9mm VS .45

[jmjames]

What if the charging 1000 pound bear mauls you before your 5th shot?

I'm not a east coast city person. I carry a gun for more reasons than self defense from people......

If your concern is a charging 1,000 bear mauling you and needing to stop it within 5 rounds, there are loads far superior for that purpose to either 9mm or .45, so its a moot point. Likewise, the firearms that are suitable for self defense in a city situation are quite possibly not the best options for an outdoors scenario.

I am scheduled to go hog hunting for the first time this weekend. I'm bringing an P30 loaded with 9mm with me, and based on reports from people who I personally know that have hunted boar with 9mm, I feel perfectly comfortable with that selection. I keep wondering if I should also bring my 1911 as well, but it never crossed my mind to bring my 1911 with me instead.

I agree with a previous poster, this thread does feel like stirring a pot for no good reason.

J.Ja

[LOKNLOD]

Rodney, don't take this the wrong way, because I know you're just making observations based on your personal experience, but I believe you are misinterpreting that data a bit.

The addition of armor to the mix is drastically changing the dynamics of the situation you are trying to assess, to the point that you are no longer able to make fully valid inferences about the phenomena you are trying to study.

This is similar to saying that the .45 is more reliable at knocking down steel plates than the 9mm, therefore it has more "knockdown" or "stopping" power. But the physics at work when a bullet hits a rigid mass like a steel plate or armor are very different than when a bullet penetrates flesh.

In inelastic collisions like bullets are experiencing, momentum is conserved, kinetic energy is not. Momentum is velocity*mass, so the .45 has a big advantage here over 9mm. Shooting a plate will result in transferring momentum to the plate, thereby giving it some velocity, but not much, because of the increased mass. (Getting ahead of ourselves a bit, as the targets mass becomes sufficiently large, the imparted velocity is negligible, which is a part of the reason a person doesn't get knocked down by bullet impact alone.) Nonetheless, this is why if you're shooting some steel at a match that guy with the 230gr ball looks like he's slapping them with the hand of God compared to your light 115gr FMJ practice loads which make you curse whoever calibrated the steel that day.

So when you shoot bullets into armor, it is bringing them to an abrupt stop much like the steel plates. By not allowing the bullet to penetrate, its assuring that the full momentum of the bullet impact is transferred VERY rapidly. And the impulse, the force, of the impact is the change in momentum over the length of time it occurs. The sudden stop is maximizing the force of the impact by making that time (the denominator) smaller. But when comparing pistol rounds, the momentum on top of the equations becomes dominant. The 9mm may be moving a little faster making that time less by a small percentage, but that .45 has nearly twice the momentum (due to the mass) so it's applying a much larger force to the rigid body of the target. Result, steel goes down, flesh gets bruised, perhaps ribs get broken. Exaggerated and oversimplified example: Shooting a bullet into steel or armor is like holding your hand out rigidly to catch an egg thrown at you. SPLAT. Catching the egg by moving your hand away will cushion the blow. Right? Well, that's sort of how the bullet entering flesh and coming to rest over a longer period of time behaves. I did say exaggerated and oversimplified, right?

The .45 will always have more momentum to transfer, so it must be universally better, right? Well, it depends. Momentum and force aren't what cause death (unless you shoot someone a lot with HUGE, slow bullets and the coroner calls it blunt force trauma) and certainly aren't what cause immediate incapacitation. The bullets have to hit/destroy something important (preferably something related to the central nervous system) and/or provide a path for enough blood to leave the body for important parts to stop working.

That's not to say that there are not physics based advantages to bigger bullets. More momentum certainly brings the advantage of being able to break through intermediate barriers (internal or external to the body of the target) while maintaining enough of that momentum to still damage the aforementioned critical bits. To a lesser extent, a bigger diameter is still a bigger hole and slightly larger swath that might contact those important parts. The complex dynamics of what pistol bullets do in flesh is a whole science in and of itself that people and agencies have spent huge sums of time and money studying. To try and infer what happens in flesh based on the results of shooting steel or armor just doesn't do the topic justice, and can be misleading.

The point is not that there is no difference between .45 and 9mm. It's that the differences are complex, subtle, and, unless the bullets find the right innards to wreck, they might be moot.

And when things start approaching rifle velocities everything goes completely crazy.

[jetfire]

I suppose it was only a matter of time before we had one of these.

I carry a .45, but I don't believe it has any more magical power than a 9mm. And since there's no empirical evidence that proves otherwise, I won't lose any sleep if I have to switch back to 9mm. I'd much rather worry about becoming a better shooter than whether my roundof choice is better for "rapid-fire-double-tap-stopping-power".

[tremiles]

Editing my post because I feel dirty for participating in a caliber war thread.

Sent from my DROID2 using Tapatalk

[agent-smith]

I'm a little slow here - Could you please video yourself performing both of the above tests (on yourself of course), and then post the results here?

[BWT]

I'm switching from .45 ACP to 9mm.... One of the many reasons is I wouldn't have to reload the gun to finish that test.

[DocGKR]

Please......this is the most insipid thread I've had the misfortune to read at PF...

[Ed L]

I can't believe that what follows is a serious post.

I have a test for anyone who says that there is only a small difference between 9mm and .45 ACP.

1. Aquire a soft armor vest. (i.e. bullet proof vest)

2. Have 9mm and .45 caliber pistol

3. Acquire 10 rounds of self defence ammunition in both calibers, same brand for both.

4. Put on soft armor vest.

5. Load 9mm pistol with 10 rounds.

6. Shoot yourself in the chest (with body armor on) 10 times.

7. Take notes on how it felt and take pictures of your bare chest every day for the next 20 days. Do 20 pushups on 7th day. Note how it feels.

8. On the 21st day put on your soft armor vest again.

9. Load .45 with 10 rounds.

10. Shoot yourself in the chest (with body armor on) 10 times.

11. Take notes on how it felt and take pictures of your bare chest every day for the next 20 days. Do 20 pushups on 7th day. Note how it feels.

12. Now tell me there is only a small difference between 9mm and .45. Your chest will disagree with you.

This not a joke. It is reality. As a lifelong hunter, I know that differences in calibers do matter. It's the difference between a one shot kill and a one shot hit

that results in chasing a wounded animal for miles. Get real people.

[Jay Cunningham]

The point of this post is to troll.

Please don't do it. Go read DocGKR's research on wound ballistics and terminal effects of handgun ammunition.

This thread has run its course - quickly.