A while back, I was drawn into a thread on anyother UBB about the 'knockdown' power of bullets, and how physics states the Hollywood style bullet deaths are *very* far fetched.  Not that I think anyone here would be under such delusions, but what got me thinking about this again was a discussion I had with a man the other day.  He was a good guy.  Member of the NRA, owned a few rifles and handguns, but obviously didn't know much about ballistics.  We were having the age old 'My *insert large caliber pistol here* would knock you on your butt' conversation; however, this guy truely belived that his .45 would put a mobile intruder on his back if hit.  My real question is, how many of you guys have run into people like this?  And what does one do?  Just agree with him or her or get into the nitty gritty of it conserning momentum and velocity of bullets?  

-Matt

Run at him with a wrecking bar raised over
your head and see if he is right.

Are you suggesting that a .45 would not knock an Intruder tits up? mmk

Never agree with them.  This shows weakness.
You must belittle them as much as possible while making your point.

hmm....don't know.  I'd rather be hit by a nine mike mike twice than a forty five once, though.  

The FBI has stats on all of this and I wish I could still remember them all, or at least post a link.  A .45 is about 94% effective when it hits the chest or head area.  (I think FBI used Federal 230grain Hydro-schock in that statistic).

Well, I'm not talking just about effective killing power as unless there is a central nervous hit, almost anyone can keep fight for at least 5 seconds.  My personal choice would be a .45 in hollow point that could  penatrate 14 inches of clothed balistic gel when fully expanded (there was a great article  about this on www.firearmstactical.com, but the web site appears to be down), but once again I'm only taking about the belived 'knockdown power' of a bullet.  The people that believe that the a person hit by a bullet will 'fly' backwards really bother me.  I don't mind that they are unaware, but when they insist that it will happen, I become a bit perturbed. I mean hell, I worked the math out, and even a .50 BMG round wouldn't put a grown man that is walking down.  Put a big hole in him that will probably cause him to topple over, but not blow him away.  Well, I guess you can't edgamucate everyone.

-Matt

EDIT:  Damn grammar. . .

In common shoulder fired rifles, shotguns, and handguns, there is no such thing as "knock down power". Rich Davis of Second Chance, the inventor of modern soft body armor, has a video of himself being shot at point blank range with a FN/FAL while standing on one foot. (he is wearing a second chance vest BTW) It does not even budge him.
Simple physics, for every action, there is an equal and opposite reaction. So if it has enough "power" to knock a 200lb man down, just think what it would do to your 180lb ass?
Of course psychological, central nerve system, all come into play. But you have to get up around a 20mm Orleikon to have a round that has real knock down power.

Dude, if you get hit by a .45 in the chest or head, you may not fly backwards, but I assure you that you will fall down as fast as Newton permits.

Now I have everyone thinking that a .45 wont kill someone.  Yes tool, you are very correct.  I hit to the central nervous system would drop someone like no ones business; however, anything else and they could have enough fight left in them to get off a shot or two.  Either way, that is why it is important not to miss.

-Matt

There's a bunch of videos out there that you can buy to see the effects of different calibers. Point being that the tests they do are only tests. Gelatin blocks dont move or shoot back/stab/swing a bat, etc.They are only good for showing depth of penetration. Thats about it.
The problem is that not every criminal is the same size weight, height,girth. That all figures in on knockdown power.A 180 lb  thug shot in the chest with a 9mm might fall down pretty quickly(barring drug use) But a 300 lb. monster THUG could take a few hits before dropping. A .22 can destroy a man just as easily as 454 Casull. Its placement that counts guys.Never forget that.At 7 yards you should be able to put all your shots in a 3x5 index card.If you cant, keep practicing till you can.
Central nervous system hits are quite effective, no matter the caliber. Hollywood has done a great job at fooling the general public into thinking there is magical properties to the rounds we shoot.But we all know better dont we?
The discussion about what caliber is best, etc is old. It has almost no bearing. You carry a .357? Great! Can you shoot it exceptionally well? Thats the question. I love my 1911, but I shoot my Sig  228(9mm) much better. I can control the recoil better and my followup shots are quicker and more accurate.
So which gun is better ? Neither. Which is better for me? The 9. Its pretty cut and dry guys. Just dont get caught up in the rat race of it all. Shoot the one you own that you shoot best with.Shoot accurately consistently and the magical one stop shot is yours,when you need it most, with whatever caliber it is you choose. The bad guy doing the backflip after being shot trying to mug you, well, thats a Hollywood story just for us fellow listers here.[:D]
Be safe, shoot straight, and remember, its not how many shots or the size of the bullet, its where you place em that counts!To quote Front Sight"Any gun will do, if you will do!"
Synweap223 Out!

There was a link on here that had some footage of people shooting something called a T-REX. (a nickname they gave this elephant gun, I can't recall the cartrige it shot)  It did knock people flat on their ass when they shot it, does this mean it would knok a man flat on his ass when he was hit?  I have never seen someone drop a rifle so many times, actually the recoil blew it out of thier hands!  I will have to look for the link.  

thats why i defend my home with 577 tyranasaur

I'm looking for the sight in my history.  Make sure you have the volume on if you find it before I post it.  You will laugh till your stomach hurts.

TIMETOFEEDTHEHOGS check out the TREX VIDEO POST

577 Tyrannosaur

[url]http://www.accuratereloading.com/videos.html[/url]

The FBI doesn't have such stats. Rather, it is Marshall and Sanow who publish that. And it isn't based upon sound science, and I don't recommend it. However, you can find some of their data here:

http://www.evanmarshall.com/towert/

In the early '90s I was with a team installing a scientific installation in the California desert. A local contractor (I believe he had a concrete pumping buisness) and I spent some time talking firearms. He was convinced a .45 would knock someone down, and he even stated that it was a good weapon for his wife, 'cause most likely its muzzle blast alone would do the job. I don't know if he was serious, but I didn't try to set him strait.

Some time later, I was with an ex-college buddy who hailed from Berkley and who was a gun-banning lefty. He was of the opinion that a .22 should suffice for self defense, and that a .45 was only needed for stopping charging Zulus in their tracks. I had been arguing with him, but I have to say that comment left me speechless. It just seemed so ignorant on so many levels that I didn't know where to begin to respond. Edit: I almost forgot, both me and my college buddy were physics majors at UCSD.

Bet a intruder would fly backwards with a 12 gauge slug or two.

Sorry Tool, but the .45 is not a magic bullet. Just 'cause you hit 'em center of mass does not mean they will fall down. Documented cases are all too common. Deputy sheriff shot 8 times in the chest,upper abdominal area, no vest. He shot the 2 armed robbers to death with his .38spl revolver.
The .45 is a good PISTOL round. The myth, and it is an urban myth, of how great the "knock down power" of .45 is pure unadulterated BS. Shotgun slugs, even rifles, do not have knockdown power. Simple physics. I have seen people killed by .22's, others with simular shots only wounded by magnums and .45's. It often makes no sense. I do gurantee you one thing, a 30.06 contact wound to the head will blow the head off, I know, 'cause I wore a guys head one time. (at least large portions of it)