A question for gun experts

[Thomas Veil]

My family and I were discussing an old Columbo episode in which the victim was killed by a particular caliber of bullet. The suspect that Columbo tailed for the entire episode (Robert Culp), though he owned handguns, owned none of the caliber that was used in the murder.

At the end, Columbo proves the murderer guilty by discovering an item hidden in a lamp. "A calibration converter," he says. "That was a sweet touch. I never would have thought of that." And we see that the calibration converter is a cylindrical device which slides into the barrel of a handgun.

Now, one of us in the discussion is studying criminal justice, and neither he nor the rest of us had ever heard of a calibration converter. Nor could we figure out how, if this device slips into the barrel of a gun, it isn't violently ejected when one fires the weapon.

I Googled this term, and most of what I came up with was either electronics, or other references to that Columbo episode. I even checked a handgun site and found nothing about it. Only one web page made a passing mention of it, and I think they were talking guardedly about using weapons for illegal purposes.

So does anybody know about calibration converters? I'm just curious, because if it weren't for the reference above, I'd be tempted to pass it off as a Hollywood scriptwriter's invention. And if they're real, how do you keep them from ejecting when the gun is fired? Does this device have any legitimate purposes, or is it mainly designed to deceive law enforcement? If the latter, how come you don't hear more about criminals using them?

[WinterMute]

Yes it a real item, Heckler and Koch supply a converter to the MP5 and others that take the caliber down to .22 for room clearence, stops the 9mm rounds from going through walls and killing civillians.

It's as you describe, a sleeve that fits into the barrel and a different feed mechanism.

[CorvusCamenarum]

Actually, such a device was mentioned in Tom Clancy's Without Remorse . The protagonist used one to convert a .45 into a .22. Yes, I know it's a book and a work of fiction at that, but Clancy is usually very good in being as realistic as possible when it comes to technological matters and whatnot.

[iLikeMyiMac]

Actually, such a device was mentioned in Tom Clancy's Without Remorse . The protagonist used one to convert a .45 into a .22. Yes, I know it's a book and a work of fiction at that, but Clancy is usually very good in being as realistic as possible when it comes to technological matters and whatnot.
I read that book and really liked it.

One reason to use one is that since .22 rounds are really cheap you can convert your .45 down to one to practice and save money.

[Nickygoat]

Yes it a real item, Heckler and Koch supply a converter to the MP5 and others that take the caliber down to .22 for room clearence, stops the 9mm rounds from going through walls and killing civillians.

It's as you describe, a sleeve that fits into the barrel and a different feed mechanism.
For a lecturer in music(?) you seem to know a lot about this :D. Much call for it with your students? :p

[applekid]

Not to hijack this thread, but what do the differences in calibers of bullets do?

I was under the impression that the bigger the caliber, the less likely it's to pierce armor. For example, in Rainbow Six (the game), the 9mm MP5's don't easily kill your opponents quickly when you hit them at the torso and, they have body armor. But, take something like an M16 with its 5.56, it pierces right through and is almost always one-shot-one-kill.

Also, I've heard on the news, or read in books or articles, the 7.62 or 5.56 are usually seen as deadly. So, my info is not just based on video games! :p

Then taking another look at the actual bullets, it seems like the 9mm is blunt and the 5.56 or 7.62 are pointier. So, it's more about the shape, then?

Then you've got your .22, .45, .50, etc. calibers... (American measurements, I assume? Are we measuring those in inches or what?)

Explain, gun experts!

[WinterMute]

For a lecturer in music(?) you seem to know a lot about this :D. Much call for it with your students? :p

Nah, that's what the aikido's for.... :eek:

My ex-brother-in-law was a Royal Marine, and I know a couple of UK special forces types from the martial arts circuit, I've done a couple of SAS training days and courses, mainly for the unarmed stuff, but also for weapons and tactics.

I know UK schools are getting more violent, but I don't think firearms are the answer just yet.

[Nickygoat]

Not to hijack this thread, but what do the differences in calibers of bullets do?

I was under the impression that the bigger the caliber, the less likely it's to pierce armor. For example, in Rainbow Six (the game), the 9mm MP5's don't easily kill your opponents quickly when you hit them at the torso and, they have body armor. But, take something like an M16 with its 5.56, it pierces right through and is almost always one-shot-one-kill.

Also, I've heard on the news, or read in books or articles, the 7.62 or 5.56 are usually seen as deadly. So, my info is not just based on video games! :p

Then taking another look at the actual bullets, it seems like the 9mm is blunt and the 5.56 or 7.62 are pointier. So, it's more about the shape, then?

Then you've got your .22, .45, .50, etc. calibers... (American measurements, I assume? Are we measuring those in inches or what?)

Explain, gun experts!
5.56, 7.62 and 9 are all mm. .22, .45, .50 are inches. The power is to do with velocity. Weight of ammunition has an effect as well. 5.56 and 7.62 are usually rifle ammunition (usually military or miltary style). .45 and .50 are handgun ammo. The exception being .50 cals you see mounted on Humvees and helicopters. .22 is a low calibre, lightweight rifle weapon with limited power and range used for hunting (animals not men).

[applekid]

5.56, 7.62 and 9 are all mm. .22, .45, .50 are inches. The power is to do with velocity. Weight of ammunition has an effect as well. 5.56 and 7.62 are usually rifle ammunition (usually military or miltary style). .45 and .50 are handgun ammo. The exception being .50 cals you see mounted on Humvees and helicopters. .22 is a low calibre, lightweight rifle weapon with limited power and range used for hunting (animals not men).

The smaller calibers means they're lighter making it easier to launch at higher velocities and making them deadlier, correct?

And of course there's the exceptions such as the .50 which are deadly as vehicle-mounted weapons.

Thanks for the explanation. It makes sense. :)

[rainman::|:|]

To further explain, you can get handguns down to to smaller callibers, but it's fairly pointless as anything less than a 22 isn't going to do much of anything. 22 would be a good home-defense, would-tear-open-a-kneecap weapon. It goes up from there, I would say .45 is a really bad choice for most handgun owners, because even if it's compensated, the recoil would screw your aim... Anyone considering a handgun should go to a shooting range and try a couple out to see what you're comfortable with. Getting too large a caliber will do no good.

[Nickygoat]

The smaller calibers means they're lighter making it easier to launch at higher velocities and making them deadlier, correct?

Thanks for the explanation. It makes sense. :)
No that's the wrong way round. They do have higher velocities but a lower mass. Force = mass x velocity. Rifles can fire heavier bullets because the barrels can withstand more pressure. See here (http://www-medlib.med.utah.edu/WebPath/TUTORIAL/GUNS/GUNBLST.html) for a more technical explanation. Don't believe everything you see in videogames ;)

[Kwyjibo]

No that's the wrong way round. They do have higher velocities but a lower mass. Force = mass x velocity. Rifles can fire heavier bullets because the barrels can withstand more pressure. See here (http://www-medlib.med.utah.edu/WebPath/TUTORIAL/GUNS/GUNBLST.html) for a more technical explanation. Don't believe everything you see in videogames ;)

force = mass x acceleration ....

[Nickygoat]

force = mass x acceleration ....
B***** :D. It's been a while since I did physics.

[pseudobrit]

The smaller calibers means they're lighter making it easier to launch at higher velocities and making them deadlier, correct?

And of course there's the exceptions such as the .50 which are deadly as vehicle-mounted weapons.

Thanks for the explanation. It makes sense. :)

The makeup of a bullet is more critical than its caliber. A hollowpoint is going to behave differently than an armour-piercing round. In some cases, a small armour-piercing round is ideal and in others they're nearly worthless. Generally speaking, a soft target needs a soft bullet.

[absolut_mac]

force = mass x acceleration ....

???

The bullet is decelerating virtually the instant it leaves the barrel.

I think that force = mass X velocity is more accurate because how much force depends on exactly how fast the bullet is traveling at the point of impact mutliplied by its mass, which remains virtually unchanged once it leaves the barrel i.e. there will be a lot more force involved a short distance from the barrel than 1 mile from it.

As for the size and the weight of the bullet. It requires a lot less energy to launch a low mass at a high velocity than a much heavier mass to the same velocity. Coupled with the fact that a low mass bullet will dissipate its energy a lot faster than a heavier one. Another added advantage is that because less energy is required, the gun will kick less and hence be a lot easier to control.

Just to put things in perspective, an average 9mm bullet weighing 115 grains usually has a muzzle velocity of around 400meters/second. An average 230 grain 45 caliber bullet has a muzzle velocity of around 280meters/second. A 50 grain 5.56mm bullet has a sizzling muzzle velocity of around 1000meters/second. And NATO's old round, the 125 grain 7.62mm has a muzzle velocity of around 800meters/second.

Maybe somebody can post the conversion of grains to grams.

[Mechcozmo]

I was under the impression that the bigger the caliber, the less likely it's to pierce armor. For example, in Rainbow Six (the game), the 9mm MP5's don't easily kill your opponents quickly when you hit them at the torso and, they have body armor. But, take something like an M16 with its 5.56, it pierces right through and is almost always one-shot-one-kill.

Also, I've heard on the news, or read in books or articles, the 7.62 or 5.56 are usually seen as deadly. So, my info is not just based on video games! :p

Then taking another look at the actual bullets, it seems like the 9mm is blunt and the 5.56 or 7.62 are pointier. So, it's more about the shape, then?

Then you've got your .22, .45, .50, etc. calibers... (American measurements, I assume? Are we measuring those in inches or what?)

The barrel of a gun has a lot to do with how the gun hits and kills. If the barrel has grooves in it, the bullet will spin (like a football) and be more accurate and deadly, for when it hits a target it rips through into their insides. An M-16's round actually tumbles through the air so that when it hits a target, it destroys the targets insides.

9mm, 5.56mm, .22 caliber, all refer to diameter. Tanks can have a 105mm gun. A .45 caliber pistol means the bullet is .45 inches in diameter.

That's why a .45 and a .50 are so devastating-- they are simply larger bullets. In WWII, B-17s had a number of .50 cal guns on them. They would fire back at fighters incoming. If they contacted an enemy fighter in the right spot they could sometimes blow the wing clear off.

[applekid]

Whew, I'm learning more about guns than I needed to know! :D

It's all been an educational experience though, so thanks everyone. And I think I hijacked Thomas Veil's thread now. Whoops...

[Nickygoat]

???

The bullet is decelerating virtually the instant it leaves the barrel.

I think that force = mass X velocity is more accurate because how much force depends on exactly how fast the bullet is traveling at the point of impact mutliplied by its mass, which remains virtually unchanged once it leaves the barrel i.e. there will be a lot more force involved a short distance from the barrel than 1 mile from it.

As for the size and the weight of the bullet. It requires a lot less energy to launch a low mass at a high velocity than a much heavier mass to the same velocity. Coupled with the fact that a low mass bullet will dissipate its energy a lot faster than a heavier one. Another added advantage is that because less energy is required, the gun will kick less and hence be a lot easier to control.

Just to put things in perspective, an average 9mm bullet weighing 115 grains usually has a muzzle velocity of around 400meters/second. An average 230 grain 45 caliber bullet has a muzzle velocity of around 280meters/second. A 50 grain 5.56mm bullet has a sizzling muzzle velocity of around 1000meters/second. And NATO's old round, the 125 grain 7.62mm has a muzzle velocity of around 800meters/second.

Maybe somebody can post the conversion of grains to grams.
14.3 grains = 1 gram. Long barreled weapons have less kick than short barreled ones. Muzzle velocity has very little to do with effect.
The barrel of a gun has a lot to do with how the gun hits and kills.
"If the barrel has grooves in it, the bullet will spin (like a football) and be more accurate and deadly, for when it hits a target it rips through into their insides. An M-16's round actually tumbles through the air so that when it hits a target, it destroys the targets insides." All barrels have grooves - this is how the bullet flies straight (ish). Low range weapons, like the M-16, are deliberately designed so that the bullet "tumbles". The bullet tumbling carries a lot of kinetic energy and will cause a lot of damage once it hits a target. It is not, however, particularly accurate over a long distance. For that you need a well grooved barrel and heavy ammunition. The bullet does not tumble over distance so you are relying on a well placed shot ie. along the "T" from the forehead across the brain, down through the major internal organs, to achieve a "kill" shot. The bullet has less effect than the trauma to the major organs.

[Teddy Noback]

I'm not sure how many of you are from over seas, but there is a desire among the anti-gun lobby in America to "fingerprint" all guns at the time of manufacture. It's based upon the mistaken belief that police could solve more gun-related crimes because there would be a database of ballistic "fingerprints" that would help trace the gun. It is my understanding that it only takes a metal rod (not the kind for cleaning guns) to scrape the inside of a barrel, and the finger print is ruined. I don't if this comment is on topic, but your Colombo story made me think of it. Thinking people should find this obvious, but then again . . .

[saabmp3]

???

The bullet is decelerating virtually the instant it leaves the barrel.

I think that force = mass X velocity is more accurate because how much force depends on exactly how fast the bullet is traveling at the point of impact mutliplied by its mass, which remains virtually unchanged once it leaves the barrel i.e. there will be a lot more force involved a short distance from the barrel than 1 mile from it.


Although it sounds like you know alot about bullets and guns, but, F=ma. Deceleration is acceleration, but negated. so, the force of a bullet is exactly when it leaves the barrel of the gun. Basically, take the initial speed, V0 = 0MPH and the V1 = 400MPH? (I don't know much about guns, just physics). From that, given delta t of the travel you can calculate the acceleration of the bullet. Then multiply this by the mass and you get the instantaneous force of the bullet. From there, you say the bullet is decelerating (due to resistance in some form, air, the wall, my leg, etc). So, do the same calculation for a different delta t, but with a negative acceleration. Then, you get a negative force. Add this negative force to the initial force from where the bullet left the barrel of the gun and you get the new instantaneous force. When the bullet stops, you should have 0 N of force if you have done all of your calculations correctly.

BEN

[Thomas Veil]

Whew, I'm learning more about guns than I needed to know! :D

It's all been an educational experience though, so thanks everyone. And I think I hijacked Thomas Veil's thread now. Whoops...No problem. I'm learning more than I asked about. Although the question remains: how is the calibration converter held in place when the gun is fired? Does it screw in somehow?

Thanks to all who've responded so far.

[absolut_mac]

Deceleration is acceleration, but negated.

Hmm, it's been many decades since my last science and math classes, but I clearly remember the term velocity being used. The main reason being is that in certain situations terminal velocity is reached, and then the object is neither accelerating or decelerating - eg someone jumping out a plane - and will continue to do so until it collides with something.

I may be wrong about the exact term, so I'll have to check with my NASA aerospace friend to see what the preferred term is today.

[superbovine]

Although it sounds like you know alot about bullets and guns, but, F=ma. Deceleration is acceleration, but negated. so, the force of a bullet is exactly when it leaves the barrel of the gun. Basically, take the initial speed, V0 = 0MPH and the V1 = 400MPH? (I don't know much about guns, just physics). From that, given delta t of the travel you can calculate the acceleration of the bullet. Then multiply this by the mass and you get the instantaneous force of the bullet. From there, you say the bullet is decelerating (due to resistance in some form, air, the wall, my leg, etc). So, do the same calculation for a different delta t, but with a negative acceleration. Then, you get a negative force. Add this negative force to the initial force from where the bullet left the barrel of the gun and you get the new instantaneous force. When the bullet stops, you should have 0 N of force if you have done all of your calculations correctly.

BEN

you're correct, but i imagine everyone is wondering what the hell delta t is because you did not elaborate on it. ;) you also didn't explain what instantaneous force is. i.e. i am sure everyone is confused by you explaination unless they took physics and calculus. ;) but yeah, you are correct.

[absolut_mac]

No problem. I'm learning more than I asked about. Although the question remains: how is the calibration converter held in place when the gun is fired? Does it screw in somehow?

Some automatic handguns have complete interchangeable barrel/slide assemblies to facilitate a change in caliber, and some revolvers just require half moon clips e.g. a 38 special will require the half moon clips in order to take 9mm bullets. Because the diameter of both bullets is identical, no other change is required.

Also, if I recall correctly, Ruger made same revolvers where both the chamber and the barrel (which was screwed in) were swapped out in order to achieve the same thing.

[iLikeMyiMac]

force = mass x acceleration ....
right but Kinetic Energy = .5mv^2 so a higher speed bullet has more kinetic energy.

LOL at the people who get their information about guns from video games.

Here's more info on a caliber converter I found on google about how to do it with a glock. http://www.advantagearms.com/

[Mechcozmo]

No problem. I'm learning more than I asked about. Although the question remains: how is the calibration converter held in place when the gun is fired? Does it screw in somehow?

Essentially, yes it is screwed in to the gun. It isn't a "pop in, pop out" deal mind out because it isn't just the barrel but the feed mechanisms also need to be converted slightly...

[saabmp3]

you're correct, but i imagine everyone is wondering what the hell delta t is because you did not elaborate on it. ;) you also didn't explain what instantaneous force is. i.e. i am sure everyone is confused by you explaination unless they took physics and calculus. ;) but yeah, you are correct.

Hehe, yeah, I'm an engineer. (Calc, physics, modern physics, theory of relativity, quantum physics are all in my background)

For those here who are a tad confused:

Delta is mean a change (in laymen's terms). Delta t would be the change in time from 0 to 1.

Thanks superbovine for backing me up!

BEN

[topicolo]

Hmm, it's been many decades since my last science and math classes, but I clearly remember the term velocity being used. The main reason being is that in certain situations terminal velocity is reached, and then the object is neither accelerating or decelerating - eg someone jumping out a plane - and will continue to do so until it collides with something.

I may be wrong about the exact term, so I'll have to check with my NASA aerospace friend to see what the preferred term is today.

You must be thinking of the momentum and kinetic energy equations. iLikeMyiMac already mentioned that
kinetic energy = 0.5mv^2

but

momentum = mv

What really impacts the penetrating ability of the bullet is the momentum and since mass and velocity are directly related to the momentum, you can increase penetration by increasing the mass or the velocity.

Here's the interesting thing: if you want the bullet to go faster, you need a LOT more energy, since the v is squared in the kinetic energy equation and you'll need a lot more gunpowder. The solution is to increase the mass of the bullet, hence the increase in caliber.

How's that for a non-physics major? ;)

[Lacero]

I was under the impression that the bigger the caliber, the less likely it's to pierce armor. For example, in Rainbow Six (the game), the 9mm MP5's don't easily kill your opponents quickly when you hit them at the torso and, they have body armor. But, take something like an M16 with its 5.56, it pierces right through and is almost always one-shot-one-kill.

Since this M16 bullet would be travelling sideways through most of its path in an abdominal wound, it would be expected to cut a swath over three times the dimension made by the bullet travelling point forward. In addition to the larger hole in organs from the sideways-travelling bullet, the tissue surrounding the bullet path will be stretched considerably from temporary cavitation. Actual damage from the stretch of cavitation can vary from an almost explosive effect, widely splitting a solid organ such as the liver, or a hollow one such as the bladder if it is full at the time it is hit, to almost no observable effect if the hollow organs (such as intestines) when hit contain little liquid and/or air.

[2jaded2care]

The caliber conversion kits I've seen pics of seem to consist of replacement barrel/slide assemblies and magazines. (Don't have one myself, though.) Don't see how a simple tube inserted into a regular barrel would necessarily be a good idea, but I'm no gunsmith either.

To further explain, you can get handguns down to to smaller callibers, but it's fairly pointless as anything less than a 22 isn't going to do much of anything. 22 would be a good home-defense, would-tear-open-a-kneecap weapon. It goes up from there, I would say .45 is a really bad choice for most handgun owners, because even if it's compensated, the recoil would screw your aim... Anyone considering a handgun should go to a shooting range and try a couple out to see what you're comfortable with. Getting too large a caliber will do no good.

The .45 recoil depends on the pistol design and its weight. (The HK USP design does a good job of "cushioning" recoil, though I prefer a 1911.) A full-size, metal frame .45 isn't bad to me. OTOH, a compact, lightweight polymer (Glock) didn't give me warm fuzzies.

Also people seem to get "used to" the recoil the more they shoot, so if you're on limited income you don't want to get stuck with a small-caliber pistol either. I'd rather have a .40 or .45 for stopping power than a .22 or even 9mm. But to each his or her own.

[Lord Blackadder]

Warning: Long winded post.

I never saw that Columbo, and as far as a "calibration" converter, hmm, I'm a bit skeptical. There is no one device that wil instantly alter a semi-auto pistol's caliber AFAIK.

However, there are many kits available to quickly convert various handguns from one caliber to another. It depends on which calibers are involved, but almost all include a different barrel, magazine and several parts which allow a different sized round to feed through a semi-auto. doing a caliber conversion on a revolver is simpler, usually involving just two parts: a new barrel and cylinder.

A popular round to convert to is a .22LR, because it is cheap. However, people who think that a .22LR is effective as a self defense weapon are in for a rude awakening; while it can kill, it has almost no stopping power against a human target, and requires multiple well-placed shots for incapacitation. I would not want to get shot with a .22 pistol, but I wouldn't want to try stopping an assailant with one either.

Forget whatever video games have taught you, since video game guns are completely made up; they exist as a series of values for damage/range/accuracy etc. They rarely account for things like ballistic trajectories and whatnot. And they're not real. :D

As far as the ammo effectiveness goes, pistol bullets are very effective at close range because of the large caliber bullets and the properties of hollow/soft points. Calibers like .40 S&W, .44/.357 Magnum, .45 and .50 Action Express (Desert Eagle) are big and can knock down a target and create large wound channels with soft/hollow point rounds. However, pistol bullets travel relatively slowly, with muzzle velocities in the 800-1000+fps range. This limits their effective range. They are also relatively useless against body armor at anything but extremely close range. All modern handguns (indeed all modern small arms) use rifling.

BTW, the .50AE round fired by the Desert Eagle is much less powerful than the .50BMG (Browning Machine Gun) bullet fired by military machine guns like the M2 or anti-vehicle rifles like the Barret series. They are the same caliber, but an entirely different class of capability.

On the other hand, high-power rifle rounds like .30-06, 7.62x51 NATO or 7.92x57 Mauser are smaller caliber (7.62mm is ~ .30 caliber) but have much more propellant than a pistol cartridge and travel at velocities in exess of 2700fps, giving them far more penetration and range. They are much too powerful to use in a handgun, as they would recoil too much to aim, even more than a magnum round. Also, the common military round is a "full metal jacket", a copper/zinc/tin bullet with a lead core that won't expand like many softpoint/hollow point pistol rounds. This enhances penetration, and can defeat body armor and unarmored/lightly armored vehicles. In the right hands these weapons are very accurate at over 1000 meters, and can kill from over a mile away in the right conditions.

Finally we have small caliber military rounds like the 5.56 NATO (aka .223 Remington) or soviet 5.45mm. They have an even higher velocity than the rifle rounds ( often 3000+fps), but are very small caliber. A .22LR bullet and .223 are almost the same diameter, but the .223 travels a lot faster, and thus has more energy. Another feature of these small caliber high-velocity rounds is that, because of their light weight, they tend to tumble when they strike something. This produces a wound channel much larger than the actual caliber of the bullet. Unfortunately, this same light weight makes them much less effective at longer ranges; the bullet has a lot less energy at 500+ meters than a full size rifle round, and becomes more influenced by wind. This makes them less useful for sniping.

There has been an ongoing debate in the military whether the 5.56mm round is the best choice for the modern battle rifle. M-16s and similar weapons that fire the small caliber round are lighter, have less recoil which allows for more accurate rapid fire, and soldiers can carry more ammo because it is smaller. However, reports from recent wars indicate that in some situations the higher power of the big rifle caliber is preferred because the small rounds don't always tumble; sometimes an enemy might take several rounds to non-lethal areas that go clean through and cause flesh wounds but not incapacitation. U.S. Special forces often use variants of the M-16/M-4 or old M-14 that fire the full size 7.62x51 round, which seems to lend some credence to this rumor.

Sorry I wote a book. :o

[aloofman]

You must be thinking of the momentum and kinetic energy equations. iLikeMyiMac already mentioned that
kinetic energy = 0.5mv^2

but

momentum = mv

What really impacts the penetrating ability of the bullet is the momentum and since mass and velocity are directly related to the momentum, you can increase penetration by increasing the mass or the velocity.

Here's the interesting thing: if you want the bullet to go faster, you need a LOT more energy, since the v is squared in the kinetic energy equation and you'll need a lot more gunpowder. The solution is to increase the mass of the bullet, hence the increase in caliber.

How's that for a non-physics major? ;)

I was reading all the way through this thread and ready to point out that it's the momentum equation that everyone seems to be grasping for, and someone beat me to it.

It's the tremendous momentum given to the bullet that makes it deadly, a combination of the mass and velocity, but mostly it's the velocity. A penny dropped off a skyscraper can't kill you -- even if it hits you on the head -- because even at terminal velocity, it's mass is so low that it doesn't have much momentum. But a brick dropped from 30 feet can kill you because it has far more momentum. Similarly a freight train going 5 mph will win a collision with a speeding car any day. Guns overcome the bullets' small mass through tremendous velocity, but bigger bullets don't always have greater velocities.

As the others said, the type of bullet really matters though. The simple physics equations only describe the momentum with which the bullet hits an object. It gets far more complicated to explain what the impact does to human tissue. Weapon makers have been fiddling with those factors ever since guns were first invented.

My understanding is that many of the guns used by special forces teams are of smaller caliber mainly because they make the ammo more compact to carry. Most of the time their missions involve putting the enemy out of commission fast, not necessarily to blow big holes in them like with a .45. Someone can correct me if I'm wrong on that.

[Mechcozmo]

Warning: Long winded post.

I never saw that Columbo, and as far as a "calibration" converter, hmm, I'm a bit skeptical. There is no one device that wil instantly alter a semi-auto pistol's caliber AFAIK.
Sorry I wote a book. :o
It was a caliber converter... not a calibration converter...

And it was a very good description of what and why bullets, uh, work. Kudos to you on knowledge of destructive forces. ;)

[krimson]

I was completely confused at the early posts. I have a 22 conversion on my 1911, it's cheaper to use at the range. the assembly is a complete slide, barrel and a modified magazine.

In regards to 5.56mm rounds tumbling in the air, I believe that it's a misconceptioon. The "tumbling" effect doesn't really come into play until it enters something like a human body. Having a bullet tumbling in the air reduces accuracy, and why would you want a less accurate rifle in combat? My Colt AR (http://home.earthlink.net/~krimson122/images/tammy01.jpg) uses a 1 in 10 twist, because i use heavier bullets (62-65 grain). It's useful for sniping (varmit hunting) under 200 yds. Using a heavy bullet in a barrel that has a twist rate for a lower weight would decrease accuracy, and vice versa. Anything beyond 200 yds, i'd definately go to a higher 308 caliber.

Hope that makes some sense, since I haven't finished my morning cup o java.

[Lord Blackadder]

I was completely confused at the early posts. I have a 22 conversion on my 1911, it's cheaper to use at the range. the assembly is a complete slide, barrel and a modified magazine.

In regards to 5.56mm rounds tumbling in the air, I believe that it's a misconceptioon. The "tumbling" effect doesn't really come into play until it enters something like a human body. Having a bullet tumbling in the air reduces accuracy, and why would you want a less accurate rifle in combat?

Exactly. Like I said, the 5.56 round will not tumble UNTIL it strikes something (although again there is a debate as to whether this happens as often as it is supposed to). When a bullet is tumbling after it leaves the barrel, you either have a bad barrel or are firing incorrect caliber ammunition.

A marine friend of mine has a Bushmaster XM-15 (AR-15 clone) which is extremely accurate with open sights at 300 meters (if you do your part). On the other hand, so is my Enfield No.4 Mk 1 or Yugo M48A - there is just more recoil, and they make bigger holes! Actually, the light recoil of the AR series really helps when a squad is trying to lay down a lot of accurate fire fast - It's hard to imagine doing that with a Garand or Tokarev SVT-40 firing the full sized stuff.

I've been looking for a decent WWII/Korea era 1911 for my collection, but I'm mosty into rifles. My experience with pistols is limited to my friend's Glock 17 and Taurus PT99AF (a Beretta 92F copy - nice gun BTW).

[Nickygoat]

I was completely confused at the early posts. I have a 22 conversion on my 1911, it's cheaper to use at the range. the assembly is a complete slide, barrel and a modified magazine.

In regards to 5.56mm rounds tumbling in the air, I believe that it's a misconceptioon. The "tumbling" effect doesn't really come into play until it enters something like a human body. Having a bullet tumbling in the air reduces accuracy, and why would you want a less accurate rifle in combat? My Colt AR (http://home.earthlink.net/~krimson122/images/tammy01.jpg) uses a 1 in 10 twist, because i use heavier bullets (62-65 grain). It's useful for sniping (varmit hunting) under 200 yds. Using a heavy bullet in a barrel that has a twist rate for a lower weight would decrease accuracy, and vice versa. Anything beyond 200 yds, i'd definately go to a higher 308 caliber.

Hope that makes some sense, since I haven't finished my morning cup o java.
I''ll assume the tumbling quote was aimed at me :). Yes it was inaccurate to say the M-16 was designed to tumble. Rounds from an M-16 do tumble but only under certain conditions, and not all the time. I was trying to say that they tumbled when entering a target but it didn't come out very well :). There is anecdotal evidence that the Russians did design some of their weapons for this effect. The idea being that these types of weapons were issued to relatively poorly trained troops for use in close combat situations. Situations where the soldier would not have the time or inclination to properly aim a shot, and would fire indiscriminately. At short distances high accuracy is not so essential. There is another theory that says that ammunition that tumbles on contact is deliberately to cause casualties, not fatalaties, as casualties take up more of the enemy's time and resources, as well as sapping morale. To look at a comrade with a leg blown off and in distress can be more upsetting than realising they're dead. If that's completely wrong could you point me in the direction of a decent source for confirming it? thanks. And sorry for taking the whole thread off topic :D

[mactastic]

Force does indeed equal mass x acceleration, but acceleration can also be expressed and velocity^2. Thus doubling a projectile's mass will double it's force, but doubling it's velicoty will quadruple it's force.

As far as ballsitics go, others can give more detailed explanitions that I can about stopping power, energy transfer, and sectional density. But I will say that calibers by themselves are simply measurements of the diameter of the projectile. What propels them out of the barrel is a key factor as well. Just look at the difference between a .22LR round and a .22-250 round. Same bullet diameter, very different ballistics.

Also, for a given bullet, lighter equals quicker acceleration, but also quicker deceleration and more tendency to drift in the wind. Heavier bullets may leave the muzzle slower, but impact faster at the longer distances than a lighter bullet. Heavier bullets also penetrate better than lighter ones. But heavier bullets also drop more than lighter ones over the same distance because the heavier bullet is traveling slower and thus gives gravity more time to act. So a heavy round at long distance requires a huge amount of 'holdover' to put the shot where it's wanted.This means that while a .22LR is not a good long range round, neither is a .45-70 Government. Good long range rounds tend towards the middle ground.

When one looks at the differences between handgun and rifle rounds you immediately notice that rifle bullets are typically 'necked down' from a wide powder-containing area to the actual projectile itself. Handgun rounds on the other hand are usually the same diameter throughout. Handgun rounds have less powder per bullet weight than rifle rounds. The long barrel of a rifle also allows the expanding gasses more time to do their thing providing higher muzzle velocities than a comparable pistol would.

[mactastic]

I''ll assume the tumbling quote was aimed at me :). Yes it was inaccurate to say the M-16 was designed to tumble. Rounds from an M-16 do tumble but only under certain conditions, and not all the time. I was trying to say that they tumbled when entering a target but it didn't come out very well :). There is anecdotal evidence that the Russians did design some of their weapons for this effect. The idea being that these types of weapons were issued to relatively poorly trained troops for use in close combat situations. Situations where the soldier would not have the time or inclination to properly aim a shot, and would fire indiscriminately. At short distances high accuracy is not so essential. There is another theory that says that ammunition that tumbles on contact is deliberately to cause casualties, not fatalaties, as casualties take up more of the enemy's time and resources, as well as sapping morale. To look at a comrade with a leg blown off and in distress can be more upsetting than realising they're dead. If that's completely wrong could you point me in the direction of a decent source for confirming it? thanks. And sorry for taking the whole thread off topic :D

I've heard that theory before. It goes that if you kill a soldier you remove them from the battle. If you wound a soldier, you remove three soldiers from the battle, the wounded one and the two that have to carry them off to the nearest medic. As far as I know though, no bullets have actually been designed to tumble. There was a lot of rumors regarding that about the .223, but I've never heard any reputable source make that claim.

[Lord Blackadder]

I've heard that theory before. It goes that if you kill a soldier you remove them from the battle. If you wound a soldier, you remove three soldiers from the battle, the wounded one and the two that have to carry them off to the nearest medic. As far as I know though, no bullets have actually been designed to tumble. There was a lot of rumors regarding that about the .223, but I've never heard any reputable source make that claim.

The 5.56mm wasn't designed to tumble upon hitting a target AFAIK, but it was an effect that was noticed after the round had been created. It is easy to overemphasize the importance of the tumbling and some people (even some in the military) have taken the tumbling effect as gospel and assumed that the small 5.56mm has the same effect as the larger calibers. They do not.

However, the Belgian arms manufacturer FN has designed a special 5.7mm round for use in it's P90 personal defense weapon and Five Seven Pistol. This round is of lower power than a 5.56mm rifle round but greater power than a pistol round. It is designed to be able to pierce body armor or vehicles and tumble to create a large wound channel. The jury is still out as to how well this works, but the P90 has been adopted by several US police agencies and the Secret Service has been seen carrying them. Theoretically they would be a better weapon than the HK MP5/Uzi or other 9mm SMGs because of their armor-piercing qualities.

[AppleMatt]

Wow. Bringing up guns with men is equal to pulling your trousers down and shouting "come on, who's bigger?" :D

9mm weapons are typically "stopping power" weapons, they aren't designed specifically to cause damage when they hit. Along the same lines, the idea is that they will embed into their target - if they hit bone they'll stop there. This is why anti-terrorism forces use them. The worst possible situation is entering an enclosed area with 3 x-rays and 15 hostages, shoot the x-rays only to have 2 hostages killed by bullets that went through/ricocheted off the enemies. Also it's why armed police use them, they aim to end the situation as fast as possible - save life don't end it.

Weapons of war are designed for carnage - if they hit a bone they will shatter it and destroy all the soft tissue around it (massive blood loss, massive tissue damage). If it hits soft tissue it goes right through it and hits the person behind. If it clips a bone it will ricochet out and hit someone to the side.

AppleMatt

[AppleMatt]

I know UK schools are getting more violent, but I don't think firearms are the answer just yet.

Best quote from Simpsons..."you went to a state school so I'm going to assume you have a basic knowledge of small firearms"

AppleMatt

[Lord Blackadder]

Wow. Bringing up guns with men is equal to pulling your trousers down and shouting "come on, who's bigger?" :D

9mm weapons are typically "stopping power" weapons, they aren't designed specifically to cause damage when they hit. Along the same lines, the idea is that they will embed into their target - if they hit bone they'll stop there. This is why anti-terrorism forces use them. The worst possible situation is entering an enclosed area with 3 x-rays and 15 hostages, shoot the x-rays only to have 2 hostages killed by bullets that went through/ricocheted off the enemies. Also it's why armed police use them, they aim to end the situation as fast as possible - save life don't end it.

Weapons of war are designed for carnage - if they hit a bone they will shatter it and destroy all the soft tissue around it (massive blood loss, massive tissue damage). If it hits soft tissue it goes right through it and hits the person behind. If it clips a bone it will ricochet out and hit someone to the side.

AppleMatt


I think you meant that 9mm do not over-penetrate, in which case you are correct. However, at extremely close ranges (indoor firefights) law enforcement officers have been killed or wounded by their own ricocheting 9mm rounds - hence the current use of "frangible" bullets that are made of compressed metal powder and fragment harmlessly when they strike a hardened object like a steel door or concrete wall - or bone.

The problem with 9mm and most other handgun ammo is that if the bad guys have body armor - increasingly seen these days, especially with terrorists - you might as well be throwing rocks at him. Rifle rounds that penetrate are needed. 9mm armor piercing rounds do exist but are rather exotic and not seen outside a few military special forces.

[krimson]

The problem with 9mm and most other handgun ammo is that if the bad guys have body armor - increasingly seen these days, especially with terrorists - you might as well be throwing rocks at him. Rifle rounds that penetrate are needed. 9mm armor piercing rounds do exist but are rather exotic and not seen outside a few military special forces.

im so glad i stocked up on those Ranger SXT (http://home.earthlink.net/~krimson/images/P228-Black_Talon.jpg)'s (aka "black talon") before they stopped manufacturing them.

[Lord Blackadder]

im so glad i stocked up on those Ranger SXT (http://home.earthlink.net/~krimson/images/P228-Black_Talon.jpg)'s (aka "black talon") before they stopped manufacturing them.

I like the P22x series pistols. My personal favorite has to be the .40 S&W P229.

I've found a number of websites that sell armor-piercing pistol ammo, but AFAIK it is law enforcement/military only (for new manufacture). I imagine there is plenty in the secondhand market still.

[MacAztec]

I read that book and really liked it.

One reason to use one is that since .22 rounds are really cheap you can convert your .45 down to one to practice and save money.

.22s are used because they are deadly and are untracable. the russian mob (i believe) uses them for murder, because they cannot be traced

[MacAztec]

Guns are awesome. My dad is a real collector, has some real nice guns.

Best Pistol: He has a German made "Sig Sauer". He says it is so unique because the hammer can go down in a way that you can keep a bullet in the chamber, ready to fire, but the gun is 100% completely safe.

Best Rifle: Has an M-16, long barreled. It is real nice.

Assault: He has something called an MP-85 (I believe that is it). It looks like...well, an assault weapon. It has a handle that goes down in the back, then a banana clip further up. Has Single, Burst, and Auto modes. Sweet

[krimson]

Guns are awesome. My dad is a real collector, has some real nice guns.

Best Pistol: He has a German made "Sig Sauer". He says it is so unique because the hammer can go down in a way that you can keep a bullet in the chamber, ready to fire, but the gun is 100% completely safe.

Best Rifle: Has an M-16, long barreled. It is real nice.

Assault: He has something called an MP-85 (I believe that is it). It looks like...well, an assault weapon. It has a handle that goes down in the back, then a banana clip further up. Has Single, Burst, and Auto modes. Sweet

Yay, that's 2 outta 3 for me! ;D

(Sig's have "decocking" levers, as does USP's i believe.)

[Lord Blackadder]

Yay, that's 2 outta 3 for me! ;D

(Sig's have "decocking" levers, as does USP's i believe.)


Just don't try ever using the decocking lever on a CZ-52 - you might only do it once.

[MacAztec]

Yeah I love guns. I would say the coolest gun I have (i only have 2) is a German Mauser. The WWI weapon used by the German Officers. It is so rad.

My dad gave it to me. Here is teh story on how he got it.

My dad's dad's uncle was in WWI, and he relieved the weapon from a German officer that was killed. He smuggled it back to the states, and my dad's dad ended up with it. My dad's dad moved out of the house when my dad was around 10 years old, but my dad took it from him and hid it under his bed. So that makes it, around 80 years old?

I love it because of the design. All wooden, comes out of its own shell. Look it up on google.

[Inspector Lee]

.22s are used because they are deadly and are untracable. the russian mob (i believe) uses them for murder, because they cannot be traced

No gun is untraceable. Unique imperfections in the manufacture of the barrel yield striations to the interior which will mark all bullets fired from the same gun with a series of lands and grooves. These imperfections are unique to each individual barrel (not across a make or model or factory or period of time). Provided that a recovered bullet is not beat all to hell and you have the suspected weapon, a test bullet will be fired into a soft medium (e.g. water) and retrieved. Both bullets will then be placed under a comparison microscope and manipulated to see if the lands and grooves match.

And if somebody decides to get cute and try to scar their barrel with something, one can still match the lands and grooves. It is basically a fingerprint.

Now, after saying all this, things may have changed since I went through school (10 years ago) so if this is inaccurate...

[Lord Blackadder]

Yeah I love guns. I would say the coolest gun I have (i only have 2) is a German Mauser. The WWI weapon used by the German Officers. It is so rad.

Are referring to the Mauser rifle or "Broomhandle" pistol?

I have 2 8mm Mauser (http://img.photobucket.com/albums/v439/danthearcheologist/miscguns/bltactn_1.jpg) rifles, both of which are Yugoslavian manufactured near copies of the German K98 rifle; the one on top is an M24/47 and the scoped one is an M48A. If you have an actual K98 that was brought back from WWI by a US soldier I suggest you take very good care of it, it is worth a lot of money. Russian-capture marked K98k rifles (the WWII models) are currenty going for $200 for beat up examples, an actual K98 bringback (i.e. not stamped as a captured rifle, especially if you have papers to prove its origin) from WWI would easily be worth a few times that, as long as you haven't made any permanent modifications to the weapon.

BTW, .22 is almost never used for assasinations (unless you are assasinating rodents) because the cartridge is too weak. The KGB had silenced pistols in 7.62mm or 9x18mm caliber that fired a special subsonic cartridge for assaination purposes. A silenced version of the famous Walther PPK (among other pistols) was used by a number of NATO counries for the same purposes. The KGB also had a special gun for underwater assasination that fired darts.

[MacAztec]

The broomhandle pistol. It can be converted into a rifle type thing, but by itself, it is a pistol like this...

http://www.guns.co.nz/440%20int.jpg

[krimson]

Just don't try ever using the decocking lever on a CZ-52 - you might only do it once.

Well, i dont know anyone who has a CZ, so i doubt ill ever need to decock one.. but ill keep it in mind. :)

But i was taught growing up to always point the weapon in the safest direction possible when unloading, decocking, loading, racking, etc... and of course to always treat it as if it were loaded. ;)

[Lord Blackadder]

Well, i dont know anyone who has a CZ, so i doubt ill ever need to decock one.. but ill keep it in mind. :)

But i was taught growing up to always point the weapon in the safest direction possible when unloading, decocking, loading, racking, etc... and of course to always treat it as if it were loaded. ;)

Can't go wrong that way...I always do the same, even when they're apart. ;)

[Mechcozmo]

But i was taught growing up to always point the weapon in the safest direction possible when unloading, decocking, loading, racking, etc... and of course to always treat it as if it were loaded. ;)

Best advice... that way, just in case that lever doesn't work the way it is supposed to, you don't win yourself a Darwin Award.

[LethalWolfe]

Best advice... that way, just in case that lever doesn't work the way it is supposed to, you don't win yourself a Darwin Award.

Oh, hey, funny story...

A few years ago I was talkin' w/the rent-a-cop at my work, and the subject of firearms came up. All the guys that work there are trained regularly and licensed to carry .45's on the job. But, as well all know, you can't train for stupidity. A friend of his was sitting in his car and, before he got out to start his day, chambered a round in his semi-auto .45. Well, as luck would have it, the round jammed. So he's trying to pull the action back w/one hand and tilting the gun on its side w/the other to try and make the stuck round fall out. Apparently he can't get enough leverage to pull the action back far enough so he repositions himself to get a better grip and, ta'da , problem solved, the round is chambered. The only problem is that to get leverage he pushed the gun, barrel first, into his thigh and ended up shooting himself in the leg (shattering his femur).

I can only assume that the force the action going forward caused him to grip the gun, and he had his finger on the trigger...


Lethal

[Nickygoat]

Oh, hey, funny story...

A few years ago I was talkin' w/the rent-a-cop at my work, and the subject of firearms came up. All the guys that work there are trained regularly and licensed to carry .45's on the job. But, as well all know, you can't train for stupidity. A friend of his was sitting in his car and, before he got out to start his day, chambered a round in his semi-auto .45. Well, as luck would have it, the round jammed. So he's trying to pull the action back w/one hand and tilting the gun on its side w/the other to try and make the stuck round fall out. Apparently he can't get enough leverage to pull the action back far enough so he repositions himself to get a better grip and, ta'da , problem solved, the round is chambered. The only problem is that to get leverage he pushed the gun, barrel first, into his thigh and ended up shooting himself in the leg (shattering his femur).

I can only assume that the force the action going forward caused him to grip the gun, and he had his finger on the trigger...


Lethal
In a similar vein (http://www.lewed.net/images/gross/footshoot.wmv). Don't know if anyone's seen it or even if it's real. (links to WMV)

[krimson]

It seems real, but it's hard to tell if he pulled the trigger, then racked it, or if it went off somehow.

Speaking of rent-a-cops... I was hanging out in my local shop checking out a SP89, and this old lady comes in and asks how much a revolver is worth. She pulls it out of her purse (holstered) and hands it to one of the guys. He unholsters it and looks, and says to her, about $5. She is shocked, and asks why, because he's been carrying it on duty for 20 years. Her husband purchased it from a friend, and had died recently of a heart attack. He says it's a blank gun. Just at that time, the hammer drops. She says keep it, and leaves. 2 minutes later, the cops come... everyone unholsters and walks outside.

[absolut_mac]

Hmm, it's been many decades since my last science and math classes, but I clearly remember the term velocity being used. The main reason being is that in certain situations terminal velocity is reached, and then the object is neither accelerating or decelerating - eg someone jumping out a plane - and will continue to do so until it collides with something.

I may be wrong about the exact term, so I'll have to check with my NASA aerospace friend to see what the preferred term is today.

I was wrong! :o

I finally got a chance to speak to my friend tonight and he confirmed what the other MR members had already said i.e. f=ma where f=force, m=mass and a=acceleration.

When I queried him about a situation where there isn't any acceleration, for example where terminal velocity has been reached so speed is constant and acceleration is zero, he went into a long explanation of why that didn't change the situation and that the formula would still be f=ma.

Sheesh guys, thanks for reminding me that these brain cells are getting old!

[absolut_mac]

im so glad i stocked up on those Ranger SXT (http://home.earthlink.net/~krimson/images/P228-Black_Talon.jpg)'s (aka "black talon") before they stopped manufacturing them.

Correct me if I'm wrong (heck I was wrong earlier) but I think that Black Talon's are still being manufactured, but are not available for purchase by the public. They can only be legally purchased by law enforcement agencies.

[AppleMatt]

Speaking of rent-a-cops... I was hanging out in my local shop checking out a SP89, and this old lady comes in and asks how much a revolver is worth. She pulls it out of her purse (holstered) and hands it to one of the guys. He unholsters it and looks, and says to her, about $5. She is shocked, and asks why, because he's been carrying it on duty for 20 years. Her husband purchased it from a friend, and had died recently of a heart attack. He says it's a blank gun. Just at that time, the hammer drops. She says keep it, and leaves. 2 minutes later, the cops come... everyone unholsters and walks outside.

I completely don't get this story...can someone point out what I'm missing?

AppleMatt

[takao]

I completely don't get this story...can someone point out what I'm missing?

AppleMatt

me neither..... (and what is a rent-a-cop ?)

[Mechcozmo]

me neither..... (and what is a rent-a-cop ?)


Rent-a-cops are security guards who have large egos because they are 'better than you' because of the badge, rubber stick, or sometimes a gun. It isn't a nice thing to call someone...

[krimson]

Correct me if I'm wrong (heck I was wrong earlier) but I think that Black Talon's are still being manufactured, but are not available for purchase by the public. They can only be legally purchased by law enforcement agencies.

They stopped producing that particular variety, they are being produced as a different "brand", using a copper jacket (instead of steel), and without the "black" coating. IIRC, they are labeled "Winchester Supreme SXT +P", instead of Ranger SXT +P+.

--
the story above was very random, and I apologize for any confusion. :)

[Lord Blackadder]

Rent-a-cops are funny...I know a couple and they have a very high opinion of themselves (never use the term rent-a-cop around them). Whenever the "carnies" come to town there are a number of rent-a-cops that do security, and they are always dressed up in surplus police uniforms with campaign hats like state troopers and carry batons. They generally don't carry firearms though. Reminds me of that crappy movie "Super Troopers".