Knock down power of a 40?

[getusumtx]

Hi, I am writting a paper for my college english class and want to talk about the balstics of a .40 S&W 180 grain bullet. DOes anyone know the formula to calculate the amount of force behind the bullet?Thanks for your help..

[melkor41]

Is it not just mass X velocity?

[agbullet2k1]

Technically that's momentum (still important though). mass*acceleration would be force, so you need to find out how long it takes for said bullet to go from impact to stop in the target. Once you have the time, just take the momentum and divide by the time. Just make sure to keep your units straight. Were you looking for just simple algebraic methods or do you want the more complex calculus stuff?

EDIT: While you're at it, why not consider touting energy deposit? 0.5*mass*velocity^2. Whole lot easier to work with than figuring out how much time the bullet needs to stop.

[CHL/LEO]

Does anyone know the formula to calculate the amount of force behind the bullet?

For info on this go here
or
here
or
here

Discovery Channel even has something on it: Click here

[Dan20703]

Does anyone know the formula to calculate the amount of force behind the bullet?

For info on this go here
or
here
or
here

Discovery Channel even has something on it: Click here

.....or here too!
http://www.firearmexpertwitness.com/cus ... lcnrg.html

[yerasimos]

I would kindly suggest reconsidering the subject matter for your college English class assignment, in favor of a more mundane topic. In the aftermath of tragedies such as Virginia Tech, I have read that many college campuses are taking a dim view of any interest in violence, and that some professors, RAs/RDs, administration personnel, etc, have been "deputized" to be on the lookout for "suspect" behavior. Disclosing an interest in firearms, ammunition, ballistics, etc, could be interpreted to your disadvantage.

I know that the First Amendment is supposed to be protected by the Second Amendment, and I know there are many people here who seek to "mainstream" the "gun culture". However, we must recognize the fact that our rights are routinely infringed these days in normal activities such as seeking an education or boarding an aircraft. In the interest of minimizing trampling upon the residual privileges, we frequently have to second-guess and adjust our own behavior. Such is life in the Homeland.

Take or leave my advice, as I believe you should be free to make your own choice.

[Liberty]

I would kindly suggest reconsidering the subject matter for your college English class assignment, in favor of a more mundane topic. In the aftermath of tragedies such as Virginia Tech, I have read that many college campuses are taking a dim view of any interest in violence, and that some professors, RAs/RDs, administration personnel, etc, have been "deputized" to be on the lookout for "suspect" behavior. Disclosing an interest in firearms, ammunition, ballistics, etc, could be interpreted to your disadvantage.

I know that the First Amendment is supposed to be protected by the Second Amendment, and I know there are many people here who seek to "mainstream" the "gun culture". However, we must recognize the fact that our rights are routinely infringed these days in normal activities such as seeking an education or boarding an aircraft. In the interest of minimizing trampling upon the residual privileges, we frequently have to second-guess and adjust our own behavior. Such is life in the Homeland.

Take or leave my advice, as I believe you should be free to make your own choice.

Once they have silenced us, they have won and we have lost.

[The Annoyed Man]

Here is an answer in practical terms...

My father shot a Japanese soldier in the stomach on Iwo Jima from about 10' away with his .45. I asked him what happened. Dad said, "He sat down abruptly." Further questioning revealed that the enemy soldier's legs buckled and he collapsed. He did not get "Knocked Down." It would be accurate to say that the bullet put him down, but it would be an exaggeration to say that he was "knocked down" in the Hollywood sense.

Now, I don't know for sure the ballistics of GI .45 hardball coming out of a 1991-A1 during WW2, but I believe the bullet was a 230 gr round nose FMJ, traveling at somewhere around 835 fps, delivering about 352 ft lbs of energy at the muzzle. Looking at modern ammunition, Federal Cartridge Company's website lists the following for the .40 S&W 180 gr Hydro-Shok versus the .45 ACP 230 gr Hydro-Shok:

.40: 1000 fps at Muzzle, 400 ft lbs at Muzzle (4" test barrel)
.45: 900 fps at Muzzle, 414 ft lbs at Muzzle (5" test barrel)

In other words, they are pretty close in performance at point blank distance with the .45 having a slight edge. As distances increase, the .45's performance edge grows a little larger.

If an older .45 bullet made an enemy soldier sit down abruptly, it's not likely that a modern .45 bullet with just 17% more energy is going to flat knock a man down; and if a .45 won't do it, a .40 won't either. Be that as it may, 3 or 4 rounds of either is pretty much going to wreck his day.

Now rifle bullets are an entirely different matter. Hours before my dad shot that unfortunate Japanese, my dad was shot himself by a Japanese rifle bullet which struck him in the solar plexus and exited his back just to the left of his spine. I asked him what it was like, and he said that this bullet did flat knock him down and backwards, and that it felt like getting kicked by a draft horse right in the ribs. He said it seemed to take forever to get his wind back, and when he finally "re-entered reality," he was down, on his back, not where he had been crouching when hit. I don't ever want to get shot by anything, but if it ever does happen to me, please Lord, let it be a pistol bullet, and not a rifle or a shotgun.

Just my 2¢, although I agree with others that, in a college English class, bullet knockdown power is probably a more provocative essay subject than wisdom would dictate. BTW, after the war, my dad became a university English professor.

[yerasimos]

Once they have silenced us, they have won and we have lost.

I reckon that you and I both understand that people like us who respect the lives, liberty and property of others are greatly outnumbered by the collectivists of various stripes who do not. Unfortunately, quantity has a quality of its own, and we have to account for this.

Just because someone can or should be free to say or do something in a given context does not mean that one should go ahead and say/do it in that context. There are more opportune times to speak about the subject of firearms than a college English essay, and given universities' frequent institutional hoplophobia, I stand by what I wrote earlier, seeking the best interest of the original poster.

Interesting anecdotes, TAM. FWIW, I believe that each gunshot wound is more or less unique, and that a live target's reaction to the wound will largely depend upon the depth of the wound and whether the wound permanently damages various systems (circulatory, nervous, pulmonary, etc). Assuming a bullet strikes a target after moving horizontally, I do not see how this would directly trigger vertical collapse or "knock down". There so many variables involved in terminal ballistics, beyond simple calculation, that one should not be surprised by anything.

[seamusTX]

I have to agree with Yerasimos on this one. It's one thing for an adult to write a "politically incorrect" article for publication. Students are in a different situation. They do not have the same freedom of speech and the press that adults in general have. Last year, the U.S. Supreme Court upheld the power of a school to discipline a student who displayed a protest sign (admittedly weird) off school property.

I would not be surprised if a student writing an essay on terminal ballistics was suspended and referred for psychological evaluation.

Here's an idea for Getsumtx that will tie the teachers in knots: Write an essay on the racist roots of "gun control." Long before there were any general limitations on the RKBA, slaves, free blacks, and Indians were restricted in their ownership and use of firearms. Even when laws were sometimes written in non-discriminatory language, they were enforced only against minorities.

Here's one example that makes many people uncomfortable: In the 1960s, it was legal to carry a firearm openly in California, and the Black Panthers took to carrying rifles. Newspapers editorialized about "Negroes with guns." The "problem" was "solved" when the Mulford Act, which banned carrying weapons in a vehicle or a public place, was signed into law by Govenor Ronald Reagan in 1967.

There is plenty of information about this on the Internet.

- Jim

[Liberty]

Its been a long time since I've been to college, I suppose things have changed. Ballistics was studied in high school physics class and was a part of High School and college algebra.
We discussed Everything from the trajectory of a rockets to the shotgun slug to rocks. Times have changed I guess and maybe we have already lost and I didn't know it. but, shucks, wasn't the Fermi project a university project? Don't most colleges in Texas have ROTC? As I recall A&M has a nuclear reactor. It seems wierd that ballistics would be off topic in an college English class.

[zx9rt1]

When someone ever finds out about "knock down power" I would like to know how they manage that from point A to point B with out "knocking" themselves down. Myself, I would rather STOP someone than to "knock them down". I'll be waiting on that report of knock down power.

Michael

[WildBill]

Hi, I am writting a paper for my college english class and want to talk about the balstics of a .40 S&W 180 grain bullet. DOes anyone know the formula to calculate the amount of force behind the bullet?Thanks for your help..

I tend to agree with Yerasimos and SeamusTx. Even without the political ramifications, I think this is a poor topic for an English class essay. One of the first rules of written communication is to know your audience. Just because the subject is interesting to you and people on the TexasCHLforum, I don't think the vast majority of readers, including your English professor, would find 40S&W ballistics an interesting subject. It's not a matter of being "off-topic" or "taboo" but whether it is appropriate for the particular class. The bottom line is, if people don't have any interest in the subject matter, they will not want to read your essay. I am making a big assumption, but if the English professor wanted to read essays about ballistics, he or she would have become an Engineering or Physics professor.

Your paper isn't going to be published or make any major political statement - it's simply about doing what it takes to get a good grade in your class. I am still wondering how you plan to treat this topic without sounding like a typical article from a gun magazine.

If we haven't discouraged you from writing on "knock down power" please post your finished essay so we can read it.

[MoJo]

If you want REAL knockdown power use a Louisville Slugger or a pickup truck!

[seamusTX]

Its been a long time since I've been to college, I suppose things have changed. Ballistics was studied in high school physics class and was a part of High School and college algebra.

It was in my day, too; but we didn't talk about wound channels in English class.

- Jim