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Foot pounds energy in Air Rifle

03/23/2008 2:41 PM

My Brother sometimes* uses an Air Rifle for shooting pigeons (V tasty breast meat fried with garlic & red wine).
The maximum allowable 'power' for one in the UK is 12ft lbs.
Now this strikes me as barmy as.
a) It's not an SI unit.
b) Surely ft lbs isn't a measure of power as it's units are just length and mass? foot pounds weight or foot poundals maybe ...
Am I..
a) Just wrong and slightly deranged..
b) Technically correct but a pedantic git, as everyone says 'pounds' when they really mean 'pounds weight'.
c) Irresistible to women. Bored 'cos it it's a cold bank holiday Sunday.

Del

* When it's not Sunday morning or he's away from habitation he uses his restored underlever 12bore circa 1870

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#1

Re: Foot pounds energy in Air Rifle

03/23/2008 2:49 PM

Normally, in ballistics, you would use the muzzle energy. 12 ft-lb sounds a little high for a Red Ryder BB gun. It's only important to have enough that "You could put your eye out!".

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#2
In reply to #1

Re: Foot pounds energy in Air Rifle

03/23/2008 2:57 PM

Ah...I didn't make it clear... I know the figure is correct.. it's just the units that strike me as odd.

just to stir any potential controversy he chose a .177 over the .22 on the grounds that at the same energy the .177 would have a higher velocity and hence flatter trajectory...
I'm sure he's had a few arguments in the pub over this choice .

Del

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#3
In reply to #2

Re: Foot pounds energy in Air Rifle

03/23/2008 3:26 PM

Oh surely (and yes, I will call you surely) you're not gonna bring up that poundal vs slug thing again, are you? You guys convinced us to go with feet, pounds, and guineas instead of the French meter and Newtons; then you abandoned us.

The velocity vs mass argument is timeless and probably not ever to be settled. I always used a 12 gauge, #7 shot for pigeons.

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#65
In reply to #3

Re: Foot pounds energy in Air Rifle

10/01/2009 8:19 AM

then you abandoned us

In my history lessons it seemed that we didn't leave voluntarily, but were forcibly ejected*. You were hardly "abandoned"...

*Them Frenchies had a hand in that too...

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#28
In reply to #2

Re: Foot pounds energy in Air Rifle

03/24/2008 1:03 PM

Del, you always have to remember that when we talk in feet, pounds, and BTUs that your pound unit is a fraction of a Euro, which tends to complicate things. So, if we use foot - Euros, does that help? It helps us to include the value of the weapon in our calculations. The value foot-Euros can be converted to pound - pounds for simplicity.

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#4

Re: Foot pounds energy in Air Rifle

03/23/2008 3:30 PM

Well, of course the American has to come in for the rescue...

Ft-lbs is not length times mass, it is length times force.. In this case lbs force not lbs mass, and indeed in our beautiful system of units which we of course refer to as "customary" the lb is most often used for force as slugs are more typical mass units (as well as being slimy creatures that are essentially snails that somehow lost their shells).

Bottom line is that ft-lbs is the customary unit for torque, which can be related to power.

Further proof that the UK has not completely given in to SI, and that America is not the last bastion of "customary" units

(although I am not endorsing ft-lbs as a good unit for energy of an air rifle, that is just barmy.)

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#5

Re: Foot pounds energy in Air Rifle

03/23/2008 6:10 PM

So where does it get the foot and where does it get the lbs value from if we talk about a riffle?

I am just very confused about this. I always fight with the keepers of the imperial bastion about how incredibly daft it is to hold on to something derived from the anatomical measurements from one of your ancient kings but I do know most of the ways it works in ( that I need for work or hobby) and this one seems a bit off the mark so to speak.

Please elaborate and maybe after that we can discuss the various ways to cook pigeon breast although I would have thought you a proper cat and eat it "au naturel".

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#6
In reply to #5

Re: Foot pounds energy in Air Rifle

03/23/2008 6:50 PM

In terms of testing air rifles I think they just calculate it from muzzle velocity and projectile mass.

I was amazed that something enshrined in legislation could be in other than SI units.

I wonder what the force in an arrow from my longbow is???

I often get a nice bag of pigeon breasts when I see my Bro' but not this time.

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#10
In reply to #6

Re: Foot pounds energy in Air Rifle

03/24/2008 4:40 AM

It seems if I wanna get more breasts...I just have to increase the force in my muzzle don't I?

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#27
In reply to #10

Re: Foot pounds energy in Air Rifle

03/24/2008 11:44 AM

I would tend to agree. Just don't forget to advertise.

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#45
In reply to #6

Re: Foot pounds energy in Air Rifle

03/25/2008 11:30 AM

That is a normal (if old fashioned) description for energy, I also believe that the .177 pellet will travel faster and is effectiver at longer ranges than a .22, I used to use both....

I even used to use a Crossbow (and tuned up air rifles) for Pheasants/Partridges etc in our UK garden and I used Fiberglass bolts with the metal tips removed (otherwise they might have gone too far for safety if I had missed!!!). My neighbor used a shot gun!!! Luckily our hedge was very thick!!

The 12 Ft/Lbs can be expressed in Joules of course, which would be about 16.26981 Joules.

A good page for conversions of various types is at the following:-

Conversion Formulars

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#7

Re: Foot pounds energy in Air Rifle

03/23/2008 11:17 PM

You guys got it right. It's muzzle velocity in feet per second times the projectile weight in pounds. And, yes, I would also choose the .177 over the .22 given the 12 ft/lb limitation.

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#9
In reply to #7

Re: Foot pounds energy in Air Rifle

03/24/2008 12:45 AM

It's muzzle velocity in feet per second times the projectile weight in pounds.

Sort of.

E=1/2 MV2. So the muzzle velocity is squared. In other words, a 800 fps muzzle velocity would represent 4 times the energy of a 400 fps muzzle velocity, given the same projectile mass.

In this case, mass vs weight matters. An 8 grain projectile going 800 fps would work out like this (using 32fps2 for g):

E = 1/2 x (8/7000/32) x 8002

E = 1/2 x (.0000357) x 640,000

E = 1/2 x 22.848

E = 11.424 ft-lb

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#8

Re: Foot pounds energy in Air Rifle

03/24/2008 12:09 AM

Nothing can argue with my 12 guage. I have many weapons. 30/30, 30'06, .22, My uncle left me a 1932 over/under 12 guage Savage, made right next door, in Springfield, Massachusetts. I use it all the time, but just for clay pigeons now.

I thought all Bank holiday's where on a Monday?

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#22
In reply to #8

Re: Foot pounds energy in Air Rifle

03/24/2008 9:43 AM

Hey Bricktop, I have a Savage over/under as well. Mine is a .223 and a 20 gauge. It's a decent deer/turkey combo gun.

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#23
In reply to #22

Re: Foot pounds energy in Air Rifle

03/24/2008 10:00 AM

Oh, that must be a sweet unit. How old is it? Where did you get it? I don't think they make them anymore, at least not in this country. Do you want to sell it? I have money!

Mine is a 12 guage, full choke on the top, modified on the bottom. It's not for sale.

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#25
In reply to #23

Re: Foot pounds energy in Air Rifle

03/24/2008 10:51 AM

Honestly not sure on the age. I'll have to check that out later (<--at that place known as... work). I don't have any plans of selling her, she is just too interesting and in great condition. I honestly don't use it all that often, but it makes for good conversation. Most people have seen over/under shotguns, like the nice Berreta trap guns, but not a rifle/shotgun combo. I have a Remington 1100 12 gauge shotgun that sees more use (trap, skeet, sporting clays).

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#11

Re: Foot pounds energy in Air Rifle

03/24/2008 5:35 AM

20 ft lb is amount of energy needed to raise a 1 lb weight 20 ft (or a 20 lb weight 1 foot) etc. Power is energy per unit time.

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#13
In reply to #11

Re: Foot pounds energy in Air Rifle

03/24/2008 7:00 AM

Whoops ..yes I was sloppy too I meant energy not power....

No one seems keen to answer the question...
Basically is 'pound' a measure of mass or force...? I believe technically it's mass, and 'pound weight' or 'poundal' is force.

But WTH I got energy .. power wwrong...maybe I should just curl up and have a nap.

Del

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#14
In reply to #13

Re: Foot pounds energy in Air Rifle

03/24/2008 7:41 AM

"No one seems keen to answer the question...
Basically is 'pound' a measure of mass or force...? I believe technically it's mass, and 'pound weight' or 'poundal' is force."

I did! It is a measure of force!

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#17
In reply to #14

Re: Foot pounds energy in Air Rifle

03/24/2008 8:25 AM

Yes you were right but is the unit as lbs or lb not wrong then?

I think it should have been lbf, which is pound force.

Lb or lbs is pounds in weight so as it is used on torque wrenches too old to do the Nm stuff.

If Del is allowed to be pedantic I think we should follow suit and make him feel at home

All these imperial measures are ridiculous anyway. Who wants to know a length compared to the king's forearm or his thumb width? What about weighing yourself in stones and pebbles, absolutely stupid. The biggest problem is that it is not easily converted by decimal point positioning either. Nobody in their right mind would say he just walked 13 KiloYards or even a 10th of a mile.

Ok I will go and hide now! Del, have you got any room on your cosy cushion for me for a few days, I expect them to be after me now.

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#19
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Re: Foot pounds energy in Air Rifle

03/24/2008 9:00 AM

Yeh.. but am I going to believe a bloke playing a guitar ?

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#15
In reply to #13

Re: Foot pounds energy in Air Rifle

03/24/2008 8:01 AM

Why are you asking us? We wanted to go with mass in beads, distance in moccasin length, and time in moons, but no, you guys had to send General Gage over here to whip us into shape. To this very day I have trouble converting shillings into beaver pelts.

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#24
In reply to #13

Re: Foot pounds energy in Air Rifle

03/24/2008 10:41 AM

No one seems keen to answer the question...
Basically is 'pound' a measure of mass or force...?

Actually, I thought I already answered that... although I guess by way of example, rather than directly.

A pound is a measure of force. The corresponding measure of mass is a slug. The "slug" was developed in a vain attempt to have a logically coherent system of units with parallels to those in what we use to call the metric system.

I think either Isaac Newton or Stephen Hawking said the following, or else I just made it up:

  • A little background: lbf, lbm, slugs, pounds, poundals, lb-ft and foot-pounds are units of a fundamentally totally fricked-up system. Calculations that are simple in the SI world become confusing in English units because the system is so friggin, unbelievably, irreconcilably screwed up. People who use poundals, lbf and lbm are moronic nitwits who should be ground up and flushed down a toilet. Ditto for people who use kgf (to mean the force of one kilogram).

Work = energy. Thus, one foot-pound of energy can do one foot-pound's worth of work. In this usage, pound MUST be a unit of force: work is a force applied over a distance. When one says I weigh 170 lbs, he is saying I exert a force of 170 lbs against the floor. Therefore, he is indirectly saying "I have a mass of 5.3125 slugs". (That mass, times the acceleration due to gravity, 32fps2, equals the force 170lb). (In real units: That mass [77.53kg] times the acceleration due to gravity, 9.8 mps2, equals the force, 759.7 Newtons.)

If energy is measured in foot pounds, (distance x force) then for force we could substitute MA, (because F=MA). So energy would be distance x mass x distance / time / time. If you keep track of the units, they all cancel out in the right way, so you can go from E=1/2 MV2 to E = F x D

Using slugs for mass and pounds for force works well, and is essential, I think, for avoiding confusion. The other units, like poundal, lbm and lbf just add confusion. There are those who use kgm and kgf which I think is completely screwed up.

Of course, the average American and Brit will say I weigh 170 lb (which is correct from a physics perspective). The average European will say "I am having a weight, yes? you see, of how you say, to be 77 keeelogrrrahm, oui?" The European should be saying "I have a mass of 77 kg" or "I weigh 759 newtons."

Of course, do as I say, not as I do. I use mixed units and the incorrect units all the time, because I'm a lazy SOB. Also, I almost never actually put all the units in calculations, and properly cancel them out. I use the google calculator as punishment when I am confused... it will happily and correctly accept mixed units, but will not give you the expected answer if you are too lazy.

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#26
In reply to #24

Re: Foot pounds energy in Air Rifle

03/24/2008 10:59 AM

Ok I come clean before I even start here, I contemplated posting this reply as a guest as it is very embarrassing ok.

First time I ever used a torque wrench, it was one of those long ones with a bendy bit and a needle on a scale at the handle thing, I was torquing up my valve rocker blocks of my beemer boxer. I had done the head conversion to a lead free type and with better fitting over sized pistons (old bike so worn a bit). I misread the scale and used the wrong scale which resulted in grotesquely over tightened rocker blocks.

First start was fine and absolutely no problem for the 20 odd miles I did with it but then I stopped and had a cup of coffee at my mates house. An hour or so later i was going to go back home but the bike would not start. My mate helps to push start the thing and after some time it did go but it had a afterburner flame of about 2 meters out of one pipe and my mates trousers were black. The bike seemed to run on 1.5 cylinder so I limped home on it. When I took it apart, the rocker blocks of the left side cylinder where literally flattened by the torque and I had to replace rocker blocks, rocker shaft and the cylinder studs as well as heli-coil one stud thread in the engine block. Small mistake big consequences. Think twice and do once is now my motto.

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#31
In reply to #24

Re: Foot pounds energy in Air Rifle

03/24/2008 5:39 PM

OK, but that still doesn't answer the question of how many gills of water there are in a pound?!? But other than that, I broke down and gave you a GA vote (actually to both of your answers...). Now, as to those gills...

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#12

Re: Foot pounds energy in Air Rifle

03/24/2008 6:47 AM

So the unit is wrong! Somewhere along the lines of the calculation the seconds have been lost.

Unless the pounds you mention is actually lbf which is the exerted energy unit from long ago. You are right Dell, it should have been updated to Newtons.

This is why we have the industrial standards, so there will not be any confusion over it.

I think you will find many of these little "gems". They still say psi don't they?

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#16

Re: Foot pounds energy in Air Rifle

03/24/2008 8:16 AM

According to Ian V Hogg (Ex Master Gunner British Army) Story Of the Gun, they were aware that this is combining different units so "For Imperial measurement, with the bullet weight in grains and the velocity in feet per second, multiply the weight by the velocity squared and divide the product by 450,437. The result is in foot pounds.

For metric with bullet in grams and velocity in meters per second, weight times velocity squared divided by 2007 gives you Joules and Joules X 0.74 gives foot pounds."

This raises two new questions, were all gunners mindblowingly brilliant mental arithmetic freaks casually dividing everything by 450,347 at the drop of a hat. and secondly on the whole metric issue, if metric is so damn good why do the french still sell wine by the dozen.

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#46
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Re: Foot pounds energy in Air Rifle

03/25/2008 12:06 PM

"...two new questions..."

Answer #1 is somewhat guesswork, but I suspect the gunners were less savantes terrible and more than average bored stiff, with little to do between cannonades but create tables and charts so they could look it up in an instant.

Answer #2 is the French douzen is a tradition - the French vehemently oppose any changes to the language, including retiring any archaeic words, so expect it to be with us for a looooong while.

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#18

Re: Foot pounds energy in Air Rifle

03/24/2008 8:57 AM

They taught us way back in Basic Engineering that the work done on an object was equal to the change in kinetic energy which would be seen by that object... There is also the impulse - momentum relationship. As I remember (it was over 30 years ago) there was a derivation of both relationships.

So if you integrate the area of the bore times the length (to get force) times the length you get ft lbf as the work done on the projectile which will equal its change in KE.

.177 vs .22 177 does give higher velocity and I seem to get better penetration at short ranges anyway. At long ranges the .22 seems to retain more velocity and performs somewhat better...

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#20

Re: Foot pounds energy in Air Rifle

03/24/2008 9:10 AM

I'm not sure I've ever seen an air rifle specced in therms of ft-lbs, here in the US they usually only give the muzzle velocity in feet per second (FPS). If the above calculations are correct, 800 FPS to keep you under 12ft lbs sounds weak. I had one as a kid that was around 1400 FPS and we (my childhood friends and I) used to run around the woods shooting each other.

I hope the UK pigeons are better then the US ones....they're the rats of the sky here...

Avery Montembeault

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#21
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Re: Foot pounds energy in Air Rifle

03/24/2008 9:23 AM

These are nice fat countryside wood pidgeons that feed on the farmer's fields eating the young crops at this time of year...hence my Brother has no problem finding shooting.
Very tasty, he just takes off the breast meat, he sells some to a local butcher who makes 'em into sausages...It pays for his shotgun shells, nice to have a hoby that pays for itself.... there are guys who pay a fortune for some shooting.

Del

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#32
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Re: Foot pounds energy in Air Rifle

03/24/2008 5:51 PM

Here in the US, we'd call them 'doves'. We use 'pigeon' for the Asian rock dove. And I concur, a nice squab on toast is a delicacy one need not be a cat to appreciate. Never heard of dove sausage, but I guess it'd be a bit like chicken sausage... Odd what you Brits won't turn into bangers - even more so than the wurst in Germany.

That 800 fps muzzle velocity is lame - last air gun I had was a Sheridan pump model. 10 pumps would give you ~1,750 fps, and at 50 feet, it would bend a dime nearly in half. Oh, sorry, don't know what the comparable coin would be in the UK - sprechen sie 'dime'?

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#30
In reply to #20

Re: Foot pounds energy in Air Rifle

03/24/2008 1:37 PM

The old Daisy guns were specced at about 5 ft-lb. They probably were worried about shooting Little Beaver's eye out. When the multiple pump guns became popular (sometime in the 1950s), they went a lot higher.

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#29

Re: Foot pounds energy in Air Rifle

03/24/2008 1:07 PM

Not relevant at all, but I just looked up some energy figures for longbows....

33ft-lb would seem to be about what I'd get from my longbow...
So if you get the choice of being shot by an air rifle or a longbow... chose the air rifle .

Del

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#33
In reply to #29

Re: Foot pounds energy in Air Rifle

03/24/2008 5:53 PM

What would that convert to in 'muzzle' velocity, any idea?

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#35
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Re: Foot pounds energy in Air Rifle

03/24/2008 6:04 PM

Damn..I'll have to get my books out again...

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#36
In reply to #33

Re: Foot pounds energy in Air Rifle

03/24/2008 6:06 PM

About 180ft/sec for a target arrow....

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#38
In reply to #36

Re: Foot pounds energy in Air Rifle

03/25/2008 7:22 AM

Fast enough I doubt you'd see it coming. So much for the beat-'em-up movies where the Ninja warrior dodges the archers' arrows, eh?

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#41
In reply to #38

Re: Foot pounds energy in Air Rifle

03/25/2008 9:49 AM

Yeh..I used to piss myself at that Kung Fu series where the guy knocked arrows out of the way...they were soooo obviously thrown by the camera man.
I've stood at the bad end of a rifle range when a bolt was shot from my repro 'light hunting crossbow' (275lb draw weight).... it sounded like a steam train coming for a split second then was this almightly thud .

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#34

Re: Foot pounds energy in Air Rifle

03/24/2008 6:02 PM

12 foot pounds .....

Is that how many times you'll jump after you get shot? Or stomp your feet 12 time?

I remember the max energy in J when I was back in HK. Don't remember the number but I know the .38 the cop use is just above the limit.

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#37

Re: Foot pounds energy in Air Rifle

03/25/2008 6:37 AM

Hello Del

a) Presumably it's in UK, so yes you would expect it to be in joule, 16.27 joule since you ask.

b) you're right, it's a measure of energy. Should really be ft.lbf (lb force). But not poundals. Poundal is force to accelerate 1 lb mass at 1 ft/s2, and = 1/32 lbf (taking g = 32 ft/s2), but you don't hear much about it these days. Other approach is to keep the lbf as force unit and define a mass, the slug (= 32lb), such that 1 lbf accelerates 1 slug at 1 ft/s2. As we try to be metric in UK, we don't hear much of that either, I don't know whether they use it over the pond, or just use lb mass and lbf and put g in formulas to get the right result.

I suppose 12 ft.lbf is the energy in the pellet (as opposed to in the compressed air)? If so, and taking 1 gram for pellet mass, it comes to 180 m/s or 400 mph, which seems about right.

Cheers.....Codey

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#44
In reply to #37

Re: Foot pounds energy in Air Rifle

03/25/2008 10:30 AM

I don't know whether they use it over the pond,

Yes, we slug people around often. Only a few countries can outdo us in violence.

I use slugs all the time in aerodynamics and hydrodynamics. By doing so, the various formulas "make sense": if you want SI units you can just swap them in. Lbf and lbm is just too weird for me. Even weirder, in my view, is kgm and kgf. When you already have clearly defined units that are in common usage why throw a spanner (wrench here) in the works?

I suppose 12 ft.lbf is the energy in the pellet...

Let's see... I know the formula for that: E=MC2. Don't get near me with that pellet!

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#62
In reply to #37

Re: Foot pounds energy in Air Rifle

04/21/2008 1:33 PM

Found this:-

http://www.airguns-online.co.uk/you_and_the_law.htm

UK Legal Limit

To calculate the power of an airgun you need to use a chronograph to measure the speed of the pellet (in feet per second) when fired, and you need to know the weight of the pellet in grains. Once you have that information you perform the following calculation: - speed (ft/sec) X speed (ft/sec) X weight (grains) 450240
this gives you the result in foot pounds force (ft-lb).
As mentioned the legal maximum for an unlicensed air rifle is 12 ft-lb which from changing round the above formula, gives the approximate values as follows:-
A .22 pellet weighing 14.4 grains, maximum permissible speed is 612 ft/sec
A .177 pellet weighing 7.9 grains, maximum permissible speed is 826 ft/sec
The corresponding figures for a pistol are 433 ft/sec for a .22 and 584 ft/sec for a .177
The pellet weights used in the above calculation are typical weights for the sizes of pellet but you must always check the actual weight of your pellet before performing your own calculation.

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#63
In reply to #62

Re: Foot pounds energy in Air Rifle

04/21/2008 1:51 PM

WOW! Pretty sophisticated for the above average user. Even more so for the average Joe.

Isn't this something that would typically be done by the manufacturer?

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#39

Re: Foot pounds energy in Air Rifle

03/25/2008 7:29 AM

Never did answer your original question(s) - multiple choice, I pick both a) and b), c) is a non-starter, Easter Sunday shouldn't be a bank holiday...and you rightly lined out the remainder.

By way of expalanation, a) is correct because you are clearly at least slightly deranged; b) is also correct because you have demonstrated the ability to be a pedantic git.

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#40

Re: Foot pounds energy in Air Rifle

03/25/2008 8:08 AM

What you need to get for your brother, possibly for Guy Fawkes day, is an old Chesapeake Bay goose gun. They were 8 gauge shotguns, with barrels roughly 6 feet long and trunnion mounted (unless you had a really strong, really stupid brother-in-law to hold it), and were loaded with BB shot.

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#42
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Re: Foot pounds energy in Air Rifle

03/25/2008 9:56 AM

That might be just a tad difficult to come up with, but eBay has a Chesapeake Bay antique goose call on sale for under (so far) $7.00US. Here's a pic from about 5 minutes ago...

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#43
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Re: Foot pounds energy in Air Rifle

03/25/2008 10:01 AM

He has restored 4 bore punt guns and has an amusing anecdote ... 'The indoor punt gunner'
I expect you can figure it out yourself...but in involves a hole being blown in a wall .

Del

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#47
In reply to #43

Re: Foot pounds energy in Air Rifle

03/25/2008 12:18 PM

OK, I'll bite - what is/are "4 bore punt guns"? It sounds like a four-barrelled boat-mounted fowling piece, but etymology seldom if ever works that way...is it more like this:

???

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#48
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Re: Foot pounds energy in Air Rifle

03/25/2008 1:58 PM

It's a single barelled boat mounted fowling piece. 4 bore... is a big bore... 4 balls of that bore would weigh a pound...same way that a 12 bore is so called because 12 balls of that bore would weigh a pound.

Del

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#49
In reply to #48

Re: Foot pounds energy in Air Rifle

03/25/2008 5:41 PM

QUARTER POUND CANNON BALLS?!? What kind of "fowl" do y'hunt with something like that? Seems extreme even for ostriches or emus. Moas? Elephant birds? But they went extinct pre-gunpowder... I'd pick it for big game in Africa, maybe, but crikey!

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#50
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Re: Foot pounds energy in Air Rifle

03/25/2008 6:09 PM

QUARTER POUND CANNON BALLS...

No it fires shot!...the ball thing is just how the bore (gauge or is it gage? to you folk over the pond) was measured in days or yore..

Del

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#51
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Re: Foot pounds energy in Air Rifle

03/25/2008 6:27 PM

Here it is gauge - nowadays, a 12-gauge (12 ga abbreviated) is about as big as you can normally find, and is used for ducks and geese. Or with slug loads, deer and elk.

How MUCH shot, and of what size? To me, the thing sounds like an artillery piece, not a hunting gun! And if it's four balls to the pound, how do you fit them in the barrel to figure the "bore"? Side-by-side seems way huge, but end-for-end wouldn't be so much over-sized. In which case, why have four? I still think this is the smooth bore version of the express rifle b'wana used to use on these guys...

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#52
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Re: Foot pounds energy in Air Rifle

03/25/2008 6:52 PM

You're all looking at the technicalities from the wrong end. All shooting problems derive from shooter's thrombosis, which roughly translated means the clot holding the gun.

Simon

ex dogshit expert Shooting Times.

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#53
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Re: Foot pounds energy in Air Rifle

03/26/2008 3:39 AM

I think this is the actual gun my Brother restored.. I know he sold it at auction and it looks like the one...he had to re-engrave the underlever and a fair bit on the lock. . He did a nice tudor rose where your thumb works the underlever. I remember saying he only had 4 or 5 cartridges for it as thay are hand made of brass and are re-loaded...you won't find 4 bore shells over the counter!

Del

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#56
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Re: Foot pounds energy in Air Rifle

03/26/2008 7:26 AM

"...you won't find 4 bore shells over the counter!"

I wouldn't wonder - did some research. Those things were outlawed (albeit still used, I'm sure) in the US just before WWI. Game conservation laws made market hunting illegal, and who would need something said to be able to kill 100 birds per shot just to feed the family? You can still buy the shells at auction or (as seen here) on eBay:

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#60
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Re: Foot pounds energy in Air Rifle

03/31/2008 12:25 PM

Del...heeere kitty kitty. Look at what I found today while looking for something else...

http://www.youtube.com/watch?v=ltQeCrVJtLU

You're gonna LIKE this I bet...

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#61
In reply to #60

Re: Foot pounds energy in Air Rifle

04/03/2008 7:59 PM

So that is how they killed off the passenger pigeons! Maybe I can get one for the blackbirds that are dominating my bird feeders and giving me dirty looks.

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#55
In reply to #49

Re: Foot pounds energy in Air Rifle

03/26/2008 5:01 AM

You are not thinking this through my friend!!

That is the way the diameter of the guns bore is measured only, it actually fires shot, probably BB size or maybe bigger......although I have never been Duck hunting with such a gun, only read about it!!!

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#54
In reply to #48

Re: Foot pounds energy in Air Rifle

03/26/2008 4:58 AM

If someone is told he is a "Bore", does that imply that his Testes each weigh 1 lb?

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#57
In reply to #54

Re: Foot pounds energy in Air Rifle

03/26/2008 7:27 AM

Only if he has four of 'em, I think...

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#58
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Re: Foot pounds energy in Air Rifle

03/26/2008 8:36 AM

...walking must be a problem!!

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#59
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Re: Foot pounds energy in Air Rifle

03/26/2008 9:02 AM

I can only imagine...

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#64

Re: Foot pounds energy in Air Rifle

08/27/2008 10:02 AM

Foot pounds of energy for an air rifle or air pistol are calculated as follows:

mass of the pellet (in grains) x velocity in feet per second squared

divided by 450240.

Same works for bows, atlatls, blowguns, slingshots, firearms, etc.

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