Conversation with a lady friend.

[Voodoochile]

Some how a conversation about firearms came up with a lady friend today, the part that really was the core of the conversation was caliber or chambering of semi autos mainly 9mm, .40S&W & .45ACP.

The question was, what's the real difference or advantages of a .40 over a 9mm because she normally carries a .40S&W Glock but the guards carry 9mm Glocks.
Now I am by no means an expert on this subject, only either by reading many articles, talking to those who use these weapons or by my own experience but am still no authority in this but my explanation to her was this..

For the most part, the standard pressure rounds between all 3 chamberings will have similar striking energy within 80 FT. LBS. of each other but the difference is the speed in which the rounds impact & the diameter of the projectile.
The .45ACP round has almost 1/2" diameter to work with at the beginning where the 9mm only has 3/8" diameter.
Now granted all 3 rounds are very effective defensive pistol chamberings, top that with modern hollow point projectiles & they have the potential to become a little more effective in those defensive scenarios.
Here is where things get a little different.
Say a LEO is in a situation where they need to shoot through a windshield or a car door to stop the BG from continuing the fight, that is where those hollow points may not function as designed & the projectile react like a FMJ when they strike the intended target.
The slightly larger projectile would be advantageous because it may have the permanent wound that could cause the fight to end that much quicker than if the smaller although as effective round was used.

.45ACP 230gr. Average Ballistics = 800 - 950 FPS & 325 - 400 FT. Lbs.
.40S&W 165gr. Average Ballistics = 1000 - 1150 FPS & 400 - 480 FT. Lbs.
9mm 124gr. Average Ballistics = 1100 - 1200 FPS & 320 - 400 Ft. Lbs

The other part that I told her was ammunition availability, in the same size pistols there would be around 15+ rounds in the 9mm, 10+ rounds in the .40S&W & 7+ rounds in the .45ACP.

Told her that by what I have read & by me talking to a few LEO's who carry the .40, the .40S&W is a good compromise in ammo count & power when those types of situations possibly could come up.

What do y'all think about my uneducated explanation of this subject?
By the way she is a LEO in the Metropolitan Northern Virginia area.

 

[kokapelli]

Another big factor would be that the 9mm might be much easier for her to control which could translate into more effective shots with the 9mm.

 

[tlynch]

Another big factor would be that the 9mm might be much easier for her to control which could translate into more effective shots with the 9mm.

Beware of caliber preconceptions. My wife far prefers .45 ACP to 9mm in similar size guns. As near as I can tell, the issue for her is that bigger but slower recoil impulse is preferable to sharper but lighter. I was surprised, but I bet she isn't the only one to feel that way.

Tom

 

[Unemployedshooter]

At my LE academy, the range instructors shot a foam torso with soft body armor with 9mm and .40. The difference in energy transfer going from 9mm to .40 was noticeable. 9mm made the torso wiggle a little. The .40 made it jump and slide back.

Don't get me wrong, I like 9mm. If you can accurately shoot .40, go for it.

 

[Voodoochile]

I did say that the standard loadings had similar striking energy between the 3 different chamberings within about 80 Ft. Lbs., not +P or +P+.

You are right though, I do not know much about fluid dynamics but my example does apply to each of those rounds where if the we're to hit a barier like a wall or part of a car even the best hollow points would struggle to perform as designed once past that obsticle & does hit soft tissue.

My wife likes her .45ACP & shoots it very well but does also like her new 9mm as well.

 

[MedWheeler]

This sounds more like a thread on terminal performance and ballistics of those three calibers than one on a "conversation with a lady friend"...

 

[Skribs]

It's really simple.

Bigger rounds make bigger holes. They also have bigger recoil and cost, and less rounds per magazine. There is no accurate way to quantify what is better.

In general, I prefer a 9, especially in a carry piece which is probably smaller. However, carrying a 40 or 45 will still give you a lot of firepower.

If everyone else in the area is using 9, then 40 or 45 is more likely to be available during a shortage or scare.

I'd go for all 3 and carry the one with the most ammo per mag that you have ammo for, if it were me.

 

[Normandy]

A fairly thorough study of 9mm vs .40S&W was recently published in Shotgun News (iirc), or maybe it was on one of the gun shows. I subscribe to SGN, Handguns, and G&A, and I watch the Outdoor Channel a lot.

Anyhow, the conclusion was that 9mm and .40S&W create virtually the same wound channel, have roughly the same penetration, and no real significant difference was noted. They did say that the recoil (and ANTICIPATED recoil) of the .40 cal could affect accuracy, so the recommendation was that 9mm, with its more controllable recoil, was superior due to quicker recovery from recoil, and tended to be shot more accurately.

As for "bigger has more recoil", that's just not the case. The Makarov round is generally shot from a blow-back pistol, and hurts my hand as much as the .40 does. And it's basically a .380+P. I manage 9mm and .45ACP recoil just fine, but not the Mak or .40.
YMMV.

 

[leadcounsel]

I swear I'm going to design a gun that shoots 3 bullets with the single pull of a trigger: A 9x19, .40 cal, and .45 cal. This will put and end to this debate...

 

[JWH321]

I swear I'm going to design a gun that shoots 3 bullets with the single pull of a trigger: A 9x19, .40 cal, and .45 cal. This will put and end to this debate...

9mm is best. Why? Because I have a whole bunch of it. If I switched, I'd have to buy more ammo. Therefore, 9mm is best.

Makes sense to me.

 

[Delford]

Same here, only it's.45 ACP