The .40 is a bit more powerful, at the expense of sharper recoil, greater wear and tear (most .40 handguns on the market are simply overbored 9mm's), and slightly lower magazine capacity. For me, the trade-off has never been worth it and I quickly sold off the two .40 handguns I once had.
You can shoot a Glock 17/19 or HK USP, or a large steel-framed pistol like a 9mm 1911 all day long with +P ammo and never worry. With alloy-framed 9mms (Beretta 92, S&W 39/59), ultra-compacts (Kahr P9/PM9, Kel-Tek) or thin steel weapons (Hi-Power) I'd advise against a steady diet of +P ammunition. Fire a few boxes through it to check functioning then use standard-pressure ammo for most of your range time. But the big steel and polymer 9mm pistols are almost indestructible by comparison.
Depends on what the intended purpose is. What are you looking to do with it and in what sized package? Do you intend to reload? ect.
If you give us more info we could probably point out some more pros and cons for you.
I own both and my .40 is my favorite game gun.IDPA ESP class
9mm browning is also a fun gun to shoot but iprefer the 1911.
I'm going to use it as my carry weapon. Right now I'm carrying a commander length 1911 and I just don't shoot it as well as I shoot my Hi Power. I'm in no way planning on reloading. Every 40 that I've shot, I shoot well, I just don't like how snappy the round is. I figure if my follow up shots are faster and more accurate, that's what's important.
I personally don't think that there is all that much difference between the .40 and .45 loads, maybe on paper but when shot with one I really don't think that someone is going to say, well I'm glad that he only shot me with a 200gr 40 S&W! that 230gr .45 would have been much worse! I think I will get up and ask for another of those 40's due to he is alittle under powered with the .40 cal today.
If your that concerned I'd suggest the 500 S&W! There will be nodoubt then.
That thing is a friggin hand-cannon, literally. Last time I was at the local indoor range some guy had one in the far end, which is actually on the other side of a closed door. If somebody overthere is popping off with .45 ACP you can hear fain pops. Well, all a sudden I hear a solid BOOM like some clown is shooting a 1911 over my head or something. I look around, nobody. Check the other side of the door, that guy had about half a dozen range groupies taking turns with the beast.
EDIT: I'm talking about the 500 Magnum, of course. 600 Mag would be scary, I think I'd rather chop a Barrett .50 BMG down to pistol size, lol. Isn't there a law that says no civilian use rifled barrell can be over .5 inches in diameter anyway? Maybe they could make it a "shotgun pistol" and offer slugs for it. Accuracy would suck, but who's going to actually use it for anything other than screwing off anyway? :dope:
I owned a P226 for a very brief time a couple of years ago. The thing handled and shot like a Cadillac. The only reason why I sold it off so quickly was because I suddenly found myself cash-strapped, and to let go of one of my nearly two-dozen cherished 1911's instead was too much to bear. :dope: