I am tempted to answer, "the difference is 0.05 inch." But I won't, because that would make me sound like a wise guy.

The .45 ACP is old-fashion, and delivers a relatively heavy, relatively slow-moving bullet. That's not a bad thing. It's just a statement of fact.
The .40 is much newer, and it delivers bullets which, although generally lighter, move somewhat faster.

I like the .45 ACP, and have used a gun in that caliber for most of my pistol-shooting life.
I have never owned a .40, but the FBI thinks that it's the bee's knees.

Really depends on what your firing out of... a polymer or metal frame handgun.

A poly .40 (lets say Glock) will be "snappy" comared to an all metal .45 (lets say Kimber).

I currently carry a Dept issued .40 Glock and feel it had more jump & recoil than my previous Dept's Sig Sauer .45acp.

This is my opinion based on my experience with them... all my personal handguns are .380 & 9mm. If I had a choice I would go .45 in a metal frame model.

For some of us, .40 is the bee's knees.........

Originally Posted by Steve M1911A1

I am tempted to answer, "the difference is 0.05 inch." But I won't, because that would make me sound like a wise guy.

The .45 ACP is old-fashion, and delivers a relatively heavy, relatively slow-moving bullet. That's not a bad thing. It's just a statement of fact.
The .40 is much newer, and it delivers bullets which, although generally lighter, move somewhat faster.

I like the .45 ACP, and have used a gun in that caliber for most of my pistol-shooting life.
I have never owned a .40, but the FBI thinks that it's the bee's knees.

.40 is the mall ninja,whiz bang and yuppie round
.45 is the back alley brawler, "git er done" type of round. USMC is going back to them.

Thanks for the replies...pretty much what I was looking for . I really do want one of each so I guess I'll go with the cheapest ( less expensive ) of the two and save up for the other while I get some up-close time with the first...thanks again .

Both are excellent choices for self defense calibers and you would do well to choose either. My personal preference is the .40S&W but I also own a few guns chambered for the venerable .45ACP, one of which I have carried. Best thing to do is to try candidate guns in both calibers to see which works best for you. Even though the .45ACP is over 100 years old, it is still considered one of the best SD calibers you can carry. On the .40S&W side, a well-known gun writer stated in one of his books that the Glock 23 is the finest combat handgun you can carry. While he tends to be quite opinionated, he gives and has his reasons for making this statement.

Hope you never have the experience of being shot by either.....

Originally Posted by Popeye7751

.40 is the mall ninja,whiz bang and yuppie round
.45 is the back alley brawler, "git er done" type of round. USMC is going back to them.

With people buying up all the ammo I would buy the one I could find ammo for. Both will serve you well in terms of stopping power.

Performance wise there isn't much difference at all.I prefer the 45,I find it nicer to shoot at high speed and it's an old popular round.Not so much a NATO round anymore but falls into that kind of classification-9,5.56,7.62x39,7.62x54(?) and 45acp will always be around to be had one way or another.

No real benefit of one over the other, other than personal preference.

That being the case, I have two .40's and four .45's.

Im thinking of a .40 cal due to cost of ammo. Unless your really into the .45 and/or a rich man, I think .40 is the way to go, and the way of the future. Just my 2 cents.

I'm either getting a Sig or a Glock in .40 cal in case you guys were wondering!

Originally Posted by berettabone

Hope you never have the experience of being shot by either.....

Me too!!!
They both have their place I just didn't care for the .40.. But the argument will go on forever.

At pistol ranges, both do about the same thing to the target. I like my SR40 better than the Colt 1911 I shot in the service. My Ruger is a double stack with 15 rounds. The 1911 had 7, It may be more the Ruger than the round. But the SR40 stays on target better than the 1911 did.

XD40 4" = 12+1

That is a lot of knock down power.

Originally Posted by XD40inAVL

XD40 4" = 12+1

That is a lot of knock down power.

That's what I'm thinking for my next purchase!

Originally Posted by paratrooper

No real benefit of one over the other, other than personal preference.

That being the case, I have two .40's and four .45's.

Agreed. I have one .40 and two .45's - love all three.

Originally Posted by XD40inAVL

XD40 4" = 12+1

That is a lot of knock down power.

A handgun bullet ain't gonna knock anyone down.

Strictly preference, for an experienced shooter.

I personally prefer the .45, because I prefer the more gentle recoil, but I have one .40 and it is a good shooter, too, and still quite manageable.

Originally Posted by XD40inAVL

XD40 4" = 12+1

That is a lot of knock down power.

My 5"USP is 12+1 too,but barely moves.Accurate and fast followup shots are what count,if you can't pull off 3 shots a second 7yds out you're too slow.Handguns are your worst choice of firearm but they're better than a knife or club,you have to drill them until they break down because one shot stops are rare on real criminals.

Originally Posted by rex

My 5"USP is 12+1 too,but barely moves.Accurate and fast followup shots are what count,if you can't pull off 3 shots a second 7yds out you're too slow.Handguns are your worst choice of firearm but they're better than a knife or club,you have to drill them until they break down because one shot stops are rare on real criminals.

Where did you get this info though?

Originally Posted by SouthernBoy

A handgun bullet ain't gonna knock anyone down.

Well yea, it won't take him off his feet, but it's definitely enough to stop all but the most crazed jerk on drugs.

Local news covered a story the other day, where a single round of 22 rat-shot to the belly proved to be sufficient to persuade the jerk that robbing that man's house was not a good idea. Home invasion wielding a machete, and a single round convinced him it was a bad idea.

Originally Posted by XD40inAVL

Well yea, it won't take him off his feet, but it's definitely enough to stop all but the most crazed jerk on drugs.

Local news covered a story the other day, where a single round of 22 rat-shot to the belly proved to be sufficient to persuade the jerk that robbing that man's house was not a good idea. Home invasion wielding a machete, and a single round convinced him it was a bad idea.

The thing is, unless you hit the central nervous system or the spinal cord, you really never know how your assailant is going to react to being hit. There are just too many variables to make a cut and dried statement about stopping someone or causing them to collapse. This is why proper training will include the concept of firing until the threat is eliminated (this means ceases). Now if there are multiple attackers, this concept is the best argument for "high capacity magazines". Misses, non-stopping hits, BG's who can take a lot of punishment.... all scream for having enough ammunition in your firearm to give you a chance to survive.

But the fact remains that you are not going to know whether or not your chosen caliber and load is going to do the job in an instant case until you have to call upon it to save your skin.

Originally Posted by TheLAGuy

Where did you get this info though?

It's my amd others observations from being around guns and watching crime for a few decades.

3 shots a second at close range is not hard with practice,and slow compared to the IPSC and IDPA boys.

It's long been known hanguns are not your first choice for defense,but it's kind of hard to conceal a rifle or shotgun.

One shot stops are not the norm with real criminals,that's been known for a long time.I'm talking real criminals,not the street punks like XD40 mentions stopping at the sight or a shot from a gun.Years of reading Marshall,Sanow,Ayoob and the like have backed this up.A one shot stop means you hit that small target that shuts down the CNS,not the bad guy peeing his pants because you put a 44mag throough his shoulder.Cops and Military carry large capacity mags and spares for a reason,it's likely to have multiple assailants and the real bad guys rarely stop with a shot,you have to hammer them until they stop.There are many cases where the perp was drilled with many rounds and decided to stop and didn't die,just recently I read one where a heavy guy was hit over 10 times and still walked to the ambulance but I don't remember if he lived or not.It's also been proven you can destroy a person's heart and if they're determined still have around 30 seconds to kill you before they expire.

While the majority of people don't meet up with the real bad guys,don't be complacent thinking you never will.There's a difference between a street punk and a real criminal,if you remain aware you can usually be prepared for a street punk whereas the pros have a better handle on stealth and surprise.

Originally Posted by Popeye7751

Me too!!!
They both have their place I just didn't care for the .40.. But the argument will go on forever.

Yes, the argument will be endless. As any fan of Douglas Adams will tell you the only perfect caliber would be .42!