How much power does the action consume

[terraformer]

Smokey, learn how to quote properly. Also, I am not even going to bother answering your whole comment since most of the comments rely on misinterpreting what I said.

I will make a few points.
1) If it was purely mechanical, then you are saying that a 1/10 of an ounce brass casing has the combined mass and kinetic energy to cycle the slide on its own. Think that through.
2) I never said friction was not at work here, but your assertion that friction is what is causing the barrel to hold forward by the mass of the bullet is absurd. Why bother having a locking mechanism if it all magically happens in perfect timing? Also, if the force imparted on the bullet was singular, then the longer the length of the barrel would yield slower speeds on the bullet (because friction would be higher), though the opposite is true.
3) if the action wasn't operated on gas pressure, then compensators would neither work nor be needed.
4) In a blowback design (walther PPK), the gas pressure blows back the slide. In a locking design, the gas pressure blows back the barrel into the slide.
5) read up on how rocket engines work. Then you may get how recoil works.
6) grab a 1911 and take a dowel to push on the barrel. You will open the slide the distance of the barrel movement. Now imagine putting a very high amount of force on that barrel. It would throw back the slide most likely, right?

 

[HooVooLoo]

While physics discussions can be fun, we have veered way off the basic question the OP had asked...

Are guns ever rated for the amount of energy consumed by the action?

All mathematics aside...

The answer is, no. Firearms are not really rated in that way. Any "rating" depends on the ammo you shoot through it, and thus it is the ammo that is rated, not the firearm.

A fixed-bolt action will give you more projectile-energy out of the muzzle than a recoiling-type action, which includes inertial- and blowback-recoiling designs. That's about the gist of it.

Mallard...Now that you have experienced the NES version of an issue of Annalen der Physik, has your question been answered?

 

[smokey-seven]

Oooops

terraformer said:

Smokey, learn how to quote properly.

I know how, I was attempting not to embarrass you.

I will make a few points.
1) If it was purely mechanical, then you are saying that a 1/10 of an ounce brass casing has the combined mass and kinetic energy to cycle the slide on its own. Think that through.

I have thought it through. There is no gas pressure working on this action, it is completely mechanical, although the gas pressure is the original causing force of the mechanical action. The barrel recoils as well as the slide for a locked up period of rearward travel. This is mechanical and not pressure. The pressure has already been converted into mechanical.

2) I never said friction was not at work here, but your assertion that friction is what is causing the barrel to hold forward by the mass of the bullet is absurd.

Read what I wrote, not what you think I wrote. The barrel is moving in the OPPOSITE direction of the bullet because of friction as soon as the bullet starts to move. There is nothing in my comment to propose that anything else other than the recoil spring is holding the slide and barrel in a forward position.

Your words here.

It is the pressure inside of the barrel holding it forward and the slide backwards (again from the pressure built up inside the plugged barrel) that leaves it locked up.

Again I say nay. The only thing holding anything forward is the recoil spring which starts to compress as soon as the mass of the slide and components is superseded.

Why bother having a locking mechanism if it all magically happens in perfect timing?

The pivoting toggle is the perfect timing both in distance and time. That took some serious engineering. The barrel and slide remain locked together so that the expanding gasses have time to dissipate out the front before the action unlocks and allows extraction and ejection.

Also, if the force imparted on the bullet was singular, then the longer the length of the barrel would yield slower speeds on the bullet (because friction would be higher), though the opposite is true.

I have no idea what that was meant to say. Greater frictional resistance in a longer barrel is a fact. Are you saying it is not? Are you trying to tell me that if I put a 28" barrel on a 1911 and used the same ammo, that the speed of the bullet will increase? That's crap and you know it.

3) if the action wasn't operated on gas pressure, then compensators would neither work nor be needed.

They put compensators on pump shotguns. Are they gas operated? What's that have to do with the price of lemons? Compensators are a whole new topic.

4) In a blowback design (walther PPK), the gas pressure blows back the slide. In a locking design, the gas pressure blows back the barrel into the slide.

Not when they are locked together, they work as a unit until disengaged. The brass casing is pushing on bolt face as well as the barrel recoil forces. Are you talking air guns here? (Walther) I thought we were talking recoil activated firearms.

Look... Take a fixed breech muzzle loading cannon. Load it up with powder and ball. Stick a fuse in the touch hole and light it. There is NO GAS PRESSURE working on the recoil of anything and yet the cannon rolls back. That is a converted mechanical force. The kinetic energy mechanical force is the RESULTANT of the pressure increase. The slide and barrel of a 1911 are the same since the moving parts are free to move rearward.

5) read up on how rocket engines work. Then you may get how recoil works.

I was working nuclear ballistic missiles probably before you were born. Don't get sarcastic. I am dearly trying not to do that with you.

6) grab a 1911 and take a dowel to push on the barrel. You will open the slide the distance of the barrel movement. Now imagine putting a very high amount of force on that barrel. It would throw back the slide most likely, right?

I told you last post, hit the muzzle with a hammer and you will drive them both back and they will separate and the slide will continue. The bullet and expanding gas start the whole slide, barrel and other components rearward as soon as the mass of all parts is overcome and that is well before the .0007 second time. The, "hammer" in this example is the explosion which acts in all directions equally. The bullet is pushed out the front and the resultant recoil mechanical action, not gas pressure, is the equal and opposite force.

Now are you still trying to tell me that the slide and barrel are staying put till the bullet has left the barrel? The whole reason of having a locked barrel to slide is to allow the time for the pressure to dissipate to the degree that the extraction process will not have a nasty quantity of gas blow back from the back of the barrel in the direction of the shooter. Barrel pressure has been reducing ever since the bullet left the muzzle well before extraction.

Your original words:

Also the pressure needed to lock the slide to the barrel needs to be sufficiently high enough that the lock releases WELL BEFORE the pressure in the barrel has dissipated so that remaining pressure is able to toss the slide back.

Again, no.

The only thing holding the barrel and slide together after detonation is inertia and then they are separated by the toggle pivot, since the recoil spring tension has been already been over ridden by mechanical energy before that point.

 

[smokey-seven]

HooVooLoo said:

Mallard...Now that you have experienced the NES version of an issue of Annalen der Physik, has your question been answered?

LOL... thanks for that.

 

[terraformer]

OK, then answer me this. To fire a blank cartridge out of a real semi auto handgun*, you need to restrict the gas flow out of the barrel. Once that modification is made, the action cycles exactly as it would with real bullets. If a recoil operated gun is recoil operated based on equal and opposite force from the bullet and not pressure, then how is this possible? Why would restricting the opening on the barrel matter?

* Rifles require restriction too but they work on a different principle.

 

[strangenh]

Terraformer: Think of a recoil-operated gun as a car with a mattress on top. The mattress is the slide. The car starts off still until the explosive impulse sets it in motion. The mattress is locked to the car until after the impulse setting the car in motion is pretty much complete. So after the majority of the impulse, the car and mattress are already in motion, as a unit, all at one speed. Then the mattress is unlocked from the car body. Perhaps there is a touch of residual gas shooting out the barrel, but the real place the action is going to be made to work is from what the recoil has already set in motion. The brakes are the shooter's grip, exerting a counterforce. So the mattress and car are no longer coupled, and the shooter's grip is decelerating the recoiling gun. What happens when the brakes are applied? Right? Blowback is a different principle, since it indeed moves the slide based on the force exerted by the gas. Perhaps this example also helps one understand the effect of limp-wristing?

The advantage of blowback is that it can operate a bolt/slide in a system with very low recoil impulse. The advantage of locked breach recoil operation is it provides very consistent impulse to the bullet and loses no energy by dropping pressure from the chamber opening up.

I've never fired a blank from a recoil-operated gun, but I am pretty sure there is often more adaptation required than just muzzle restriction. For example, cutting off the locking lugs.

See for example: http://www.thehighroad.org/archive/index.php/t-32266.html (3rd comment down)

 

[terraformer]

I know what recoil is and what causes it. Yes, you need to round over the locking lugs on a 1911. I was actually going to say that to give him a hint. Ask yourself, why would you need to do that after restricting the barrel. The answer is it causes the barrel to not want to unlock because there is forward pressure on the barrel caused by the gas pressing on the restricton ring.

If you can pull the slide back and have the locking lugs disengage you can cycle the firearm. It still doesn't explain how you can have it cycle it with gas pressure without a bullet if this guys theory is correct. It's not. Recoil is not just the opposite reaction/ conservation of energy. There is something else at play and just because people here don't think it matters, it does.

 

[smokey-seven]

OK, then answer me this. To fire a blank cartridge out of a real semi auto handgun*, you need to restrict the gas flow out of the barrel.

In a word, no. This is not correct. I can fire a blank out of a 1911 and if I load the blank up to a point that it will cycle the action, it fires and cycles just fine. Where is the "restriction" in the barrel? What? A 1911 Colt is not a real semi auto handgun?

The answer is it causes the barrel to not want to unlock because there is forward pressure on the barrel caused by the gas pressing on the restricton ring.

What is a

restricton ring

?

The only forward pressure on the barrel is due to the recoil spring pressing the slide forward and in turn the barrel. As I have stated before, the barrel moves to the rear as soon as the bullet starts to move.

The gas does not press on anything else other than the barrel, bullet and the cartridge case. If it's a blank, there is no bullet, but it will still function provided there is enough powder in the explosion to cause enough recoil. If you loaded a blank with the same powder load as a standard 230 grain load and capped the cartridge with cardboard to hold the powder in the shell, there may not be enough pressure to convert the energy into mechanical force to operate the action. All forces have, after the explosion, been converted to mechanical energy.

It still doesn't explain how you can have it cycle it with gas pressure without a bullet if this guys theory is correct.

Please listen. Gas pressure is converted to mechanical energy. It is the mechanical energy that functions the 1911 and not gas pressure. Gas pressure is the origin of the mechanical energy but it is not what is working the weapon's action. What is working it is a reactive force of mechanical energy.

In your example of the blank, the pressure in the barrel is dropped if the shell is loaded equally and capped with cardboard compared to a fully, bullet loaded shell. You may have to load the shell up a bit to get a full functioning action and have the gas pressure converted to mechanical energy, but it will function with no bullet. The back end of the pipe is sealed, the front is open. The pressure builds and makes a bang and there is a reactive force pushing rearward equal to the amount of force escaping out the front.

 

[terraformer]

A SA will not cycle properly without first restricting the barrel as the gas pressure does not build up high enough without something to plug up the barrel.

Gas pressure is converted to mechanical energy. It is the mechanical energy that functions the 1911 and not gas pressure. Gas pressure is the origin of the mechanical energy but it is not what is working the weapon's action. What is working it is a reactive force of mechanical energy.

You still have not identified the source of the reactive force in the case of a blank in a SA pistol. There is nothing but gas expansion going out the front of the barrel. There is no bullet being pushed. Because there isn't any reactive force beyond gas pressure, yet it works if you restrict the barrel and ground off the locks.

The whole way to create a blank firing pistol from a real one is to place a plug into the chamber and drill out the center (creating the restriction ring). This does two things, ensure the firearm won't chamber real ammo and creates a restriction to allow gas pressure to build inside the chamber. But you also need to cut the locking lugs or round them over for this next reason (which is germane to where this whole CF started in the first place). When the powder burns, it increases pressure inside the chamber pushing in all directions, but there are two directions that are both "weaker" (in that they move) and on two separate masses. The back of the chamber which is the breach face on the slide and the front which is the restriction in the chamber (either the ring or the bullet). The pressure will push the barrel one direction and the slide the other, hence how the lock works to begin with. It is a pressure actuated mechanical lock as I said pages ago. The pressure on the bullet acts in one direction and the pressure on the breach face in the other and they counteract each other (because the barrel is locked to the slide) until the bullet releases from the barrel creating an opening for the gas to escape. That gas then can push on the slide and barrel in the backwards direction unimpeded. Recoil.

In the case of the bullet the pressure rises very fast and then drops very fast because at one point there is a near absolute plug in the barrel and at another instant there is nothing. In the case of the restricted blank barrel, the pressure builds slower and drops slower because the restriction is constant but not (near) absolute, hence the need to ground off or round over the locking lugs. If you didn't, the barrel would stay locked until there was not enough pressure to cycle the slide.

You have twice referred to the ignition of the cartridge as an "explosion". That is not correct. Cordite burns very fast and creates pressure. I question if you understand that a bullet is pushed along by gas pressure pushing it and not by a singular "explosion". It's the containment and direction of the pressure out of the barrel that causes the audible crack.

I have no idea what that was meant to say. Greater frictional resistance in a longer barrel is a fact. Are you saying it is not? Are you trying to tell me that if I put a 28" barrel on a 1911 and used the same ammo, that the speed of the bullet will increase? That's crap and you know it.

Although a 28" barrel is an extreme example which I won't speak too, most around here no that longer barrels increase the speed of the bullet because it allows more time for the gas pressure behind the bullet to push it along. It is a well known characteristic for reloaders to play with.

 

[smokey-seven]

A SA will not cycle properly without first restricting the barrel as the gas pressure does not build up high enough without something to plug up the barrel.

You are incorrect.

You still have not identified the source of the reactive force in the case of a blank in a SA pistol. There is nothing but gas expansion going out the front of the barrel. There is no bullet being pushed. Because there isn't any reactive force beyond gas pressure, yet it works if you restrict the barrel and ground off the locks.

No. It works because there is an equal and opposite reaction to the detonation. Grinding off the lugs is not in the equation. Loading the blank to the same barrel pressure to cause enough recoil mechanical energy to effect complete cycling is required.

The whole way to create a blank firing pistol from a real one is to place a plug into the chamber and drill out the center (creating the restriction ring)....

That's crap! Creating a blank firing weapon out of a 1911, needs only one thing. Load the blank up to the point where there is enough pressure in the barrel to create the mechanical force transference rearward in the slide. Yes it is doable, has been done and will ever be possible. Ask someone to demonstrate.

In the case of the restricted blank barrel, the pressure builds slower and drops slower because the restriction is constant but not (near) absolute, hence the need to ground off or round over the locking lugs. If you didn't, the barrel would stay locked until there was not enough pressure to cycle the slide.

No. See above. In actuality, IF there was a restricted barrel, the pressure would act opposite of your suggested thought and build faster.

If you didn't, the barrel would stay locked until there was not enough pressure to cycle the slide.

In reality, if the load was too light, the barrel can still unlock from the slide but the slide may not have enough kinetic energy to fully cycle. Pressure is not in this equation since it has already been transferred to rearward mechanical energy. It becomes a lack of mechanical energy.

You have twice referred to the ignition of the cartridge as an "explosion". That is not correct.

If you think that a cartridge detonation inside a barrel is not an explosion, then what the heck is it? I will continue to request this answer.

Cordite burns very fast and creates pressure. I question if you understand that a bullet is pushed along by gas pressure pushing it and not by a singular "explosion".

Explosions happen over time. It is a singular event but takes time to complete. Ever think that there are other powders than cordite?

It's the containment and direction of the pressure out of the barrel that causes the audible crack.

No it is not. It is the speed of sound of the expanding gasses being exceeded during the explosion that makes the bang. You cannot suppress the sound of a bullet that travels beyond the speed of sound, but you can suppress the, "bang" of the expanding powder by reducing the sonic wave to below the speed of sound over a longer time period.

What is a,

restricton ring

? I'm still waiting for an answer to that one.

Quoting me,

Greater frictional resistance in a longer barrel is a fact. Are you saying it is not?

[/quote]Although a 28" barrel is an extreme example which I won't speak too, most around here no that longer barrels increase the speed of the bullet because it allows more time for the gas pressure behind the bullet to push it along. It is a well known characteristic for reloaders to play with.[/quote]

You obviously will not respond to a simple fact that the longer barrel does have more frictional resistance than a shorter one. It's impossible to refute.

You are sadly unaware of different powder burn rates, and the time curves they take for the total burn of powders, (front loaded as opposed to back loaded) as well as differing pressures. I reload and I do not, "play". It is the combination of powder, casing, primer and projectile that determine muzzle velocity and it has noting to do with barrel length until you do the complete math for the chamber fit, bullet seat, burn rate, pressure curves, bullet mass, twists per foot AND barrel length and compensators and effects like humidity and temperature. Taking one cartridge and putting it in another weapon with a longer barrel will not necessarily increase or decrease the muzzle velocity. There are many other factors to consider. It could go in either direction depending on the weapons.

How's my quoting going these days?

 

[TheRoland]

The back of the pressure chamber is the breach face which is on the slide. So you have the barrel on the sides, the bullet in front and the slide in the back. That is how the barrel and slide pull against each other.

When fired, the PRESSURE of the powder burn pushes not only the bullet out of the barrel, but also holds the barrel forward (the bullet is acting as a plug), causing that lock to not be able to release.

I don't want to get into the minutia of the arguments you've moved to with Smokey, but I think this is really the fundamental disagreement behind the whole thing. You think there's a force that's holding the barrel forwards. I don't think there is (and this is Smokey's position, also).
Even in your replies, I still don't think you have described any mechanism which is moving (or applying a force) forwards on the barrel.

I think you can see this best if you draw a free-body-diagram of the barrel and the forces acting on it. This is a basic thought-tool which makes it easy to see where an object will accelerate, based on the forces applied. Let me draw a few; I'm going to leave out air resistance and gravity; if you think they're important, I can add them.

Let's start with one we can probably agree on: a firing bullet in a barrel looks like this (click for larger version):



F(pressure) is obviously the force on the bullet from gas pressure.
F(dynamic friction) is the bullet dragging on the inside of the barrel.

Excepting gravity and air resistance, this is all the forces acting on the bullet. Since F(pressure) is much higher, the bullet will accelerate left. We can do the same to the barrel and locked breachface, and, in fact, end up with mostly the same forces.



F(pressure) is the equal and opposite force from the bullet.
F(dynamic) is a equal and opposite force to the friction on the bullet.
F(spring) is the relatively small force from the recoil spring.

I assert these are all of the important forces in the system, and thus the barrel and breechface (and slide, which I think we agree are all still locked) must move rightwards. If you don't agree, could you point out where, on the diagram, I'm missing forces?

 

[terraformer]

I don't want to get into the minutia of the arguments you've moved to with Smokey, but I think this is really the fundamental disagreement behind the whole thing. You think there's a force that's holding the barrel forwards. I don't think there is (and this is Smokey's position, also).
Even in your replies, I still don't think you have described any mechanism which is moving (or applying a force) forwards on the barrel.

Your graphs are too simplistic and aren't labeled as to what's what. I get the bullet in the first, but it's not clear what the square is. Anyhow, this is what I am asserting in the most basic terms I can muster.

The force of the bullet (which acts as a plug) and gas pressure behind it pushing it inside the barrel stalls the slide from recoiling long enough to allow the bullet to leave the chamber. It stalls the slide because the two are locked together*. Once it is free of the barrel, the slide will move but not until that point is reached does the slide move. It is being held in place by the barrel and forces going in the direction of fire and only when the bullet is free of the chamber does the slide move rearward because the plug in the barrel is gone and the force of friction from the air is not sufficient to keep it forward. This is not some fancy timing thing in the pivot of the action.

I assert these are all of the important forces in the system, and thus the barrel and breechface (and slide, which I think we agree are all still locked) must move rightwards. If you don't agree, could you point out where, on the diagram, I'm missing forces?

I actually don't think we all agree on that part. If we did, then this conversation has been a waste of time. But again, someone here asserted that the timing and spring tension held the slide in place. If it was, that would be a blowback operated gun (similar to the PPK) and would not require the locking lugs. We don't disagree that x newtons of force in the bullet is matched by x newtons of force on the firearm. What we disagree with is the where, the how, the why and how much more the firearm absorbs than the bullet.


Emphasis mine below.

The force is being imparted from the instant the bullet commences its movement in the barrel to the time it leaves. The REACTION forces have been applied in the mass of the bullet moving forward and the rest of the assembly moving to the rear AS THIS HAPPENS. The force that accelerated the projectile to around 900 FPS over the length of the barrel has acted on the slide and barrel in the opposite direction during this time. The pressure drops as soon as the bullet is gone and it is now safe for the timing of the action to open the breach and extract the empty. There is a little residual gas expansion but the vast quantity of it is gone. Remember that the other end of that pipe is wide open as soon as the bullet leaves and it is long gone before extraction is made.

"So now that the barrel is not able to push forward with enough force to keep the lockup locked, the barrel begins to come backwards."

It's the spring tension keeping this thing locked up. The barrel does no pushing on closing, the slide pushes the barrel under spring pressure. The spring acts on the slide and that in turn pushes the barrel into the locked phase.

snip...

The, "pressure on the barrel" is there by virtue of the spring and slide holding it there.

snip...

The spring holds it closed and as soon as the mass of the barrel/slide mechanism has been over ridden by the force equal and opposite to the direction and force of the bullet, it begins the recoil action. The bullet is long gone but the force has been applied to the already moving components, it just takes time for the complete cycle to happen. Pressure in the pipe has nothing to do with it other than applying force in all directions equally until the bullet has left. Over the time of the bullet in movement in the barrel, (remember that .0007 second time?) the force has been applied to the weapon and things are happening from .0000 to .0007. At that point, the force has already been applied to all components.

* there's also mass issues of the barrel and slide here (ie; the slide is a significantly higher and sprung mass weight) but let's not confuse the issue.

 

[TheRoland]

In the diagram, the 'square' is the breechface (and thus, slide). I totally agree that the slide and the barrel remain locked, but I'm showing that the slide, cartridge, and barrel, do start to move immediately, as there is no such force in the direction of fire.

The force of the bullet (which acts as a plug) and gas pressure behind it pushing it inside the barrel stalls the slide from recoiling long enough to allow the bullet to leave the chamber. It is being held in place by the barrel and forces going in the direction of fire

But there is no such forward-facing force. The only forces acting on the barrel/breechface are the ones I've captured in the diagram (unless I've missed one).

By "force of the bullet" do you mean friction due to the bullet being pressed against the rifling? Because that's not sufficient to overcome gas pressure (which is why the bullet moves).

 

[smokey-seven]

terraformer said

The force of the bullet (which acts as a plug) and gas pressure behind it pushing it inside the barrel stalls the slide from recoiling long enough to allow the bullet to leave the chamber. It stalls the slide because the two are locked together*. Once it is free of the barrel, the slide will move but not until that point is reached does the slide move. It is being held in place by the barrel and forces going in the direction of fire and only when the bullet is free of the chamber does the slide move rearward because the plug in the barrel is gone and the force of friction from the air is not sufficient to keep it forward. This is not some fancy timing thing in the pivot of the action.

No.

This is not some fancy timing thing in the pivot of the action.

Yes it is.

 

[terraformer]

terraformer said

No.



Yes it is.

I just searched for "pivot link 1911" to see if there was ay evidence you were right.
http://www.google.com/search?client=safari&rls=en&q=pivot+link+1911&ie=UTF-8&oe=UTF-8

This is the first result returned.
http://www.m1911.org/locking.htm

Read the section entitled "Firing Phase A: Lugs horizontally engaged"

I win.

 

[Boghog1]

I have read through most and a good portion was over my head but couldn't you take the weight of the action and the resistance of the spring to come up with how much force is required to move the action? Also the powder will have a set amount of power available to propel the charge and actuate the action, normally loads are well above and a good portion of the powder charge is burned outside of the barrel. but you should be able to use math to figure out what amount of energy was used to get the bullet to muzzle velocity no?

 

[TheRoland]

http://www.m1911.org/locking.htm

Read the section entitled "Firing Phase A: Lugs horizontally engaged"

I win.

I was really, really hoping nobody would bring up Kuhnhausen's article. Kuhnhausen is a fantastic gunsmith, and may be a genius in all things 1911, but he's obviously no physisist. He is straight up wrong about the physical mechanics of the 1911s recoil operation. The section right after the one you sight, in particular, is a tangle of meaningless techno-babble with no physical mechanism to support it.

He says the slide doesn't move because of:

Firing is split into two phases because of the thrust vector existing between the bullet and the breechface

and only moves after

Bullet departure breaks the balanced thrust vector established when the bullet was in the barrel as in fig. 4A.

But this is not true. There is no physical concept of a "balanced thrust vector"; it's meaningless physics-sounding words strung together that sound good, sure, but it's not actually describing any physical process.

After this "thrust vector" is "broken", he claims, only then does this:

imparts a rearward force on the slide assembly equal to the inertia of the departing bullet.

First of all, he means momentum here, not inertia. Second, the rearward force is not equal to the momentum of the bullet anyways, as momentum and force are two different concepts (velocity vs acceleration). Third, this delay of Newton's laws is simply physically impossible.


So, in short, Kuhnhausen may be a very talented gunsmith (I'm told he was one of the best, ever), but his foray into physics is clearly incorrect.

EDIT: Apparently I'm not the only one that noticed this article was wrong at first inspection. I've found a couple threads on this at 1911Forum and elsewhere.

Here's a link to an x-ray picture someone took of a 1911 firing the shows it:

Notice the postion of the barrel link, which shows rear-ward movement. I did not know this existed until I googled it, but this shows exactly what I'm asserting.
I wish I had a high-speed x-ray camera.

 

[terraformer]

I did not quote him and didn't talk about "balanced thrust vector" or anything else. The source of energy in the barrel is the expanding gas. It imparts energy equally in all directions on everything in the barrel/chamber. The energy is pushing the bullet through the barrel which is in turn creating friction on the walls of the barrel. Until the bullet leaves the chamber, the barrel has a forward force on it. Even afterwards, the friction of the supersonic air traveling up the walls of the barrel will impart forward energy on the barrel. The barrel and the mass of the slide are vastly different masses. You need to impart vastly more energy on the slide to move it so that means you don't need to impart on the barrel the equal amount of energy you do on the slide to be able to stall the slide. Someone said that all energy is expended as soon as the bullet leaves the chamber. If so, then what happens to all of that gas escaping out of the front of the barrel? That doesn't impart anything on the firearm?

The key central question is this, "Why bother with the locking lugs?". It is clear that there is no need to lock the barrel to the slide if the slide and spring take all of the force. Not a single person besides me has explained the locking lugs. Not one.

Your trashing of this gunsmith is predicated on some folks on the internet. Explain the locking lugs and we can talk.

ETA: Hint. The chamber and barrel of the gun is a closed system until the bullet leaves the chamber. The energy inside the chamber can not in any way interact with anything outside of the gun. Therefore all of the forces inside the gun can only act on the gun itself. It is only when the bullet leaves that it can then interact with the mass around the gun.

Try this experiment. Get some tubing, a t-connector and two plugs. Cut the tubing into three pieces, two being equal lengths. Connect tubing to the t-connector with the equal length ones opposite each other. Plug the equidistant ones. Make sure the plugs are tight. Blow on the open one. Does anything move wildly? Blow harder until one plug pops. One plug will invariably pop before the other does (assuming wide variation in whatever material you use). When the first plug goes, the whole thing will swing away from that side towards the other. You just simplified what happens in a 1911.

 

[lupis42]

I haven't been following that closely because we seem to be getting more into the 1911 design, and that makes me want to buy a 1911, and I can't afford one right now, but...

Explain the locking lugs and we can talk.

The locking lugs (IIRC) serve to ensure that the barrel and slide move backwards together for a short distance. This keeps the chamber locked shut, which keeps the pressure in the barrel higher which means more force behind the bullet as it goes down the slide.

 

[Bob P]

I did not quote him and didn't talk about "balanced thrust vector" or anything else. The source of energy in the barrel is the expanding gas. It imparts energy equally in all directions on everything in the barrel/chamber. The energy is pushing the bullet through the barrel which is in turn creating friction on the walls of the barrel. Until the bullet leaves the chamber, the barrel has a forward force on it. Even afterwards, the friction of the supersonic air traveling up the walls of the barrel will impart forward energy on the barrel. The barrel and the mass of the slide are vastly different masses. You need to impart vastly more energy on the slide to move it so that means you don't need to impart on the barrel the equal amount of energy you do on the slide to be able to stall the slide. Someone said that all energy is expended as soon as the bullet leaves the chamber. If so, then what happens to all of that gas escaping out of the front of the barrel? That doesn't impart anything on the firearm?

The key central question is this, "Why bother with the locking lugs?". It is clear that there is no need to lock the barrel to the slide if the slide and spring take all of the force. Not a single person besides me has explained the locking lugs. Not one.

Your trashing of this gunsmith is predicated on some folks on the internet. Explain the locking lugs and we can talk.

ETA: Hint. The chamber and barrel of the gun is a closed system until the bullet leaves the chamber. The energy inside the chamber can not in any way interact with anything outside of the gun. Therefore all of the forces inside the gun can only act on the gun itself. It is only when the bullet leaves that it can then interact with the mass around the gun.

Try this experiment. Get some tubing, a t-connector and two plugs. Cut the tubing into three pieces, two being equal lengths. Connect tubing to the t-connector with the equal length ones opposite each other. Plug the equidistant ones. Make sure the plugs are tight. Blow on the open one. Does anything move wildly? Blow harder until one plug pops. One plug will invariably pop before the other does (assuming wide variation in whatever material you use). When the first plug goes, the whole thing will swing away from that side towards the other. You just simplified what happens in a 1911.

Lemme take a stab at this for a minute:

Ignore the gun and concentrate on the barrel. It's a tube. The cartridge is in the chamber at one end. The cartridge fires. Energy tries to expand in all directions. The barrel blockes it laterally. The case at the other end and the lugs lock up the slide so that's sealed too. So the path of least resistance is the bullet which starts to move down the barrel. YES, that provokes a reaction BUT at the same time the bullet is engaged in the rifiling. THAT creates friction which pulls the barrel FORWARD and cancels out the REACTIVE force backwards - until the bullet leaves the end of the barrel. THEN the reactive force is free to act on the barrel/slide.

 

[HooVooLoo]

If you think that a cartridge detonation inside a barrel is not an explosion, then what the heck is it? I will continue to request this answer.

If a cartridge detonates inside the barrel, thus "exploding", your hand becomes ground chuck. Today's powders do not detonate unless they are erroneously used in too small a quantity in a larger-capacity casing.

Cordite burns very fast and creates pressure.

Where do you find Cordite? That stuff is no longer used, heh.

Explosions happen over time. It is a singular event but takes time to complete. Ever think that there are other powders than cordite?

Small-arms ballistics occur strictly through deflagration, not an "explosion over time".

Doing a little research, I found that it seems that the escaping gases after the bullet has left the muzzle still have an effect on the bullet for a short distance outside. I guess that makes sense when you consider that the gases are escaping much faster than the bullet is travelling.

 

[lupis42]

Lemme take a stab at this for a minute:

Ignore the gun and concentrate on the barrel. It's a tube. The cartridge is in the chamber at one end. The cartridge fires. Energy tries to expand in all directions. The barrel blockes it laterally. The case at the other end and the lugs lock up the slide so that's sealed too. So the path of least resistance is the bullet which starts to move down the barrel. YES, that provokes a reaction BUT at the same time the bullet is engaged in the rifiling. THAT creates friction which pulls the barrel FORWARD and cancels out the REACTIVE force backwards - until the bullet leaves the end of the barrel. THEN the reactive force is free to act on the barrel/slide.

If the friction canceled out the reactive force acting on the slide, the bullet wouldn't move down the barrel.

 

[TheRoland]

I did not quote him and didn't talk about "balanced thrust vector" or anything else. The source of energy in the barrel is the expanding gas. It imparts energy equally in all directions on everything in the barrel/chamber.

Agreed, and sorry if put words in your mouth, that's not my intent.

The energy is pushing the bullet through the barrel which is in turn creating friction on the walls of the barrel. Until the bullet leaves the chamber, the barrel has a forward force on it.

Agreed. However, the forward friction is tiny compared to the rearward gas pressure. This can be shown because the bullet moves due to the exact same (but opposite) forces. The force from the gas on the breechface is the same quantity as the force on the bullet. The friction of the bullet is exactly the same as the friction on the barrel. The forces are the same. So if the bullet moves, the slide/breechface/barrel must too (because the forces are equal due to Newton's laws). Do you disagree with this? If so, I think I can prove this mathematically.

Even afterwards, the friction of the supersonic air traveling up the walls of the barrel will impart forward energy on the barrel.

Agreed, but this is even smaller than the friction of the bullet. It's not going to hold anything in place.

The barrel and the mass of the slide are vastly different masses. You need to impart vastly more energy on the slide to move it so that means you don't need to impart on the barrel the equal amount of energy you do on the slide to be able to stall the slide.

Full stop. I don't understand what you're saying here. There's no multiplier on the slide that tells it what the barrel's mass is. If you've got 0.1 Newton forward on the barrel from friction, and 10 Newtons backwards on the slide (and they're locked), you've got 9.9 Newtons backwards on the slide, regardless of mass.

Someone said that all energy is expended as soon as the bullet leaves the chamber. If so, then what happens to all of that gas escaping out of the front of the barrel? That doesn't impart anything on the firearm?

The gas escaping as pressure drops will cause a very small rear-ward force, far, far, less than when the bullet is in the barrel.

The key central question is this, "Why bother with the locking lugs?". It is clear that there is no need to lock the barrel to the slide if the slide and spring take all of the force. Not a single person besides me has explained the locking lugs. Not one.

To keep the breechface locked to the barrel until the bullet it gone. Not to keep the slide locked to the frame, as this is impossible.

Your trashing of this gunsmith is predicated on some folks on the internet.

I didn't mean to trash anyone, but he's wrong. I'm basing this on an education in physics.


There's a picture that proves my point that I added to the last post. What's your take on the picture?

 

[terraformer]

I haven't been following that closely because we seem to be getting more into the 1911 design, and that makes me want to buy a 1911, and I can't afford one right now, but...


The locking lugs (IIRC) serve to ensure that the barrel and slide move backwards together for a short distance. This keeps the chamber locked shut, which keeps the pressure in the barrel higher which means more force behind the bullet as it goes down the slide.

There are other ways to do that but at least you have given up an answer. The pivot on the 1911 is a circular arc. As movement occurs in the barrel there MUST be a gap at the breach face that opens up. That would allow pressure to escape.

Your idea also doesn't explain why the locking lugs need to be ground down to have blanks reliably cycle a 1911 sans modification. If the escaping gases can push the slide back, it stands to reason this is exactly the same as one grabbing the slide and pulling back.

Yet, you need to restrict the barrel in order to get the gas pressure high enough to push the slide back. As a result, it fails to cycle. Why? Because the gas pressure is stalling the barrel far longer than a bullet would. As a result, all of the gas escapes out the front and it is at that point like a firehose. Everyone here seems to be making the assumption that the 500 ft lbs of energy in the bullet equals the force on the firearm in the other direction. If that's the case, then that means the gasses escaping the barrel are not having a single impact on the firearm. If you go back, you will see that I mention this before when I talk of compensators. If all energy has been imparted by the point the bullet leaves the chamber, then the escaping gas has zero impact and that is impossible. It has an impact. Why? Because recoil is more than the force imparted on the bullet.

Firearms are not 100% efficient. The force on the bullet is some fraction of the total force expended. In a 100% efficient system it is 50%. It is less than 50% in reality.

 

[TheRoland]

Try this experiment. Get some tubing, a t-connector and two plugs. Cut the tubing into three pieces, two being equal lengths. Connect tubing to the t-connector with the equal length ones opposite each other. Plug the equidistant ones. Make sure the plugs are tight. Blow on the open one. Does anything move wildly? Blow harder until one plug pops. One plug will invariably pop before the other does (assuming wide variation in whatever material you use). When the first plug goes, the whole thing will swing away from that side towards the other. You just simplified what happens in a 1911.

The use of end-caps makes this deceptive. Instead of one cap, on one side, place a marble halfway down the tube. As the marble accelerates towards the end of the tube, but before it exits, the tube will accelerate in the opposite direction. That's a basic law of physics.

 

[HooVooLoo]

I just went for a smoke and it finally clicked in my head. Terra is correct. As the bullet is travelling down the barrel, it is actually "pulling" the barrel forward. By locking the breech to the rear of the barrel, it prevents the breech-face from moving backward the instant the bullet starts moving.

If in that set up the slide/breech was NOT locked to the barrel, a gap would immediatley form between breech and barrel, allowing gases to escape from the rear before the bullet has exited the barrel, reducing bullet velocity.

If you strip down a SA to the barrel and stick a bullet in the chamber, attempt to push the bullet through with a stick. You'll feel the barrel trying to move forward in your hand.

After the bullet leaves the muzzle, the barrel is then "pulled" back as the slide/bolt move back. After a teeny-tiny distance, the barrel hits a stop and the slide/barrel separate and complete the cycle. This is not to say that the energy imparted by gas pressure is not affecting all components the moment the bullet separates from the crimp. It simply means that the mechanical movement is, in fact, delayed.

And I didn't even have a V8

 

[TheRoland]

As the bullet is travelling down the barrel, it is actually "pulling" the barrel forward. By locking the breech to the rear of the barrel, it prevents the breech-face from moving backward the instant the bullet starts moving.

This is physically impossible unless the bullet is not moving.

The forward force on the bullet is the same quantity as the backwards force on the breechface. They are equal but opposite.

The backwards force on the bullet is the same quantity as the forward force on the barrel. They are equal but opposite.

So, unless there are other major forces at work, if the bullet accelerates at all forwards, the slide/breechface must accelerate backwards, and vice-versa.

 

[terraformer]

To keep the breechface locked to the barrel until the bullet it gone. Not to keep the slide locked to the frame, as this is impossible.

I never said it locked the slide to the frame, never. I said it imparted force to counteract the backward slide and only momentarily. I never said it locked it to the frame. I have begun to use the word stall as I think that best represents what is happening.


As for the picture, I would need to see a picture of the gun before the discharge and another with the locking lugs ground down before and after. By itself it just shows a slight movement in the barrel. The key is to see what not having the lugs does to the gun. The reason I say this is because there is no way to pull the slide back over the barrel without the barrel moving in unison. The top of the chamber won't allow it so the locking lugs are overkill for task.

 

[HooVooLoo]

This is physically impossible unless the bullet is not moving.

The forward force on the bullet is the same quantity as the backwards force on the breechface. They are equal but opposite.

The backwards force on the bullet is the same quantity as the forward force on the barrel. They are equal but opposite.

So, unless there are other major forces at work, if the bullet accelerates at all forwards, the slide/breechface must accelerate backwards, and vice-versa.

Yes, the forces are equal. But mass x velocity=momentum. While the mass of the bullet is tiny compared to the mass of the slide, the velocity is WAY WAY WAY more. Thus, the bullet accelerates much faster than the slide and thus has more momentum, which is how the bullet can go anywhere in the first place.

 

[terraformer]

This is physically impossible unless the bullet is not moving.

The forward force on the bullet is the same quantity as the backwards force on the breechface. They are equal but opposite.

The backwards force on the bullet is the same quantity as the forward force on the barrel. They are equal but opposite.

So, unless there are other major forces at work, if the bullet accelerates at all forwards, the slide/breechface must accelerate backwards, and vice-versa.

But not as much as it would without it. Do you have xray pictures of the 1911 further into the action?