# Ft lbs Of Energy ?



## Bo0YaA (Sep 29, 2008)

Ok i know what this is and I know what it means in regards to stopping power. Where I tend to get a little confused is when I look at very different rounds which produce similar if not exact ft lbs of energy. For example, I have owned a NAA 22 mag mini revolver for years. The past few months I have been considering getting my ccw permit which I felt would mean I needed to look at a new gun. I was talking to my father in law about a 380 vs my 22 mag and as it turns out they have almost exactly the same ballistics for ft lbs of energy. Now the 380 is shooting a 85 grain HP bullet at 1000fps which has 189 ft lbs at muzzle vs the 40 grain HP of the 22 mag which has a muzzle velocity of 1910 fps and 195 ft lbs at muzzle.

My question is, is more mass in a bullet better even if the smaller one is providing the same or in some cases more energy? and if so, why? is it just the bigger hole theory?

Is my 22mag as efficient as the 380 in a close quarters self defense situation.


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## Lycan (Sep 22, 2008)

Those .22 mag numbers seem a little high. Do you know what barrel length was used to get those results? NAA site has ballistics info for their guns, and none of them come close to 1900 fps. Here are their charts for the 4 .22 mags they have data for:

1 1/8'" barrel http://www.northamericanarms.com/msvel.html

1 5/8" barrel http://www.northamericanarms.com/magvel.html

Black Widow http://www.northamericanarms.com/bwmvel.html

Mini Master http://www.northamericanarms.com/mmmagvel.html

They also have a table for estimating energy using bullet weight and velocity:

http://www.northamericanarms.com/energy.html

Most of those .22 mag NAA pistols are getting closer to 800-900 fps for a 40 grain bullet, and about 57-72 ft lbs of energy.

I've got a NAA .22 mag too, but I wouldn't consider it for a primary concealed piece. It's fine as an extreme back up gun, or if you really can't conceal anything larger. Afterall, a gun is better than no gun at all. The Kel-tecs and the Ruger LCP .380 are great pocket pistols that carry well and are a lot easier to shoot IMO. I haven't carried the NAA since getting one.


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## DallanC (Jan 13, 2009)

I'd hands down take a heavier bullet over a lighter bullet at the same energy.

It takes more energy to get the heavier round to speed, and it will have much more inertia than a lighter round at impact, which means more penetration and stopping power. 

I wouldn't bet my life on a .22 mag round as a self defense weapon... sure its better than a rock but not much hehe.


-DallanC


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## Bo0YaA (Sep 29, 2008)

I guess I should have checked the NAA site for ballistics. I just went here
http://www.winchester.com/products/cata ... 1&action=1

Thanks for the info though, that actually makes more sense.


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## tap (Jun 27, 2008)

I run into this a lot with the ammo for my S&W 500. I go into sporting goods stores and start looking at all the 500 ammo. Inevitably one of the salesmen will come over and want to talk about it. They always make some comment along the lines of "I'll bet those 440 gr loads are like the wrath of god."

The funny part is that there is often a box of 350 gr ammo right there that is way more powerful in terms of ft-lbs of energy. It seems like the average person looking at (or selling) ammo looks directly at the mass of the slug and gives no thought to the strength/amount of the powder pushing that slug.


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## Bo0YaA (Sep 29, 2008)

its just like the .40 SW VS the .45 the .40 beats the .45 in almost every category yet people still use the .45 because it shoots a bigger heavier bullet.


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## Lycan (Sep 22, 2008)

Bo0YaA said:


> I guess I should have checked the NAA site for ballistics. I just went here
> http://www.winchester.com/products/cata ... 1&action=1
> 
> Thanks for the info though, that actually makes more sense.


It's easy to overlook. The ammo companies really want you to buy their stuff, so they are going to put the best stats out there they can. I am 99.9% sure that any data you read for rimfire ammo is going to be taken with a rifle. Take a look at some ballistics info for centerfire rifle loads sometime. There is usually fine print somewhere that says what they used to get that data. Remington, for example, says they use 24" barrels for all their centerfire rifle testing except for a couple exceptions.


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## jungle (May 10, 2008)

Ft=lbs of Energy is a unit of Kinetic Energy or KE. KE is calculated as follows: 1/2 mass x the square of the velocity.

KE, therefore, places a huge emphasis on velocity.

A better measure of stopping or killing power is momentum. 

Momentum = mass x velocity. Just take bullet weight in grains times the velocity and you can make a direct comparison between ammo. 

Momentum, therefore, gives equal emphasis regarding mass and velocity. This speaks to penetration, impact energy, and effeciency over distances and even hydrostatic shock if velocity component of the momentum is high. 

I m not sure where the industry became obsessed with KE, highly limited in usefulness. We should all have our charts in Momentum. 

Heck, I am surprised we are all not shooting 220 swifts with all the non-sense out there about ft-lbs. 

The 380 will have a definitive wallop and penetration way beyond the 22 mag, but you wont know that until you calulcate Momentum using the correct velocity.


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## Frisco Pete (Sep 22, 2007)

I don't have your answer, but I hope I have some general food for thought for you:

Foot/Pounds of Energy is an artificial and arbitrary means of trying to quantify expected terminal performance of a cartridge/bullet and it's ability to incapacitate the living target.
The Ft/Lbs formula is mathematically biased toward velocity as opposed to bullet weight.
Proponents of heavy slow bullets use another similar formula called "pounds/feet" that is similarly biased toward bullet weight to prove their point.
However Ft/lbs has become the more accepted or at least popular formula of the two. There are also other less popular formulas such as Momentum mentioned above. All have their plusses and minuses.

However no formula I've seen takes into account a tremendous amount of variables that actually occur when a bullet strikes actual flesh and bone. For example it does not take into account any variation in bullet design - it assigns the same killing power to both hollow point and FMJ roundnose pistol bullets, although we have come to realize that the expansion of the bullet and the resultant wound cavity (both temporarily and permanent) has a terrific effect on its terminal performance. Neither does it assign any value to frontal area. So in an oft-cited example the ft/lb performance of a hyper-speed 50-gr .220 Swift can be better than that of the slow, heavy .45-70 - even though we would much likely have a series of solid kills with the 400 grain .45-70 on elk.

Another factor that neither formula takes into account is bullet penetration and wound cavity depth. We all know that a bullet needs to penetrate to the vitals to disrupt the systolic system and cause rapid blood loss and a fatal drop in blood pressure, or massive disruption of the nervous system to effect a kill. Bullet construction has a major part to play in whether the bullet will penetrate the vitals. For example a light 100 grain 9mm HP bullet fares much poorer in reaching the vitals (but gives a large, but shallow wound cavity) than does a heavy or slightly delayed expanding bullet like the Speer 124-gr Gold Dot or even heavier bullets like the 180-gr .40s or 230-gr .45 Auto with their deeper wound cavity. More velocity actually can make the bullet expand faster and because it opens like a parachute in the body, penetration can be limited because of this. This is certainly a balance that comes into play when bullets are designed by the ammo maker. This factor definitely can come into play when using a light, fast bullet like the .22 Mag that is intended to open up well on varmints from a rifle. Use in a pistol may actually aid penetration because velocity (and ft/lbs as well) are down.

Anyone with hunting experience or that has had to use a weapon for self-defense knows that bullet placement is of paramount importance and that no matter how many ft./lbs of energy you dump in the wrong place it won't achieve the desired result.
Ft/lbs will make a steel gong swing harder/further because the target is solid and absorbs all the energy if stoutly constructed enough. But animals are soft tissue and don't give those ft/lbs much resistance to work against - so "knock-down" power formulas must all remain suspect. They just aren't nearly as scientific as they sound. But we all love science, wherein lies the quandry...

So personally, while like everyone else, I tended to take ft/lbs and all the other formulas quite seriously when I first got into all this gun and ballistic stuff - nowadays I really take it all with a huge grain of salt. I don't think they mirror the real world accurately enough to be taken as exact gospel or more than a real general guide. We know that velocity helps and that bullet weight helps, and that small bullets can make big fatal holes at times, but I think formulas to quantify this are grasping at straws. "Slide-rule" approach can get us in trouble because it is derived from theory. The performance of most all calibers, either for self-defense or for hunting is a matter of record. We tend to know what works. For example, no one will argue that both the .45 Auto in pistols or the .30-06 in rifles works, and has worked for around a century. What works - works. It is a matter of record. And not all calibers will work all the time either. Normally good calibers can fail on occasion and "weak" calibers can work like a champ at times. Nothing works all the time, nor none of the time. What we want is something that has a history of working well most of the time, or at least fails less often, and as mentioned - and that is normally a matter of record.

All rifles and pistols are capable of inflicting a lethal wound (sooner or later) including those chambered for a .22 rimfire of one sort or another including the .22 WMR, so their inherent lethality is not the question. Though lethality gets so much emphasis, with formulas like ft/lbs, leading the discussion, in the _real_ world we want more than just lethality because the most important requirement of a self-defense arm is to either stop one's opponent from further aggressive activities with a minimum of shots fired (preferably one); or for hunters to drop game fast and cleanly - basically the same general idea.
We can _kill_ people (or game) with any number of weapons and calibers, but to _stop_ an opponent from harming us is an entirely different matter.
Of course another CCW truism is that _any_ gun or caliber we have on our person is better than a superior caliber or gun left at home!

So I hope that this gives you some general food for thought when it comes to selecting your self-defense caliber and helps you realize that you will have to do more research on effectiveness than simply rely on some theoretical formula like "foot/pounds" etc.


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## Bo0YaA (Sep 29, 2008)

Great post, thanks for taking the time to further enlighten me about this. I appreciate it


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## longbow (Mar 31, 2009)

Good post Frisco Pete. I see it the same way.


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## MEEN (Jan 27, 2009)

Frisco Pete said:


> So I hope that this gives you some general food for thought when it comes to selecting your self-defense caliber and helps you realize that you will have to do more research on effectiveness than simply rely on some theoretical formula like "foot/pounds" etc.


Not a bad post frisco but it is kind of fundamentally flawed... On a nit picky level energy is ft-lbs and the "pounds/feet" formula you referred to is work and its units are lb-ft (sorry I am a Mechanical Engineer I can't help it) which is all energy and the same thing (basically). I agree with finding out the effectiveness but it's kind of like saying shoot what works. Well how do you make that decision without having to purchase rounds and try it.... You figure it out from Kinetic Energy, plus its a good seller cause most people don't understand it and bigger is better right? I can promise that the engineers that designed the bullet know how it is going to react from the time it leaves the muzzle to the time it exits the target. *If anyone was wondering the integral of momentum IS kinetic energy so it's kind of vague to analyze the comparison. I wont get into what implications that has but it's like comparing velocity and acceleration. They are dependant upon each other. So it's absolutely wrong to say that comparing Momentum is better.* Let's just say that comparing momentum is an easier way of understanding what is happening BEFORE it reaches the target.

Basically I would look at what is important, and that is the amount of energy transferred from the bullet in flight to your target. Energy and Momentum are CONSERVED. Just because something has a large amount of momentum doesn't mean your target will feel all or even 10% of that momentum (unless the bullet doesn't pass through). I could go into some long spill about bullets passing through or not and yadda yadda yadda. It's boring. A larger bullet (after expansion) is able to transfer more of its energy into its target. Thats why bullets are made to expand. A smaller bullet will need more ft-lbs of energy in order to transfer the same amount of energy as a larger bullet.

I feel like I just answered nothing with a little of everything and said the same as Frisco in a different way. Truth is the consumer doesn't really know the effectiveness of the load because they have no idea how to figure out how much of the momentum/KE will be transferred to the target.

Just get the load with the larger KE. More than half of the time it will impart more momentum/KE on your target because it has more momentum/KE itself.


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## Artoxx (Nov 12, 2008)

Someone, I think it was Sherrif Jim Wilson, was once asked why he chose to carry a .45. His response was,"Because they don't make a .46."
That response taken from a man who used a gun every day of his life, and on MANY occasions to actually SAVE his life and the life of others, leads one to ask why?

The basic reason he gave was that in his personal experience, the biggest hunk of lead he can throw downrange at the bad guy, the more likely the bad guy was to quit being dangerous.

I think it was also the same person who said that the BEST gun to have in a gun fight, was whichever one you had in your hand. He clarified this by saying, if you won't carry a gun EVERYWHERE and all the time, then the ONE time you are guaranteed to need it, will be one of the times you have left it home.

Get the biggest, most powerful gun that YOU WILL CARRY, because it doesn't matter a rats whisker how big or small your gun is, or what caliber, grain weight, or FT. pounds of energy it may produce. If it isn't where you can get to it when you need it, then it is not worth ANYTHING.
A .22 mag, a .25 auto, a .32 acp, or anything else on the LOW end of the scale is NOT the gun you should choose first. BUT if it is the only gun you have, then by default it is the best gun for you to use.
Bigger is not always better, and that definitely applies to the size of the gun. If it is too big for you to carry EVERY day, EVERYWHERE, then it is too big.
However, the biggest gun that you WILL carry everywhere and anywhere, IS the best gun for you.

YOU are the one who will have to make the decision on what, when, why, how, and especially IF. Make the best decision that you can.
It is all well and good to discuss ballistics in all it's forms and patterns, but what it comes down to is WHERE is the gun going to be if you need it. Looking powerful and immpressive in the safe at home? Or being available out in the world when your life depends on it.
Once you find a gun that fits you and your lifestyle, THEN worry about what calibers it is available in, and get the biggest. 

Some of this is tainted by MY opinions, but most if not all of my opinions were developed by reading, researching, and actually talking to people who had both been there and done that.
I have had 3 carry weapons. 
1. Glock 21, FULL size .45 caliber. 13 rounds in the mag and one in the pipe.
2. Colt Officers model Compact .45, 6 rounds in the mag, and one in the pipe.
3. LLama Compact .45 7 rounds in the mag, one in the pipe.
Sadly I am not currently carry enabled, either in permit OR firearm and the only handgun I have is a .44 mag Ruger with a 10.5" barrel.
Not ideal for concealment purposes. :twisted:
Though with the new regs saying that it is legal to carry a loaded gun in the vehicle without a CCW, it will be getting a lot more time out of the safe.
Just as soon as I verify what those new regs actually say, instead of relying on hearsay form people who may not have it quite right. :wink:


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## cowmilker (Dec 17, 2008)

I have heard say that ".22 mag is considered a good round for warfare" because a soldier hit with one will remove 1-2 others from a fight as they are trying to save him. But at 2:30 am in a dark ally downtown, there are not any other soldiers to worry about. You are generally only going to have 1-2 attackers. 
When I was in the police academy 9yrs ago. One of the range masters told us (I think it was in reponse to a caliber question) "all these side arms are for is to get heads down while you are backtracking to your patrol car to get the longarm you should have had in the first place". (Then they taught us to shoot center mass, two tothe the body one to the head ect.) Therefor I bought a 9mm with 19rnd mags, but I am not in police work anymore, and I don't carry a shotgun in my car very often, so I MAY be re-evaluating my carry choice in the future to try to get some thing that comes a LITTLE CLOSER to having some stopping power (the point is that NO HANDGUN has stopping power). One great article (I think) is from Evan Marshall called "selecting the duty weapon-is caliber the key", it would be a good article to read (google it). I think in MOST (the qualifying word) situations you would not be sorry you had a .380 when the confrontation was over. You may be sorry with a .22 mag.


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## James (Oct 7, 2007)

> 1910 fps


As already noted the 1910 fps is most likely in a rifle barrel, where the 380 data was most likely in a semi-auto pistol with a 3 or 4 inch barrel. If you shoot the 22 in a short barrel you lose quite a bit of velocity so now the 380 has the edge on energy. It is also a bigger heavier bullet. I would certainly pick the 380 over the 22 if I had to choose.

One other factor that is often mentioned when this question comes up is that center fire ammo is usually more dependable than rimfire ammo to fire every time.


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