time hitting the target with the .45..
As far as the guy who says the 9mm is better for taking out a group, I like to see some evidence of that. First of all, what good is the extra 5-9 rounds of my 9mm versus a .45 if I am nervous and I hit the guy 4 times and he still is coming after me. If I flatten the guy on round 1, most likely the other guys won't want to be next. I just don't see how you will have time to unload 19 rounds on a group of guys anyway, if you are getting jumped. If they are far enough away, I would think you would then easily have time to reload ur mags or dump in a speed loader even.
Anyhow, this discussion has penetrated the deepest dimensions of my mind and I am pondering if I should keep the SIg 9mm or go all out with .45. I have also considered the .357, 10mm and .44 route to the .45, but seeing that I have a .45 and lot of .45 ammo, I would like to consolidate my .45 stash and not have to worry about maintaining to differnet types of guns and ammo. Some say buy two S&W M&Ps , well I rahter not.. I just really think the H&K 45 is very snazzy, fits like a glove in my hand and I am in love with it; I will pursue it if I get rid of my Sig. I do plan on getting a .44 for my backwoods hiking this summer and was also thinking of getting rid of the 9mm to fund this purchase, money is tight.
One reason I may keep my 9 is that I got a lot of ammo for it and seeing how hard and expensive it is to get ammo right now, maybe it be more rational to keep it. The price I paid for my .45 ammo two months ago has gone up considerably and almost nobody I can find even sells .45 or 9mm ammo anymore
.