[clee]

yes, the perpetual debate goes on, and maybe i was truly bored, but two recurring themes we continually see:

The .40's recoil is much harsher than the 9mm:

below is a table i found from winchester, i entered the XD weight (lbs) and it calculates recoil in ft-lbs for some of their standard ammo


Firearm, Ammunition, Bullet Wt, Powder Wt, Velocity, Recoil

XD9, 9mm 115 gr, 115, 6, 1190, 4.21
XD9, 9mm 147 gr T Series, 147, 4.8, 990, 4.59
XD9, 9mm 124 gr. +P, 124, 5.8, 1180, 4.76
XD9, 9mm 127 gr. +P+, 127, 6.2, 1250, 5.63

XD40, 40 S & W 180 gr., 180, 6.2, 990, 6.39
XD40, 40 S&W 180 gr. T Ser, 180, 6.4, 990, 6.40
XD40, 40 S&W 165 gr. T Ser, 165, 6.9, 1140, 7.22

Thoughts? appears that in generic ammo you're picking up roughly 50% more recoil with the .40. Interesting that the 9mm in +P+ doesn't kick as much as the .40

The .40 makes a bigger hole

Obviously this is true, but how much bigger?

.40 inches = 10.16 mm

Bulltet cross-sections (w/o expansion, need some more data...):

Pi * (10.16/2)^2 = 81.07 square mm's

Pi * (9/2)^2 = 63.61 square mm's

81.07 / 63.61 = 1.27449

Conclusion: the hole made (entering) by a .40 is 27.5% bigger than that made by a 9mm. Not as big a difference as you may have thought...



Ok guys, i know this debate is beaten to death..... but might as well get some numbers rather than hype involved....

merry christmas to all!

 

[dolanp]

Well all the numbers in the world won't save your ass if you can't hit your target. :wink:

IMO, the 9 is easier to make quick follow-ups on target because of the lower recoil. They each have their merits.

 

[TCD]

.40 inches = 10.16 mm

Conclusion: the hole made (entering) by a .40 is 27.5% bigger than that made by a 9mm. Not as big a difference as you may have thought...

and 9mm is about .380 or so right? If you know that a .40 is a 10mm the difference is only 1 mm... I thought this was common knowledge.

.40s are generally more massive, and a larger bullet itself, the expansion results may be different.

Additionally, I see a 2 ounce weight difference in a 9mm versus a .40 frame. Are these factored in? What about loaded versus unloaded magazines? 10 round versus 12/15?

 

[IMPALAon20s]

size of hole ammo would leave, isn't quit what matters. way it was explained to me by gun store dude, the 9 travels at much higher velocity, so you would have to concern yourself with how much damage BEHIND the TARGET (intruder/asalent) you do. where the .40 would probably stay lodged in them. i orginally wanted a .40 for this reason, but since unavailable, i got the 9. my thinkin was, i could hold more ammo , 15+1, and if using expanding ammo (hollow point), i dont have as much likelyhood for bullet to travel THRU my target and endanger bystanders. btw, i hope that my theory/thinking never has to be proven wrong or right.

 

[gbob01]

I carried a 9 for many years and now carry a .40 for work and CCW.
I don't have a problem with either round. As I've always believed, its shot placement, not hole size that will determine the winner.

 

[bcphoenix]

There's a property of a bullet called sectional density which is the weight divided by the cross sectional area. What it is is a gauge of how well the bullet should penetrate. There's a good write up on www.firearmstactical.com on the subject.

I did a spreadsheet on it once where I calculated the sectional density of all calibers available in XD pistols. 9mm with the 147 gr weight had the best followed by 357 sig in a 147 gr weight (Hornady makes one) followed by 40 in the 180 gr weight. They were all so close they were right on top of eachother. The lighter bullets in each caliber were much lower in terms of sectional density even though they offer greater muzzle energy. I tend to favor the heaviest bullet I can get for a given caliber.

I actually own both 9mm and 40 as defensive handguns and am happy with both. As one of the previous posters said, shot placement is more important than bullet selection as long as you stick to the 4 major auto pistol calibers (9mm, 357 Sig, 40 and 45 ACP).

Another thing to consider is barrel length. I wouldn't want the aggravation of a short barreled pistol in 40 due to the ouch-factor. But the 5" XD tactical model makes the snappy 40 round into a pussycat. The extra barrel length also pumps the energy up to around 600 ft-lbs but that's a subject for another post :twisted:

 

[DanaT]

There's a property of a bullet called sectional density which is the weight divided by the cross sectional area. What it is is a gauge of how well the bullet should penetrate. There's a good write up on www.firearmstactical.com on the subject.

I did a spreadsheet on it once where I calculated the sectional density of all calibers available in XD pistols. 9mm with the 147 gr weight had the best followed by 357 sig in a 147 gr weight (Hornady makes one) followed by 40 in the 180 gr weight. \

Maybe my math is a little off, but why would a 357Sig 147gr and a 9mm 147gr have a secional density? They both use the same diameter of bullet and both weigh the same. Now if A=B and C=D then A/C = B/D.

Also, ability to penetrate is not just sectional density. I promise you a 9mm bullet travelling at 1200ft/sec will penetrate less than the same bullet travelling 1400ft/sec.

-Dana

 

[Forsaken]

I have been around this debate for twice as long as we had the ,40 S&W. From a reloading standpoint the 9 X 19 Para. is probably as good a defensive round as you will ever need from a pistol. Like another reply stated, if you know animal attacks may be eminent, carry a rifle or shotgun.
American made 9mm ammo is underpowered, and not the cartridge itself, the most overlooked aspect of the 9mm by gunshop commando's. The cartridges pressure rating was reduced to 35,000 PSI around the time of the forties introduction. It's former rating was 35,700 CUP (copper units of pressure) which translated to the current PSI system is 38,500 or the max. rating for +P in 9mm. Bullet design is critical, only good JHP's should be used for defense.
Most shooters may not be aware, but it is felt by reliable, experienced pistoleros that 500 ft. lbs is the optimum level necessary for a defensive cartridge. This is not big news, and one of the reasons the 125 gr. JHP in .357 mag. has such a reputation for effectiveness and it is warranted. If your defensive ammo can generate close to 450 ft. lbs. and has a JHP bullet that expands and penetrates reliably, forgetaboutit. The .45 acp works, the .40 S&W works, the .357 SIG works and at this power level the 9mm shines. The equation for kinetic energy is Velocity Squared X bullet weight in grains / 450436. I would avoid 147 gr. subsonic, but Cor-Bon does make a +P load that should exceed 1100 FPS in the longer (4.72) barrel of the CZ 75 SA. The best all around weight in 9mm is probably 124 gr. and Black Hills and SPEER both make +P loadings that are rated 1250 FPS or higher depending on barrel length. Handloading makes the 9mm excel and if you really know what you are doing a 115 gr. JHP can be safely loaded close to 1400 FPS, the 124 gr; 1300 FPS, the 147 gr; at or above 1150 FPS which will give similar ballistics to the .357 SIG or the .40 S&W.
There has always been a bias against the 9mm because it shoots a lighter, faster bullet that will generate more kinetic energy than standard .45 acp JHP's. Sometimes, the kinetic energy equation is questioned because caliberites believe it unfairly tilts in the 9mm's favor. In IPSC they developed a formula that they felt corrected this by accentuating bullet weight to momentum: Bullet wt. X Velocity / 1000 gives a calibers Power Factor and while IT IS math, the kinetic equation is physics, based on Einsteins theory. Remember E=MC2. Well, it works with bullets.
I said at this power level the 9mm shines. The reason; because of lower recoil at the same or higher kinetic energies. People who have long made their livings in lethal combat will tell you, no matter what caliber handgun you shoot, The double tap is paramount and sometimes the triple tap is most recommended. Ever hear this? Two in the chest, one in the head?
Arguably, the most lethal warriors in the world, The British SAS have long held this doctrine. What caliber do they shoot in handguns? The 9 X 19 Para. As do the Navy S.E.A.L.s. You will see them them with silenced .45 acp's ( Subsonic ) for sentry elimination, but their defensive sidearm is the SIG- Sauer P-226 in both cases. Old wives tales and the FBI's poor selection of bullets doesn't mean much in their world.
BTW, I have heard of some box-stock CZ 75 SA's achieving 1/2" groups at 25 yards, It should be a shooter. Practice the double tap often and keep it loaded with a +P+ level 115 gr. JHP or a +P 124 gr. JHP. Because placement is almost everything and recovery speed between shots will make up the difference.

 

[bcphoenix]

I have been around this debate for twice as long as we had the ,40 S&W. From a reloading standpoint the 9 X 19 Para. is probably as good a defensive round as you will ever need from a pistol. Like another reply stated, if you know animal attacks may be eminent, carry a rifle or shotgun.
American made 9mm ammo is underpowered, and not the cartridge itself, the most overlooked aspect of the 9mm by gunshop commando's. The cartridges pressure rating was reduced to 35,000 PSI around the time of the forties introduction. It's former rating was 35,700 CUP (copper units of pressure) which translated to the current PSI system is 38,500 or the max. rating for +P in 9mm. Bullet design is critical, only good JHP's should be used for defense.
Most shooters may not be aware, but it is felt by reliable, experienced pistoleros that 500 ft. lbs is the optimum level necessary for a defensive cartridge. This is not big news, and one of the reasons the 125 gr. JHP in .357 mag. has such a reputation for effectiveness and it is warranted. If your defensive ammo can generate close to 450 ft. lbs. and has a JHP bullet that expands and penetrates reliably, forgetaboutit. The .45 acp works, the .40 S&W works, the .357 SIG works and at this power level the 9mm shines. The equation for kinetic energy is Velocity Squared X bullet weight in grains / 450436. I would avoid 147 gr. subsonic, but Cor-Bon does make a +P load that should exceed 1100 FPS in the longer (4.72) barrel of the CZ 75 SA. The best all around weight in 9mm is probably 124 gr. and Black Hills and SPEER both make +P loadings that are rated 1250 FPS or higher depending on barrel length. Handloading makes the 9mm excel and if you really know what you are doing a 115 gr. JHP can be safely loaded close to 1400 FPS, the 124 gr; 1300 FPS, the 147 gr; at or above 1150 FPS which will give similar ballistics to the .357 SIG or the .40 S&W.
There has always been a bias against the 9mm because it shoots a lighter, faster bullet that will generate more kinetic energy than standard .45 acp JHP's. Sometimes, the kinetic energy equation is questioned because caliberites believe it unfairly tilts in the 9mm's favor. In IPSC they developed a formula that they felt corrected this by accentuating bullet weight to momentum: Bullet wt. X Velocity / 1000 gives a calibers Power Factor and while IT IS math, the kinetic equation is physics, based on Einsteins theory. Remember E=MC2. Well, it works with bullets.
I said at this power level the 9mm shines. The reason; because of lower recoil at the same or higher kinetic energies. People who have long made their livings in lethal combat will tell you, no matter what caliber handgun you shoot, The double tap is paramount and sometimes the triple tap is most recommended. Ever hear this? Two in the chest, one in the head?
Arguably, the most lethal warriors in the world, The British SAS have long held this doctrine. What caliber do they shoot in handguns? The 9 X 19 Para. As do the Navy S.E.A.L.s. You will see them them with silenced .45 acp's ( Subsonic ) for sentry elimination, but their defensive sidearm is the SIG- Sauer P-226 in both cases. Old wives tales and the FBI's poor selection of bullets doesn't mean much in their world.
BTW, I have heard of some box-stock CZ 75 SA's achieving 1/2" groups at 25 yards, It should be a shooter. Practice the double tap often and keep it loaded with a +P+ level 115 gr. JHP or a +P 124 gr. JHP. Because placement is almost everything and recovery speed between shots will make up the difference.

I think the SEALs use 147 gr subsonic ammo in their 9mm P226's. There was a bunch of it on sale surplus at www.ammoman.com. Could've been machinegun ammo but I doubt it. I agree though that the caliber snobs have given 9mm a bad rap. Perhaps it's to justify their plunking down a grand or more on a .45 they probably won't carry because they don't want to get any scratches on it.

I also agree that the FBI could've fixed their firepower deficiencies by chosing better ammo for the 9mm's and .38's they had in service. They've been through what, 5 different handguns/calibers since the Miami gunfight? Now I think they're carrying Glock 23s in .40 (can anybody say KABOOM?).

 

[Forsaken]

I have been around this debate for twice as long as we had the ,40 S&W. From a reloading standpoint the 9 X 19 Para. is probably as good a defensive round as you will ever need from a pistol. Like another reply stated, if you know animal attacks may be eminent, carry a rifle or shotgun.
American made 9mm ammo is underpowered, and not the cartridge itself, the most overlooked aspect of the 9mm by gunshop commando's. The cartridges pressure rating was reduced to 35,000 PSI around the time of the forties introduction. It's former rating was 35,700 CUP (copper units of pressure) which translated to the current PSI system is 38,500 or the max. rating for +P in 9mm. Bullet design is critical, only good JHP's should be used for defense.
Most shooters may not be aware, but it is felt by reliable, experienced pistoleros that 500 ft. lbs is the optimum level necessary for a defensive cartridge. This is not big news, and one of the reasons the 125 gr. JHP in .357 mag. has such a reputation for effectiveness and it is warranted. If your defensive ammo can generate close to 450 ft. lbs. and has a JHP bullet that expands and penetrates reliably, forgetaboutit. The .45 acp works, the .40 S&W works, the .357 SIG works and at this power level the 9mm shines. The equation for kinetic energy is Velocity Squared X bullet weight in grains / 450436. I would avoid 147 gr. subsonic, but Cor-Bon does make a +P load that should exceed 1100 FPS in the longer (4.72) barrel of the CZ 75 SA. The best all around weight in 9mm is probably 124 gr. and Black Hills and SPEER both make +P loadings that are rated 1250 FPS or higher depending on barrel length. Handloading makes the 9mm excel and if you really know what you are doing a 115 gr. JHP can be safely loaded close to 1400 FPS, the 124 gr; 1300 FPS, the 147 gr; at or above 1150 FPS which will give similar ballistics to the .357 SIG or the .40 S&W.
There has always been a bias against the 9mm because it shoots a lighter, faster bullet that will generate more kinetic energy than standard .45 acp JHP's. Sometimes, the kinetic energy equation is questioned because caliberites believe it unfairly tilts in the 9mm's favor. In IPSC they developed a formula that they felt corrected this by accentuating bullet weight to momentum: Bullet wt. X Velocity / 1000 gives a calibers Power Factor and while IT IS math, the kinetic equation is physics, based on Einsteins theory. Remember E=MC2. Well, it works with bullets.
I said at this power level the 9mm shines. The reason; because of lower recoil at the same or higher kinetic energies. People who have long made their livings in lethal combat will tell you, no matter what caliber handgun you shoot, The double tap is paramount and sometimes the triple tap is most recommended. Ever hear this? Two in the chest, one in the head?
Arguably, the most lethal warriors in the world, The British SAS have long held this doctrine. What caliber do they shoot in handguns? The 9 X 19 Para. As do the Navy S.E.A.L.s. You will see them them with silenced .45 acp's ( Subsonic ) for sentry elimination, but their defensive sidearm is the SIG- Sauer P-226 in both cases. Old wives tales and the FBI's poor selection of bullets doesn't mean much in their world.
BTW, I have heard of some box-stock CZ 75 SA's achieving 1/2" groups at 25 yards, It should be a shooter. Practice the double tap often and keep it loaded with a +P+ level 115 gr. JHP or a +P 124 gr. JHP. Because placement is almost everything and recovery speed between shots will make up the difference.

I think the SEALs use 147 gr subsonic ammo in their 9mm P226's. There was a bunch of it on sale surplus at www.ammoman.com. Could've been machinegun ammo but I doubt it. I agree though that the caliber snobs have given 9mm a bad rap. Perhaps it's to justify their plunking down a grand or more on a .45 they probably won't carry because they don't want to get any scratches on it.

Now I think they're carrying Glock 23s in .40 (can anybody say KABOOM?).

I would tend to agree, Glocks have a serious tendencies to go kaboom especially the .40's and the .45's most people argue it's because of reloaded ammo and that is most certainly the case if a few circumstances.

On the other hand I have seen 4 G23 and 5 G21's go kaboom at the range over the years I know the people well how owned these guns "I have shot at the same club for 9 years" and I know for a 100% fact they where all using brand new factory ammo.

Yet another reason not to buy a pistol with a non supported chamber, IMO Glock has done a EXCELLENT job over the years at coveringup all the kB's with their gun's some would argue out of millions of gun's the percentage is small I say to that I have seen a average of 1 Glock per year explode.

I am not trying to flame Glock I think Glock makes a fine pistol "if you buy a after market barrel" I would just like to see them acknowledge the fact there is a danger with their big bores and solve this issue.

But unfortunately I doubt it will ever happen considering it would murder their sales and the retro fit would cost them million's

 

[DanaT]

There has always been a bias against the 9mm because it shoots a lighter, faster bullet that will generate more kinetic energy than standard .45 acp JHP's. Sometimes, the kinetic energy equation is questioned because caliberites believe it unfairly tilts in the 9mm's favor. In IPSC they developed a formula that they felt corrected this by accentuating bullet weight to momentum: Bullet wt. X Velocity / 1000 gives a calibers Power Factor and while IT IS math, the kinetic equation is physics, based on Einsteins theory. Remember E=MC2. Well, it works with bullets.

Damn. Thats one fast bullet since we are now converting mass into energy. The "C" is the speed of light, roughly 3x10^8 m/sec.

Not to argue here, but Einsteins theory came much later than clasical [particle] physics.

I think you actually meant to say e=mv^2 specifically, ke= m* v^2.

The e-mc^2 is actually how much energy a mass turns into when it matches the speed of light.

-Dana

 

[NiK]

There has always been a bias against the 9mm because it shoots a lighter, faster bullet that will generate more kinetic energy than standard .45 acp JHP's. Sometimes, the kinetic energy equation is questioned because caliberites believe it unfairly tilts in the 9mm's favor. In IPSC they developed a formula that they felt corrected this by accentuating bullet weight to momentum: Bullet wt. X Velocity / 1000 gives a calibers Power Factor and while IT IS math, the kinetic equation is physics, based on Einsteins theory. Remember E=MC2. Well, it works with bullets.

Damn. Thats one fast bullet since we are now converting mass into energy. The "C" is the speed of light, roughly 3x10^8 m/sec.

Not to argue here, but Einsteins theory came much later than clasical [particle] physics.

I think you actually meant to say e=mv^2 specifically, ke= m* v^2.

The e-mc^2 is actually how much energy a mass turns into when it matches the speed of light.

-Dana

LOL. Now here is a man with a black belt in tact-fu.

 

[Forsaken]

There has always been a bias against the 9mm because it shoots a lighter, faster bullet that will generate more kinetic energy than standard .45 acp JHP's. Sometimes, the kinetic energy equation is questioned because caliberites believe it unfairly tilts in the 9mm's favor. In IPSC they developed a formula that they felt corrected this by accentuating bullet weight to momentum: Bullet wt. X Velocity / 1000 gives a calibers Power Factor and while IT IS math, the kinetic equation is physics, based on Einsteins theory. Remember E=MC2. Well, it works with bullets.

Damn. Thats one fast bullet since we are now converting mass into energy. The "C" is the speed of light, roughly 3x10^8 m/sec.

Not to argue here, but Einsteins theory came much later than clasical [particle] physics.

I think you actually meant to say e=mv^2 specifically, ke= m* v^2.

The e-mc^2 is actually how much energy a mass turns into when it matches the speed of light.

-Dana

Dana, I have been around this game for a long time, and I'm sure you understand that there are several interpretations fo the formula for kinetic energy, based on units of mass. Ballisticians use the one I furnished and have been for the 5 years that I've been reloading. Any reloading manual will furnish the same formula.
I don't quite understand, other than maybe an attempt to nitpick, your questioning my statement about power factor. This is not a physical formula for momentum, as used by IPSC. MV x BW / 1000 does not conform to any physical formula based on KE or momentum and why I stated it is math, but not physics.

I used Einstein for the reason I thought most would understand, because of the E=Mc2 formula and we should all know about Sir Isaac Newton if we know anything about physics. If you really need a math lesson, here is a transcrition E (KE) = M (bullet Wt. in grs.) X c2 (since we know bullets don't travel at light speed, will just plug in velocity squared )

The Ballisticians KE formula is used because it provides a shortcut via the divisor, unless you want to formulate bullets by decimal units of a pound or fractions of a pound.

BTW, if you do, the grain = 1/7000 th of a pound if you would like to use a standard equation. I am glad however that you are educated. I am not educated beyond my own intelligence, however.

Regards.

 

[therooster]

i say SCREW THE DEBATE....

take both rounds... look at them... tell me if 3mm in diamiter is going to help me sruvive being hit.

.380, 9mm, .40, .45..... its all the same when you get hit with 5-10 of 'em. You will not survive.

 

[manygunner]

Actualy you may survive being hit by as many as 30. There are documented cases of this happening. Where you hit is as important as what you hit with. For my money the 9mm is better because it allows more accurate shot placement at longer ranges and has high v which translates to high Ke. The other part of the problem is the terminal ballistics of the round. This is where expansion and other such effects get involved. I prefer the 9mm because if the worst happens it will shatter a pelvis due to the high velocity energy aspects. It has been found that lower velocity rounds such as .45 and .40 will not do that reliably. I will still do the 2 to the center of mass/chest first but have been told to go for pelvis/lower abdomen next. Head is too difficult to hit in actual combat as it is weaving and a small target. Hits to pelvis/lower abdomen should incapacitate due to the pain factor involved. Would you like to feel your bladder explode?

Dana is right about the formula Ke=1/2mv^2. Unfortunately the formula is not used to see how much energy a mass would have at C, but to show it is impossible. Any mass travelling at C has infinite energy and also corespondingly infinite mass, that is why speed of light travel is not possible for anything with a rest mass. The Lorentz transforms show us why, but enough theoretical physics lessons.

 

[crzybotr]

it's the individual that matters most when the poopie hits the fan, not the difference of a few millimeters. shoot what you're confident and competent with.

 

[The Drew]

I think we are overly obsessed with the "one shot stop" myth... That .40 and .357mag have the best "one shot stop" stats is nothing more than statistics spinning the facts...

I have an xd in .40 Why? because at the time I bought it the AWB was in effect and I could only have 10 rounds... So I chose the larger calibre. Now that the AWB is ended and factory hi caps are available I carry a 9mm. Why? because I'd rather have those 5 extra rounds, or 3 extra if you consider 12 round .40 mags. and when push comes to shove the .40 is only marginally "better" ballistically as well as the .357sig. I won't carry my 1911 for many reasons, it's too big to conceal comfortably, I only get 7+1 reliable feeding of HP's, and I don't trust my particular model's cocked and locked carry... (my manual safety is VERY weak... I.E. easy to unlock...)

Bottom line... carry what you are comfortable with... if you feel safe with a .32auto... then by all means go ahead and carry that... the reality is that any gun is better than no gun... (as long as it's loaded...)

 

[SLCDave]

Just to pile on the original poster's theory... :wink:

So, since the .380 is the same diameter as a 9x19, and a 10mm is the same as a .40 S&W, is it safe to say getting shot with a .380 is relatively equal to getting shot with a 10mm?

Or can you equate a .380 to a .357 magnum? Aren't they both a 9mm bullet?

 

[The Drew]

No, you can't, however has anyone ever wondered why there are so many 9mm diameter calibers??? .38spl, .357mag, 9mm makarov, 9mm police, .380 , 9x19, .38 super, .357sig, 9x21 and 9x23 varieties...

I'm sure that there are more...

all of these calibers exhibit different ballistics depending on the case size (which in turn dictates max bullet weight)

would anyone here honestly say that any of these calibers is truly not defensive weapon worthy???

Remember that in a ccw situation you would most likely NOT be encountering armored foes. And I think a headshot by any of these should be sufficient to put ANY man down...

 

[manygunner]

No, you can't, however has anyone ever wondered why there are so many 9mm diameter calibers??? .38spl, .357mag, 9mm makarov, 9mm police, .380 , 9x19, .38 super, .357sig, 9x21 and 9x23 varieties...

I'm sure that there are more...

all of these calibers exhibit different ballistics depending on the case size (which in turn dictates max bullet weight)

would anyone here honestly say that any of these calibers is truly not defensive weapon worthy???

Remember that in a ccw situation you would most likely NOT be encountering armored foes. And I think a headshot by any of these should be sufficient to put ANY man down...

The answer to the first question is people are notorious tinkerers and always think they can come up with something better. That is why the US military is using a fairly useless 5.56mm rifle round when studies done by the british earlier pointed out that 7mm is optimal for a service rifle. Now they are finaly getting on the bandwagon with the 6.8mm.

To answer another point there are documented cases where assailants continued to come at an officer despite multiple hits, including head and neck shots. The assailant in the most dramatic case was not on any drugs and managed to kill the surviving officer's partner and injure severely the surviving officer with a contact weapon. Your idea that a head shot will stop is WRONG!!! The target area that will incapacitate on a head shot is quite small. It is exteremely hard to hit when a target is moving and dodging (a natural reflexive action in a hostile situation, the body knows the brain is important) and even then might NOT incapacitate immediately. The brain is surrounded by pretty hard bone and documented cases exist where head shots with a .45 just bounced around the outside of the skull under the skin. Most training is done at stationary targets that are not shooting back. Even lethal wounds may take 10-20 seconds to shut an assailant down. I can empty a high capacity handgun with accurate fire discipline, reload and do it again in less time. Also people who are down may get up as the prone position aids in increasing blood flow and blood pressure to the brain. There are documented cases of assailants feeling better when they went down and getting up to catch people unawares.

Your view on body armourbeing worn by an assailant is also in error. As most law enforcement people know, the chance that an assailant is wearing body armour is increasing dramatically. Some large city police departments are actually teaching to not shoot the center of mass/chest, but the lower abdomen to avoid possible body armour coverage. Also assailants now come with partners and, in many cases, high tech toys to coordinate in robberies (think about that if you are caught in a 7-eleven or restaurant hold up), coordinating tactics and communications with back up men on the inside and outside.

As "M" said in one of Ian Fleming's James Bond novels, "Shooting the hell out of a piece of cardboard does not prove a thing."