Strange physics question... (gun related, but kinda long)


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Dionysusigma
May 9, 2004, 07:56 PM
A.K.A. Dumb questions in kinetic energy transfer

As I was relaxing this afternoon, I was playing Deus Ex and good 'ol Doom 2 :D , and a thought came to me (at first, I thought it was just a headache, but with pictures).

:p

So anyway, there are two main types of energy, potential and kinetic, and both can exist in different forms. Potential energy can be anything from a mass held at a height, chemically stored, and so forth. Kinetic is light, motion, heat (particles in motion), etc.

Reading different threads on this board, I found that pistol calibers coming out of barrels that were longer than their original intended use (i. e., a 9mm from a 20" barrel) may actually be hindered by that added length by slowing them down. Likewise, larger calibers coming out of a much shorter barrel (7.62x54R out of an M44) can leave a lot of the powder unburned.

Kinetic energy can transfer from object to object, sometimes changing its form: Car tires (kinetic energy is their rotation) spinning on a concrete surface (friction) causes heat (another form of kinetic energy).

Also, the Heisenberg Uncertainty principle may apply as well--using a photon (light) to determine a particle's (friction, in a sense) location and/or state will invariably change that particle's state... example: You like to play pool in the dark, and have a glow-in-the-dark cue ball. The racked balls (which are not glow-in-the-dark) are the mass you are measuring with the cue ball. After the break, you know where the cue ball made contact with the racked set, but you have no idea where the numbered balls are now. The cue ball's energy (motion) is directly responsible for their change of state (motion, change of location, etc.)

Tie this into a gun: energy is put into the bolt/slide/whatever when you, the operator, charges the gun (kinetic energy). That energy is transferred into the striker/hammer, and stored as potential energy. That energy is released (kinetic motion) when you pull the trigger, causing the hammer to fall on the firing pin (kinetic motion) and detonate the primer and eventually the powder (chemically stored potential energy now being released as heat).

The gases inside the cartridge expand due to the heat, forcing the bullet out (kinetic heat/motion of expanding gases transferred to projectile). As the bullet moves down the barrel, the barrel gets hot (due to friction between the bullet and rifling, and heat from the gases). The bullet leaves the gun, followed by the expanding gases that propelled it, which results in (more often than not) muzzle flash.

That's what gets me. If a 9mm is hampered by a long barrel to the point it slows down, shouldn't there be no muzzle flash? If the projectile is being slowed, that tells me that the burning powder/expanding gases aren't doing their job, so to speak. They aren't pushing the bullet, so they must be losing their energy. Why, then, does the flash still happen? For that matter, why is it still comparably loud?

Someone please inform my ignorant self... why, oh why? :banghead: :( :confused:

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Preacherman
May 9, 2004, 08:05 PM
If a 9mm is hampered by a long barrel to the point it slows down, shouldn't there be no muzzle flash?
Not necessarily. There may be some grains of propellant still burning - it's just that there aren't enough of them left to produce enough pressure to accelerate the bullet any more. These few grains still burning may produce a muzzle flash.
For that matter, why is it still comparably loud?
The sound of the explosion is the same - it's got to come out somewhere! :D
Also, the Heisenberg Uncertainty principle may apply
Heisenberg? Heisenberg? Didn't we ban him from THR a few months ago? :confused:

:neener:

7.62FullMetalJacket
May 9, 2004, 08:25 PM
You are assuming that the amount and type of propellant is a fixed issue. The 9mm cartridge is designed to propell the bullet based upon certain limiting factors. Since the 9mm is "usually" fired out of a short barrel, the powder is designed to burn very fast so that the bullet gets maximum acceleration. Let's asume the desin barrel is 4 inches.

If you put that same pistol catridge in a carbine with a 20 inch barrel, you have not only a further bullet patch where it is being squeezed by the barrel (creating friction), but you have 5 TIMES the volume to fill. SInce the propellant is fast burning, most of the expansion occurs rapidly and the greatest acceleration occurs in the first so many inches of travel. After that, the volume of the chamber (barrel) is so large compared to design specifics that the small amount of gases are unable to create enough pressure to overcome the drag of the barrel on the bullet.

As Preacherman stated, the noise is coming out regardless. The flash comes from the last few traces of burning propellant.

SMGs use different ammunition that burns slower powder and builds much greater pressure to address your very problem.

Bog
May 9, 2004, 08:35 PM
Wonderful example of Logic being a way of Going Wrong with Confidence.

I have to hand it to you, Dionysusigma, your logic is flawless - but oversimplified.

The power in the cartidge burns at a specific rate. Sure, and fine, but the incandescence at the end of the barrel will be, as stated, the continuing combustion of that power, and indeed possibly barrel-oil burning, amongst other things (such as any wadding in the round, or anything) will contribute to muzzle-flash.

The gasses in the barrel, producing the "bang" will not have fully expanded in the barrel - hence the sequence of baffles in a suppressor, to allow said gases to expand fully behing the bullet. You'd need a darn long conventional barrel to permit total gas expansion before the round left the muzzle. That comparable loudness of which you speak is a litre off of gas coming out of a 10 centilitre vessel, and shoving a bunch of air our of the way in doing so. Sound is just compressed air, after alll.

Even then, if it's a faster-than-600-odd-miles-an-hour-round, it'll go "crack!" due to it's breaking the sound barrier.

Very good reasoning, Dion, all the same.

Standing Wolf
May 9, 2004, 08:46 PM
...the Heisenberg Uncertainty principle may apply as well...

Heisenberg may have felt uncertain, but the Warren Commission sure didn't.

Oleg Volk
May 9, 2004, 08:56 PM
Report will happen but, because of lower pressue at the muzzle, will be less severe. Compare NAA Mini Mag with 1 1/8" barrel to a rifle with an 18" barrel.

Muzzle flash will be reduced but probably still visible in low light. Steel-jacketed ammo might also throw sparks.

molonlabe
May 9, 2004, 08:57 PM
Heisenberg Uncertainty principle does not apply at a macroscopic level.

Archie
May 9, 2004, 09:19 PM
Muzzle flash is the external burning of whatever powder is left over. (And anything else combustable in the barrel, as Bog mentioned, but I'm trying to stay simple.) Some powder is always left over, from a three inch barrel or a thirty inch barrel. However, I am passing sure that the longer barrel will give less flash than the shorter. One would need either special camera equipment or light meters that I don't have to test this proposition.

Muzzle blast or report is caused by the shock wave generated by the pressure excaping from the barrel. 9x19 operates at a (peak) pressure of 35000 psi. Even in a 20 inch barrel, the pressure at moment of bullet release is pretty high, compared to the 14.7 psi of regular (sea level) atmospheric pressure. A soda pop can makes a "pop" when opened, and that pressure level is pretty low (comparated to a firearm).

I keep hearing the theory about rounds "slowing down" due to a longer barrel. The US Army manual for submachines shows a higher velocity from the 45 ACP M3A1 submachinegun than from the M1911A1 pistol. The M3A1 has a 10 inch barrel (someone correct me if I'm wrong, I'm not looking this up...) and the M1911A1 has a five inch barrel. So the round seems to be more efficient in the longer barrel.

Now let's go extreme (everyone put on a lab coat and a mad scientist monocle): We have a 30 foot barrel. All the powder in a 9x19 cartridge is going to either burn or refuse to burn. Boyle's Law shows the pressure at the muzzle of the 30 foot barrel is going to be 462 psi. (Based on a pressure of 35,000 psi at the end of a 4" barrel.) I'm pretty sure the bullet would leave the barrel, but velocity is going to be lowered.
By the way, for a 16" barrel, the residue pressure is 10,400 psi, and a 20" has about 8,400 psi left. Velocity is not singularly determined on pressure, as the amount of time being accelerated is also a factor. The 16 and 20 inch barrels both push for a longer period of time, but I don't know the formula to determine velocity from this information.

Now what I don't know: I've never done a test to see how much energy is required to drive a bullet through a barrel. Does the "longer push time" mentioned in the preceding paragraph overcome the fricton factor?

I don't have either a 45 ACP or 9x19 carbine to compare. I do have three .44-40s, a 3", a 4 5/8' and a 16" carbine. Perhaps I can get some information from those.

Anyone in the Los Angeles area with a pistol caliber carbine want to do some research? Let me know.

Oh. Submachinegun ammo. The US never made pistol ammo specifically for submachineguns. Nor is it likely any major power issued two guns in the same caliber that required separate ammo, like 9x19 pistols and submachineguns. It just does not make sense. Please do not include the 9mm Glisenti... that's another sad story altogether.

Feel free to remove your labcoats.

mete
May 9, 2004, 09:21 PM
Scientific studies of shooting have shown that after 10 seconds your ability to hold a gun steady decrease and becomes worse the longer the time. I think Heisenberg Principle describes that perfectly !!...Besides Heisenberg is one of the very few who had the smarts and courage to write a one page doctoral thesis !

P95Carry
May 9, 2004, 09:23 PM
With the not inconsiderable ''Mu'' - friction factor .. even if the initial acceleration is very rapid ... there still needs to be considerable pressure left in the barrel just as bullet emerges ... but lower than would still contribute to further acceleration. ''Velocity maintainance'' if you will.

There MUST always, be a pressure release if bullet makes it out the muzzle .. even if 4 feet long .... if it exits thru the results of powder burn and thus gas pressure, then .... has to be some residual left ... just may be much less ''bang'' ... and flash limited to completion, or not, of the propellant burn.

In 9mm .... a high pressure round .... fastish powders will almost usually have ceased active combustion and been exhausted ..... expanding gas is all that's left. Minimal flame but some bang!

Arc Angel
May 9, 2004, 09:25 PM
:D I can't believe I actually read this entire thread! Will somebody, please, tell me why I did this? By any chance could it be that, 'Heisenberg thing' - again. ;)

Archie
May 9, 2004, 09:25 PM
Tell me you're kidding. Please.

molonlabe
May 9, 2004, 10:20 PM
Heisenberg might have posted here.



or he might not have.

Dionysusigma
May 9, 2004, 10:22 PM
BogYou'd need a darn long conventional barrel to permit total gas expansion before the round left the muzzle.
P95CarryWith the not inconsiderable ''Mu'' - friction factor... even if the initial acceleration is very rapid... there still needs to be considerable pressure left in the barrel just as bullet emerges, but lower than would still contribute to further acceleration. ''Velocity maintainance,'' if you will.

There MUST always be a pressure release if bullet makes it out the muzzle, even if 4 feet long.

So, if there was such a barrel that allowed total gas expansion, the bullet would get stuck every time, right? All right, this makes sense now. :)

And, in the same theoretical universe, one could make a barrel several yards long that, when used with ammo loaded to exact specifications, could reach near total gas expansion only to have the bullet come out the end going a measly 1 fps. Report would still be there, although it'd be no louder than a bottle of champagne opening.

And the pressure of the air outside the barrel compared to the gas pressure inside would make a difference too, I suppose. If fired in a vacuum, what then?

caseydog
May 9, 2004, 10:55 PM
And as to the sound of things , unless the bullet were to really slow down or was designed to be subsonic, you're goin to have a "sonic boom".Ray

Oleg Volk
May 9, 2004, 10:58 PM
Another reason for using polygonal rifling in SMG barrels...reduced friction.

Standing Wolf
May 10, 2004, 12:08 AM
Heisenberg Uncertainty principle does not apply at a macroscopic level.

Thank you! That explains everything. I feel so much better now!

Truth to tell: I utterly loathed, detested, and despised story problems all the way through high school and my sole semester of college mathematics. Trains going east versus automobiles going west, quarts turning into milliliters, electron spins and mass: all of it made me give up in despair. I understood the Heisenberg principle well enough to pass a physics test in high school, but all my knowledge vanished into thin air before I even started college.

Arc Angel
May 10, 2004, 12:52 AM
:) Wow! I had no idea you guys were, all, so bright. I'll bet you could answer, almost, anything. OK, then:

(1) 'Which came first, the chicken or the egg?'

(2) 'Why did the chicken cross the road?'

(3) 'Was, 'Fuzzy Wuzzy' really fuzzy?'

(4) 'How many angels can fit on the head of a pin?'

(5) 'If 19 pigeons are sitting on a fence, 4 hop down onto the ground, and I shoot 2 of them, how many are left, actually, sitting on the fence?'

(6) 'Two rabbits are confined inside the same cage; one of them is, 'in heat'. Given a normal gestation period of 65 days and a typical birth rate of 8 to 10 bunnies per litter, with 2/3's of them female, how many bunnies will there be at the end of the year?'

NOTE: An envelope containing the correct answers has been locked inside a vault guarded by Arthur Anderson & Associates. (The former accounting firm for Enron.) The first person to get ALL six questions right, wins a free THR ball cap. The clock is running, guys, so ... . :D

P95Carry
May 10, 2004, 01:25 AM
Arc Angel ..... it really is time you got that prescription changed!!! :D :neener:

Mal H
May 10, 2004, 01:58 AM
1) The egg. The final gene mutation (evolutionary type of mutation) that became what we know today as a chicken had to occur in an egg.

2) To quote Albert Einstein - "Did the chicken really cross the road, or did the road move beneath the chicken?" In other words, how do we know the chicken actually crossed the road? Without that essential fact, we cannot truthfully answer the question posed.

3) Yes, Fuzzy Wuzzy really was fuzzy. Just 2 weeks ago, I found an old Fuzzy Wuzzy childrens book at a flea market in PA and was surprised to find that FW was printed with fuzzy stuff all over him.

4) None. All past accounts of angels have them human sized and unipositional, i.e., one cannot occupy the same space as another.

5) None. There are two reasons why: a) pigeons don't "sit" on fences, they stand on them; b) any remaining pigeons on the fence would have been frightened away by the gunshot.

6) Undetermined. It is not known if the other original rabbit was a male or female. Therefore there might be any number from 0 (the original bunnies could have died during the year) up to the maximum number allowed by your given facts which would be achieved if there were 10 bunnies in each litter and each female was immediately "with bunny" after the shortest time period possible for them to mate after their birth and all their offspring lived to maturity. Several of those factors were not included in the question.

Dionysusigma
May 10, 2004, 02:34 AM
Mal H, I agree with you on numbers 1, 4, and 6. However...

2) To quote Albert Einstein - "Did the chicken really cross the road, or did the road move beneath the chicken?" In other words, how do we know the chicken actually crossed the road? Without that essential fact, we cannot truthfully answer the question posed. And god forbid if we throw in Zeno's Paradox (the chicken can never actually finish crossing the road). "Why," however, denotes a philisophical question. And as my mind is more versed on "how" than "why," I shall go with the answer: Because its legs operated in their usual manner, advancing the poultry forward.

(3) 'Was 'Fuzzy Wuzzy' really fuzzy?' Nope. "Fuzzy Wuzzy was a bear, Fuzzy Wuzzy had no hair." Just 2 weeks ago, I found an old Fuzzy Wuzzy childrens book at a flea market in PA and was surprised to find that FW was printed with fuzzy stuff all over him.
We all know how accurate the media can be when telling a story. ;)

5) None... any remaining pigeons on the fence would have been frightened away by the gunshot. I'd have to disagree there. If the question stated one pidgeon, then it's likely the rest would have flown off, but two denotes either 1. a lack of intelligence, 2. the use of a shotgun, or 3. difficulty of hearing. Since pidgeons are rather stupid anyhow, and it's impossible to tell how a pidgeon's hearing is by only looking at it, we can only assume that it's a deaf flock of mentally challenged flying rats. My answer, therefore, is fifteen.

To keep this gun/THR related, was it Dave McCracken, and was he using an 870? :D

Preacherman
May 10, 2004, 01:05 PM
And god forbid if we throw in Zeno's Paradox (the chicken can never actually finish crossing the road).
Actually, the chicken was ambushed by Schrodinger's Cat before he got halfway across... :neener:

Mal H
May 10, 2004, 07:29 PM
Yes, but is that famous cat dead or alive? Yet again Heisenberg enters in the argument. ;)

JohnKSa
May 10, 2004, 08:28 PM
Try to push a new 9mm bullet down the barrel of your favorite gun by hand and you will understand why it's possible for the bullet to actually be slowing down in a long barrel even though there is considerable pressure behind it.

Also remember, that takes less energy than is required for an actual bullet. When the gun fires, a typical bullet is slightly expanded at the rear by the force of the pressure.

jamz
May 10, 2004, 09:27 PM
Since pidgeons are rather stupid anyhow, and it's impossible to tell how a pidgeon's hearing is by only looking at it, we can only assume that it's a deaf flock of mentally challenged flying rats. My answer, therefore, is fifteen.


Funniest thing I've read all day. :D :D :D

(We really need a LOL smiley)

-James

Michigander
May 10, 2004, 09:44 PM
Every post in this thread makes sense to me. :eek:

P95Carry
May 10, 2004, 10:04 PM
We really need a LOL smiley Jamz .. try one of these ....

http://www.bedford.net/design/images/smilies/lol.gif

http://www.bedford.net/design/images/smilies/rotfl.gif

or

http://www.bedford.net/design/images/smilies/lmao.gif



:D

molonlabe
May 11, 2004, 10:22 PM
Heisenberg was stopped for speeding.
The state trooper asks "Do you know how fast you were going?
Heisenberg replies "NO, but I know where I am.

Arc Angel
May 11, 2004, 10:50 PM
Every post in this thread makes sense to me. :eek:

:) Oh, my god! :D

Erik Jensen
October 26, 2004, 06:18 PM
Try to push a new 9mm bullet down the barrel of your favorite gun by hand and you will understand why it's possible for the bullet to actually be slowing down in a long barrel even though there is considerable pressure behind it.

I tryed this, and it fell right out the other end! :confused: :confused:




of course, my favorite gun is my 1911, but still..... :neener: :D

JohnKSa
October 26, 2004, 11:29 PM
Got to thinking about this and it is possible to get no report with a long barrel.

The bullet would have to be accelerated very rapidly at first and then its momentum would have to carry it through the rest of the barrel.

It's possible for the bullet to exit at a decent velocity with zero or even negative pressure behind it if it has sufficient momentum to carry it through the remainder of the barrel after it begins decelerating.

I think this would work best with heavy projectiles and large bore diameter. The bullet weight would keep the momentum high even as the velocity falls off, and the large bore diameter gives more space for the gases to expand into as the bullet moves down the bore.

ConcernedCitizen
October 27, 2004, 01:33 AM
As far as I know, there was a 9mm ammo designed for SMGs, called Hirtenberger. I heard it was loaded VERY HOT, and had a tendency to blow up guns on occasion. It might have been their 5.56 ammo that had problems, I can't remember exactly, but I heard all of their ammo is HOT.

As for the pigeon question, it says "If 19 pigeons are sitting on a fence, 4 hop down onto the ground, and I shoot 2 of them, how many are left, actually, sitting on the fence?"

That is a trick question, because it did not specify whether the 2 pigeons shot were on the ground or the fence.

Of course, that doesn't take into account the "deaf flock of mentally challenged flying rats" theory... :D

So, exactly how much is my 2 cents worth? :neener:

Harry Tuttle
October 27, 2004, 02:00 AM
de combustion consumes the air in the casing

when the bullet leaves the bore

the remaining fuel oxidizes in the free air

FNFiveSeven
October 27, 2004, 03:44 AM
gunpowder doesn't require oxygen from the air to burn. You can burn gunpowder under helium if you want, air has nothing to do with it.

mete
October 27, 2004, 06:49 AM
I just saw some recent research that proves that Albert Einstein was right - the world is warped !!!

Harry Tuttle
October 27, 2004, 10:29 AM
yes the gunpowder contains an oxidizer, but free air oxygen is a potential source for uncontained burning and sound generation

mfree
October 27, 2004, 01:47 PM
Here's a line of thought...

A bullet is accellerated to supersonic speeds in a barrel, i.e. faster than the speed of sound.

The pressure wave from the burning propellent is only capable of travelling at the speed of sound in the material in which it moves, which is the pressurized hot gas field in the barrel.

Wouldn't there be a point with long barrels where the momentum of the bullet would carry it past the pressure wave where it would then be under a negative pressure and *retained* by the pressure in the barrel? In the time frame we're talking about, the environment in the barrel is never really homogenous and the speed of fluid movements comes into effect....

....get this theory down pat, do the math, and you've got a way to devise the perfect barrel length for a given load :)

Brad Johnson
October 27, 2004, 02:00 PM
(1) 'Which came first, the chicken or the egg?'

- Who cares as long as they are served with a side of bisquits and gravy.

(2) 'Why did the chicken cross the road?'

- Because it was thrown.

(3) 'Was, 'Fuzzy Wuzzy' really fuzzy?'

- Not if he used the right conditioner.

(4) 'How many angels can fit on the head of a pin?'

- I lost 500 bucks on them in the playoffs, so who cares!

(5) 'If 19 pigeons are sitting on a fence, 4 hop down onto the ground, and I shoot 2 of them, how many are left, actually, sitting on the fence?'

- They were sitting on a fence and milling around on the ground, and you only hit two. Boy, are you a crappy shot.

(6) 'Two rabbits are confined inside the same cage; one of them is, 'in heat'. Given a normal gestation period of 65 days and a typical birth rate of 8 to 10 bunnies per litter, with 2/3's of them female, how many bunnies will there be at the end of the year?'

- None. Just after you posed the question I sold them and bought a llama.

Brad

JohnKSa
October 27, 2004, 09:17 PM
The pressure wave from the burning propellent is only capable of travelling at the speed of sound in the material in which it moves, which is the pressurized hot gas field in the barrel.I can't think how to explain why that's not right, but the speed of sound is not a limitation in this case.

carpettbaggerr
October 27, 2004, 09:37 PM
Heisenberg might have posted here.

or he might not have.
Schrodinger did both. And neither.

If a barrel is long enough, the shots can be very quiet
indeed -- especially if the rounds are subsonic.
http://a1460.g.akamai.net/f/1460/1339/6h/www.cabelas.com/cabelas/en/content/Item/22/49/61/i224961hz01.jpg

http://thehighroad.org/showthread.php?s=&threadid=93004&highlight=Hastings+barrel+extension

molonlabe
October 28, 2004, 09:03 AM
Mrs. Schroedinger to Mr. Schroedinger: What the hell did you do to the cat?
It looks half dead!

molonlabe
October 28, 2004, 10:53 AM
"Wanted, dead or alive : Schroedinger's cat."

molonlabe
October 28, 2004, 11:48 AM
Wanted, dead AND alive, Schrödinger's Cat.

molonlabe
October 28, 2004, 12:15 PM
Why did the chicken cross the road?

Since the wording of the question implies the absence of an observer
(else the fowl's motivation might easily be deduced), it is evident that
the chicken simultaneously did _and_ did not cross the road. In the face of
this, any speculation as to the bird's purpose must be viewed as mere
sophistry -- and as such is beyond the bounds of this discussion.

Until the actual act or non-act of crossing the road was observed,
the act remained a cloud of probabilities.

jefnvk
October 28, 2004, 12:38 PM
As far as I know, there was a 9mm ammo designed for SMGs, called Hirtenberger.

I do believe there is. I think the original post was refering to WWII. IN wartime, I could absolutely see using the same ammo out of SMG and pistol. But, in peacetime, for police use I wouldn;t see why there isn;t a special round. Ammo interchangability isn't so much of an issue to them.

benEzra
October 28, 2004, 12:45 PM
That's what gets me. If a 9mm is hampered by a long barrel to the point it slows down, shouldn't there be no muzzle flash? If the projectile is being slowed, that tells me that the burning powder/expanding gases aren't doing their job, so to speak. They aren't pushing the bullet, so they must be losing their energy. Why, then, does the flash still happen? For that matter, why is it still comparably loud?
Some muzzle flash results from the fact that some of the combustion PRODUCTS are flammable, but do not burn in the oxygen-starved environment behind the bullet. (The powder is self-oxidizing, but the combustion products aren't.) When some of those hot combustion products hit the air outside the barrel, they undergo further combustion and produce some visible flash. I think carbon monoxide and POSSIBLY hydrogen may be present in amounts sufficient to produce a flash. (And no, carbon monoxide poisoning isn't a problem because the CO is HOT and oxidizes to CO2 as soon as it encounters atmospheric oxygen.)

quote:
--------------------------------------------------------------------------------
The pressure wave from the burning propellent is only capable of travelling at the speed of sound in the material in which it moves, which is the pressurized hot gas field in the barrel.
--------------------------------------------------------------------------------

I can't think how to explain why that's not right, but the speed of sound is not a limitation in this case.
Actually, it is, but not the speed of sound in air; rather, the speed of sound in 35,000 psi, 1000-degree nitrocellulose/nitroglycerin decomposition products, which is WAY higher than the speed of sound in sea-level air. It is this factor that limits the ultimate speed of any gunpowder-driven projectile to under 7000 fps; the gas simply can't expand any faster than that, regardless of how light your projectile is.

JohnKSa
October 28, 2004, 10:20 PM
benEzra,

That makes perfect sense!

Thanks,

John

Brian Dale
October 29, 2004, 03:38 PM
{bullhorn} All right, molonlabe, put down the cat and the textbook, and step away from the chalkboard! {/bullhorn}

RJ357
October 29, 2004, 10:52 PM
There was an experiment done and published in a gun magazine to determine how much velocity would be lost in a long barrel.
I can't remember the results, unfortunately, but I seem to remember that it was quite a bit longer than a rifle barrel.
They had to weld together a few lengths of barrel stock to get the results.

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