Action type and physics

[1911Tuner]

Ahhh! You just don't wanna accept what your eyes are tellin' ya.

First, there was no way that 10 grains and a cotton plug could possibly move the slide...but it did. You still don't believe that the bullet is the major player in the delay...but it is. I got faith in ya, though. the light will come on if ya think about it long enough.

Okay. It was an Arisaka. Been a while since I read it. The point was that the rifle didn't move. No recoil. The effect of bullet delay was taken to a level that completely blocked all barrel movement rearward...and if the barrel can't move rearward...the gun can't kick.

On the other hand...if he'd blocked the bullet by a method that was divorced from the gun, it would have recoiled...because the force would have pushed the rifle backward and the barrel would have been pulled off the bullet. At least, for a short distance. It's also likely that the barrel would have been ringed or bulged behind the bullet...but that's a matter of conjecture. I ain't gonna run the test to find out.

 

[RBANNON]

I am having trouble with the bullet drag explanation and the effect upon the function of the 1911. If the barrel/breach, and cartridge are isolated as a system, it seems to me, that when all the forces are resolved, the following occurs. There is the pressure or force pushing on the base of the projectile mass and the barrel/breach. This results in the acceleration of the the projectile mass and c/g of the expanding gas in one direction and the barrel/breach in the other. The friction between the projectile mass and barrel/breach results in the acceleration of the projectile mass and barrel/breach in their respective directions, to something which is less than the theoretical acceleration for each. To the observer outside of the system, the net effect is that respective velocities of the projectile and barrel/breach are less than theoretical. Is this difference between the theoretical and actual acceleration, the projectile/barrel drag that is being referenced? Is the drag more important than the mass of the barrel/breach in delaying the unlocking? Sorry, if I am missing something that has been explained before. Thanks

 

[1911Tuner]

RBANNON...Wow. I don't know if I can follow all that...but I'll try to resolve your confusion with another analogy/hypothetical thing.

Let's morph you down to a tiny size...small enough to sit between a projectile and a breechblock. Forget the case for a minute.

Let's also give you superhuman strength. You're so strong that you can accelerate the
bullet and breechblock at normal velocities. Let's also give you arms that elongate, so that you can push the bullet completely out of the barrel.

If you stand between the two interacting objects and push...you feel a resistance on both arms. One from the drag between bullet and barrel...the other from the slide pulling the barrel backward on the bullet.

Now...go back to the normal operation of the ballstic event and consider what we know:


1. We know that the bullet and the barrel are moving in opposite directions at the same time. That's a given.

2. We know that the slide ain't gonna stand still...wait for the bullet to leave...and then move. That's another given.

3. We know that the bullet ain't gonna stand still until the barrel and slide finish their thing...and then take off.

4. We especially know that the bullet ain't gonna start...stop...wait for the slide and barrel...and then take off again.

We know that it takes a lot of force to push the bullet through the barrel. Therefore, it only stands to reason that it requires the same level of force to pull the barrel backward over the bullet...which brings us back to square one.

Whatever frictional resistance the barrel offers to the bullet, the bullet offers to the barrel...and...whatever resists the barrel's rearward movement also resists the slide.

Do the broomhandle trick that I outlined earlier. It'll start to make sense after a few times.

I know that it's hard to visualize because things are moving fast and the bullet's drag and delay only lasts for 1/10th inch of slide travel...or less. But if the bullet and barrel are moving in opposite directions at the same time...it has to work that way.

 

[huduguru]

Wow Tuner, still on the bullet friction locking kick, huh? The simple fact of the matter is this:

1) round is fired
2) ignited round exerts pressure on breech face, pushing slide and barrel
in opposite directions under pressure, "locking" slide lugs and barrel lugs.
3) slide begins to move a slight amount as bullet is still in barrel
4) pressure drops as bullet exits muzzle
5) slide and barrel(locked as one unit) continues to the rear due to recoil
forces (it is "recoil operated")
6) barrel links down from slide, allowing slide to continue

I have been reading some old posts on this "friction locking" and I thought
a poster by the name of "SDC" had proven that this friction locking was false.
The barrel and slide lugs stay locked together because of pressure on the breech face forces the slide and barrel together as in the xray of the firing 1911. The slide is "pulling" the barrel back and the only thing that delays it
is the fact that the slide moves many times slower than the bullet that's speeding out of the barrel.

I saw a question poised to you as to why a
bored out barrel with minimal friction still functions 100% but you never answered it. I also saw a post where you stated it was in Mr. Brownings
patent, but you could never post anything from the patent that
showed that "friction" was a major factor in locking the breech. In fact you
say; "The bullet is the main delaying factor in a locked-breech pistol due to frictionally-induced forward drag on the barrel. This is the one that so many overlook." The "main" factor? Where does it say this in Brownings patent? And why does a smooth bore 1911 function normally? Why isn't the 1911
called a "friction lock".

Also, didn't some guys here take some readings as to how much force it took to ram a fmj down
a 1911 barrel and it came out to be about 5% of the total psi involved in cartrdge firing? How
is that a "main factor" in locking

 

[1911Tuner]

Sure am, guru...because it's a fact.

The slide doesn't require a lot of force to drive it without the bullet's influence. Load a blank with 7-8 grains of Bullseye and a tuft of cotton and see for yourself. You can hand-cycle the slide faster than it moves when the gun is fired.

In case you didn't get it the first 15 times, I'll try again.

The barrel offers frictional resistance to the passing of the bullet. Whatever frictional resiistance the barrel offers to the bullet, the bullet offers to the barrel. The barrel has to move backward WHILE THE BULLET IS MOVING FORWARD...each one resisting the other's movement. Regardless of how short that distance is...while they're moving in opposite directions...both motions are being resisted by the other.

The barrel engages vertically...but it locks horizontally when the gun fires....

AND...

It does say so in Browning's patent. If you'd taken the time to actually read it, you'd have seen it.

Cheers

 

[huduguru]

You still haven't answered my questions. This is what you did in other threads also. Where is the SPECIFIC wording about friction locking
that Browning includes in his description? Also why does the smooth bore
1911 function with minimal friction of the bore?

This is the thread I was talking about:

http://www.thehighroad.org/showthread.php?t=290427&page=13&highlight=1911+vector

Do you have any numbers to back up your statement that the friction
in the barrel is "the main factor" in locking? If that's the case then
a smooth bore 1911 would basically be a blowback, correct?

 

[1911Tuner]

Guru...I never said that it "friction locks." That's your interpretation...your words.

It pressure locks. Barrel under forward drag by bullet friction. Slide driven backward due to force applied. Lugs are engaged in opposing directions. Barrel is pulled backward by the slide due to lug engagement...or pushed, depending on your perspective. Barrel is resisted by bullet drag. Whatever resists the barrel's movement resists the slide's movement...because the slide is taking the barrel backward with it...at the same time that the bullet is moving forward through the barrel.

Again...The locking description is in the original patents. Go and find it. It's there.

Imagine this:

If you had a bullet lodged in a barrel...and the bullet had a cable through the center of it...and the cable was attached to a wall...how much force would you have to use in order to pull the barrel off the bullet?

Now go find it in the patents.

 

[SaMx]

1911tuner is right, pressure in the barrel would push the breechface, and thus the slide back, but not the barrel. The only force acting on the barrel is the friction, which acts in the opposite direction.
I don't know if the friction is the main factor, but it definitely plays a part.

 

[huduguru]

You said the barrel is pulled into lock("main factor") with the slide by friction of the bullet to the bore. That's not correct. It's locked into the slide through pressure from the firing cartridge. You still haven't answered my questions, by the way. Why does a smoothbore 1911 function normally when friction
is the "main factor" in locking?

I will search the patent also.

 

[huduguru]

SaMx, that's exactly what I said, but he said friction in the bore is the "main"
factor in locking. It is definitely not.

 

[JonF]

Shoot a string semi-auto and another string holding the action closed with your thumb on the operating handle or slide.

Can you actually do that--hold the bolt closed with your hand and not get hurt? Is this possible for the low energy .22lr only or can it be done with centerfire pistols as well?

 

[1911Tuner]

but he said friction in the bore is the "main"
factor in locking.

No, I didn't. I said that friction in the barrel is the main SLIDE DELAYING factor. It's more signifigant than all the others combined. More than the recoil spring. More than the mainspring. More than slide to frame friction. More than wind resistance...combined.

The lock comes from pressure trying to drive barrel and slide apart...prevented by the locking lugs under a shearing force.

Lock your hands in front of your chest and pull in opposite directions. Clue: Your hands represent the lugs in opposition....and each hand is resisting the other. That's how it locks. The gun isn't locked when it's static, in battery. It locks when it fires.

I'd suggest that you go find it in the patents again...but at this point, I don't think you'd believe Browning either.

 

[Dulvarian]

Ok, this is for 1911...

I have always felt that every semi-auto handgun I have ever fired has a 'preferred' grain weight projectile for a given powder load. This discussion on a friction force vs. time delay seems to firm up what I have always thought 'because dammit, it seems right'. I always assumed that the deciding factor would be something like the twist rate on the rifling, but I guess that goes into the friction.

And reading this is just pushing me more in the direction of reloading so I can load up some for proving that theory.

And no, I would not want my hand in an x-ray that could go through even thin steel. Then think of how many shots it took to get that 'one'...

 

[huduguru]

If the friction is the main DELAYING factor as you say, then the aforementioned smoothbore 1911(that you conveniently failed to answer my question about again) would be a blowback correct?

The SLIDE mass(AND PRESSURE) is the main delaying force. It moves much slower than
the bullet. Get it? The smoothbore 1911 would not blow brass or show
any signs of premature unlock BECAUSE FRICTION HAS NOTHING TO DO WITH IT.

 

[1911Tuner]

guru...Any friction imposed on the barrel by the bullet would work to delay the backward acceleration of the breechbolt. Low friction...high friction...medium friction. The only difference would be in how much resistance and delay is imposed by the passage of the bullet. Even air offers friction. That's why meteors burn when they hit the atmosphere...and that's why bullets in flight slow down.

I'm gonna try this one more time, and then I'm movin' on to other comments and questions.

Imagine a cork in a pipe with a rope attached to the cork. Tight fit, but moveable through arm strength. One hand on the pipe and the other on the rope. Pull them apart. As the cork starts to move, so does the pipe. Keep pulling and keep them moving. The cork is being resisted by the pipe and the pipe is being resisted by the cork...because they're in contact and moving in opposite directions. Simple.

The cork is the bullet. The pipe is the barrel. Your arm...locked to the barrel by your grip...is the slide. The slide arm) is being resisted in its travel...by the bullet(cork) and friction provides the resistive force. Because your arm(slide) is resisted in its rearward acceleration...it's being delayed. (slowed)


Newton 3 works in both directions...whether pushing or pulling. Friction works in both directions, too. Whatever friction is imposed on one is imposed on the other. When you slide a steel block across atable, both table and block "feel" friction. Friction is a resistive force

And, just to wring your head up a little tighter...A straight blowback pistol is also recoil operated. The only difference between the blowback and the recoil operated pistol is the method used indelaying the opening of the breech. Aside from that, they both function as a result of force forward and force backward.

Be well.

 

[1911Tuner]

Duvlarian...The short recoil operated pistol only provides acceleration on the system for a brief instant. The slide moves nominally about a 10th inch when the bullet exits. When the bullet exits, all force is removed from the system, and neither bullet nor breechbolt...the slide...are feeling acceleration. All further movement is due to momentum. The slide gains speed...and momentum...during the time that the accelerating force is on the system. Recoil is nothing more than backward acceleration.

Most of what we perceive as recoil is actually momentum that results from the recoil impulse and acceleration of the gun. The true recoil is over so quickly, that our brains don't have time to realize that it happened before we detect momentum. Remember...Once the force is removed, there is no more acceleration.

If a bullet of a given weight is driven to a given velocity, that means that it had to be accelerated to that velocity, and it's entirely possible that a bullet is actually moving faster before it exits the muzzle than at the muzzle...depending on several factors.

In order to drive it to a higher velocity in the same barrel length...more force is required to accelerate it to that speed. If a lighter bullet is substituted...the force requirement drops...and because force forward equals force backward...the lighter the bullet for a given velocity the lighter the recoil impulse. In order to obtain the same recoil impulse, the bullet must be driven harder...accelerated more quickly...with the resulting higher escape velocity.

Anything that resists the bullet drives up the force requirement...including a faster twist rate. Bullet X in a cartridge that is loaded to a maximum pressure in barrel Y with a 1:12 twist rate is safe. The same cartridge in Barrel Z with a 1:6 twist rate may not be safe. As resistance goes up, pressure spikes more rapidly. Think of it as a sudden bore constriction, and it'll make sense. That's why it's imperative to develop maximum loads in the gun that they're intended for. One little change...a .0005 inch tighter bore...and pressures could go into the red zone.

 

[Dulvarian]

I'm not looking for maximum loads. More precisely, I feel that each gun handles fractionally better with particular weight and powder charges. I am more looking at accuracy.

Not a pure guess, an observation of several thousand rounds of factory ammo. I would not say that I am an expert by any means, but I am rather consistent.

If you are saying that the frictional constants combine together to give a fixed delay when combined with the inertia of the slide and the strength of the recoil spring ... it would stand to reason that a particular grain weight of projectile and powder charge would give an optimal performance. Not just a single combination, but a separate combination for each make and caliber. It would also vary slightly based on individual wear, but it should work out to be fairly constant for each different make and caliber (not accounting for individualized modifications).

From the video you posted, shooting from a rest at about the 2:30 mark, there is the smallest of upward motion in the barrel before the bullet exits. That's pretty much what I am looking at. Basically, if you can have the bullet exit the barrel before slide starts to rise from the rearward motion from the recoil you should have an improved accuracy. Lol, well, that's the thought anyway.

 

[1911Tuner]

Ah! Okay. If we're on accuracy, then, yes. Most guns have a preferred load as to bullet weight, shape, powder charge...and even cases and primers.

The "recoil" spring doesn't really have that much effect on slide/breech opening delay. The mainspring actually has more effect.
Its static resistance...preload...is only about 8 pounds with a 16-pound spring. Compressing it an additional 1/10th inch isn't going to add a lot to that. Of course, any opposing outside force means something...but the spring doesn't figure that much.

Ned Christiansen once fired a Delta Elite repeatedly without a recoil spring without adverse effect on the gun.

The primary function of the recoil spring is stripping, feeding, and returning the gun to battery...not delaying or decelerating/buffering the slide. It does do that as a function of compressing...but that's incidental. It has to be compressed in order to perform its main function. I much prefer "Action Spring" to recoil spring...but it's been called that for so long that I just go with it.

On the video...Notice that the bulk of muzzle flip...which accounts for the felt recoil...occurs when the slide hits the frame? Before that, the gun moves very little.

 

[sfc_mark]

Even firing all guns at once, a WWII era battleship suffers no displacement laterally from it. Does that mean no work was done on the ship by the massive energy absorbed by it in firing 20,000 lbs of projectiles at basically high-powered rifle velocities (I believe around 3000fps)?

Perhaps not a good example, as seen in the picture linked below. A full broadside is a LOT of kinetic energy and overcomes the inertia of the ship enough to kick up a bit of sideways wake.

http://en.wikipedia.org/wiki/File:BB61_USS_Iowa_BB61_broadside_USN.jpg

 

[1911Tuner]

Mark...Exactly. It would serve also to bear in mind that the recoil of the guns not only has the mass of the ship opposing it, but the water that the ship is floating in as well...and after adding the surface area of the keel...that resistance is considerable.

Like pushing on an oak. You can't move it because you couldn't exert enough force...but that doesn't mean that the tree didn't have a force imposed on it.

 

[wishin]

1911Tuner

Thanks for the education. I'm seriously impressed.

 

[huduguru]

Didn't mean to come off so hard but and I appreciate the replies.
I just want to understand what you are saying. The friction of the slug
in the barrel is the single largest delaying factor for the slide/barrel,
correct? So, it would be safe to assume that the slide/barrel assembly
would move further back earlier in the bullets travel down the bore(maybe even far enough to unlock while the bullet is in the barrel) if the bore was smooth and friction minimized, correct? This would result in bulged and possibly blown brass since it is the single most important factor in slide delay(according to your theory).

I have not heard of this happening in the few instances I have read about here and on other boards. In fact, there have been reported nothing abnormal in the functioning of the 1911 with a smooth bore. This is because the momentum of the stationary slide(and hammer spring and barrel to a smaller extent) prevent the slide from moving except for a small amount while the bullet is in the bore. Keep in mind that the speed of the bullet is many times faster than the slide. The friction of the slug has a negligible effect.

As you have said, "believe the experiment, not the theory", or something to that effect.

 

[1911Tuner]

The barrel can't unlock while the bullet is still there and under pressure. Pressure...Force forward and force backward...with the lugs engaged in opposition is what locks it. Delaying the slide gives the bullet time to exit so that the presure can drop, and the breech can open without blowing the case.

Once the pressure is off the system, the lugs are no longer being forced together in opposition, and they're effectively unlocked. At that point, the barrel can be linked down and the breech safely opened. The unlock occurs before the linkdown point...not at the linkdown point. Again...the barrel being vertically engaged in the slide and the slide in battery isn't locked. It engages vertically, but it locks horizontally when the gun fires.

There are several factors that are at work in delaying the slide. Since the instant an object is set into motion, outside forces immediately begin working to bring it to a stop, and anything that can bring that about will do that eventually.

I think that the cork in a pipe analogy has flipped on a light for you. It has to happen.
The bullet is a tight fit in the barrel. (Friction) The bullet is moving in one direction and the barrel is moving in the opposite direction...at the same time. Whatever resistance that is offered to the bullet BY the barrel is also offered to the barrel by the BULLET.
Whater resists the barrel's movement resists the slide's. The slide is delayed. Note that "delayed" doesn't equate to "Stopped."


The pressure lock description is in the patents. I suspect that you found it. FWIW, I understood the lock function years ago. Hard to believe, but I only got into the original patents sometime last year. I can't recall, but I think the bullet-induced delay is also described, but it's in lawyer-speak and requires a little careful thought before it's clear.

 

[huduguru]

Actually, this "bullet induced" delay is not described anywhere in the
patents. I skimmed it carefully and did not notice this anywhere. Alot of what you are telling me I know already, for example:

"The barrel can't unlock while the bullet is still there and under pressure. Pressure...Force forward and force backward...with the lugs engaged in opposition is what locks it. Delaying the slide gives the bullet time to exit so that the presure can drop, and the breech can open without blowing the case."

I am fully aware of this basic operating principal. I never said I disagreed
with pressure locking. I just said I disagreed about the significance of bullet
friction on the operating; specifically, the delay of the slide/barrel assembly
after a round is fired.


The momentum of the stationary slide/barrel assembly is the main delaying factor in the slide's travel, along with resistance from the hammer and various frictional forces. The key to understanding this is the fact that the bullet
is traveling many times faster than the slide and is a fraction of the mass
of the reciprocating assembly.

I've asked maybe 4 or 5 times already; Why does a smooth bore 1911 show no pressure issues and functions normally if the friction of the slug in the bore
is the main factor in the delay of the rearward movement of the slide?

Why do you chose to ignore what is in my opinion the most important question?

 

[1911Tuner]

Look at it this way...

The only alternatives are:

The bullet exits before the slide moves, ala Kunhausen's Balanced Thrust/Force Vector" description. Newton 3 says that can't happen, and the X-ray pretty much disproved that theory.

Or...

The bullet starts...stops and waits until the slide and barrel finish their cycle...and starts again. That can't happen either.

Or...

The bullet and barrel are moving apart at the same time, each one resisting the other's direction of travel because they're being forced apart against the frictional resistance that each offers to the other. Go back to the cork in a pipe analogy...or rig up an experiment and do it. When you're pulling them apart, you feel a resistance in both directions. The cork makes it hard to pull the pipe and the pipe makes it hard to pull the cork. What happens in the locked breech pistol works the same way.

Because...

Force on one side of the system equals force on the other side. That applies whether it's a compelling force or a resisting force...whether pushing or pulling.

It's all about delaying the slide until the bullet escapes. Delay...to slow or retard a function or action until a later time.

Just for what it's worth...The friction induced delay is the hardest part of the function to understand and make understood. Because it happens so fast, and only affects the slide for a very short part of its travel, it's hard to grasp. Just because it happens fast doesn't mean that the friction and the resistance disappears. It can't. The two parts are in contact. Friction is a force that can't be ignored. High friction. Try to push a bullet through a barrel. Which direction does the barrel want to go? Forward. Which direction does the slide pull the barrel? Backward. The bullet is doing its level best to hold the barrel forward while the slide is pulling it in the other direction.