Hydraulic recoil spring?

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Tuner, I can definitely understand why you are so good with dogs - you have more patience than I think I have ever seen in a human being. It's a pleasure to have you on this forum. Anyone who loves dogs like you do is OK in my book.
 
"How does this apply to the 1911 in particular, even? The 1/10th inch and 1/10 inch seems too convenient to where it might be incorrect assumption"
The guns are designed. It's incredibly likely Browning did some envelope calculations :rolleyes: (and then some). The principles of damped spring/mass systems were around for the Steam Age.

A successful/reliable gun design that seems right on the ragged edge of unlocking under pressure with even factory ammo, however --that might be the result of a bad/missing assumption.

TCB
 
Hmmm....double the barrel length to 10" and it only takes a bullet moving at ~800fps ~0.4milliseconds to cover the extra distance. At 5", the chamber pressure is ~3500psi and at 10", it drops to ~3200psi. The breech probably unlocks a tad early, and there may be some gas leakage around the case in that .4ms, but it probably isn't any worse than shooting a straight blowback .45ACP.
 
How does this apply to the 1911 in particular, even? The 1/10th inch and 1/10 inch seems too convenient to where it might be incorrect assumption
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Assumption? Too convenient?

Stop-action videos showing the bullet position relative to slide travel distance have been around for years. This is one of the better ones I've seen.

Where do you think I got those figures?

Or did you...assume...that I just pulled'em outta my...uh...watch pocket?

The 2nd post shows the entire sequence.

http://forum.m1911.org/showthread.php?106716-Kurzzeit-High-Speed-Video&p=969934#post969934
 
Now then...

We see that by the time the slide has moved approximately.100 inch, the bullet has traveled 4.3 inches.

(The barrel is 5.1 inches long, approximately .900 inch of which is chamber.)

If we assume that there's a direct proportion in the continued bullet to slide travel...by the time the slide and barrel have moved far enough for the lugs to vertically disengage... .200 inch... the bullet will be approximately 8.6 inches out. It'll actually be a little more because the springs...recoil spring and mainspring...immediately start to decelerate the slide when the bullet exits, but we'll stick with 8.6 inches for the sake of avoiding more pointless arguments.
 
Tuner, I can definitely understand why you are so good with dogs - you have more patience than I think I have ever seen in a human being.
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M'fren...I've got 23 dogs here, including 5 young, full-blooded Siberian Husky hooligans...3 yeehaa Pitbulls...and 6 10-month old puppies that came to me by way of a pretty little vagabond that I took in last May already in the family way. There were 8. Nobody stepped up for the others, so here they are. They're nice little dogs though...pretty as they can be, and just wicked smart.

And right now, 21 of the total are asleep in the house.

I'm eat slam up with patience.

Thanks for the good words.

And that is what I call optimism.
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I tries. Lord knows I tries.
 
We see that by the time the slide has moved approximately.100 inch, the bullet has traveled 4.3 inches.
Click to expand...
That's good information using high speed photography that JMB didn't have. I wonder how he cut things so close. I am sorry for doubting Tuner and I owe him an apology. But I am glad that we know have pictures and numbers to add to the thread as a result.

As a matter of curiousity, if you do the math on this, using 485.8 grams for the weight of a GI spec 1911, bullet mass of 230 grains, in the complete lack of a recoil spring or any friction, you get the bullet only moving 3.26" by the time the slide recoils 1/10th of an inch. This is way less margin than a G27, even. If we can rely on Tuner's 0.2" of travel before the lugs completely disengage, then we know the barrel starts tilting much sooner. Somewhere close to 1/10th an inch, maybe?

But we know, thanks to high speed photography of at least one particular gun and bullet, that the bullet is actually barely clearing the barrel when you figure in the rest of the factors. That's as expected, since 1911's work. To use Tuner's numbers we have 4.3" of bullet travel at the point the slide moves back 100 mics. But man, this is still cutting things closer than I would have guessed.

If you double the mass of the bullet and take a picture when the bullet is in the same place, about 1/10th inch after exiting the muzzle, where do you suppose the slide would be? How about if you lightened the slide+barrel by 50%? If you guess that the slide would be close to 2/10th of an inch back, then I would tend to agree.

Conversely, if you doubled the mass of the slide+barrel or halved the weight of the bullet, I would expect the slide to have moved roughly only 50 mics by the time the bullet just exits the barrel.

If you accept this, then you will see that any specific recoil-operated locked breech pistol can't shoot just any weight of a bullet without changing the relative lock timing. (Gas-operated or some other method would be different). If you do not accept this, I can probably show you why it's more or less correct. It's really simple physics. I would be happy to explain this in a simple way, even if there's a gang brewing that would rather call it arguing.
 
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No, please, go ahead and explain it.

(But please also explain why I would want to double the weight of the slide on a 1911).
 
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Returning to the vicinity where the OP's question was last seen, the one solution to his wife's difficulty in retracting the slide I'm aware of was S&W's little .35 S&W caliber autoloader. It's stiff recoil spring could be disconnected from the slide, so the the first round could be easily loaded. How that could be worked into a practical locked-breech mechanism I leave to someone else's ingenuity.
 
Ok, then. Here it is.

You are standing in the middle of a perfectly smooth sheet of frictionless material. You might imagine it to be like ice, but with 0% of the friction of ice. 100 feet away, there's an ice cream cone. You try to walk to it, but you can't do it. Your shoes just slip over the surface and you fall on your ass. You try to crawl, but it doesn't matter. Your hands and knees just slip over the surface. Essentially this is like being in outer space in a total vacuum. No matter how hard to you try to "swim" through outer space, you cannot propel yourself. But to keep things more simple let's stick with the magic ice.

So now, instead of being alone on this magic ice, you are standing next to your identical twin. You both weigh 200 lbs on the dot. You say to your brother, "Hey, Bro. Gimme a boost!"

"You got it, Bro," he replies. He pushes you towards the ice cream cone.

As you are propelled towards the ice cream cone, your brother screams.

"Whoa! I'm moving in the opposite direction. In fact, I am moving at exactly the same speed in the opposite direction!"

"Whoa, Bro. That's neat. Isn't physics cool?"

Now let's say you are stuck on the ice with 18 yr-old Gary Coleman. He only weighs 100 lbs. You ask Gary for a boost towards the ice cream, and he obliges.

"Whoa!" says Gary. "I pushed you, but I'm moving back!"

"Yeah, Gary. Don't worry. That's just physics. I just went through this with my brother."

"Watch choo talking bout, Willis!?"

"Um, Gary, my name is not Willis. What I'm talking about is conservation of momentum. Since we both started out with sum zero mass*velocity, we will retain sum zero mass*velocity after any interaction between the two of us, so long as we both retain our current mass. In fact, since I weigh twice as much as you do, you are now moving at twice the speed I am, in the exact opposite direction."

"Damn, Willis. Why you so smart? So what does this have to do with bullets and guns?"

"Well, Gary. If you made it this far and still don't understand, no worries. I can continue this story all day. Eventually something will sink in."
 
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Unless someone has a non-recoverable infirmity I think just about anyone old enough to safely fire a 1911 or any semiautomatic locked breach pistol can develop the ability to cycle a slide. Adding recoil buffers to reduce slide retraction force is the wrong direction to go; technique and strength training are the right directions.

Damn! I wish I had joined the party earlier when the frame battering dance began. I have seen a battered frame. It was an aluminum frame Beretta 84 .380 that had shot many max load 121 cast lead bullets. The only adverse affect was it was a little difficult to dismount the slide from the frame during disassembly. I have seen 1911s at the U.S. Army John F. Kennedy Special Warfare Center that have had countless thousands of rounds fired through them over decades by Special Forces students that did not have any frame battering. Some had worn pin holes that caused problems. I have seen cracked slides.
 
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... meanwhile some finite amount of time has passed...

"Oooh, here's the ice cream!" You reach out and grab the ice cream cone as you slide past. Success! Excited, you turn to tell Gary of your good fortune. But you realize that Gary is now 300 feet away from you and can't hear you. That's when your phone rings. You answer it with a timid, "Hello?"

"Yo, Willis! Did you get it?"

"Of course I did," you reply, coolly. You smile and look down at your ice cream cone. It's pistachio. Damn. You hate pistachio.... but you hold it up in triumph, with a flourish. Far in the distance, you can see Gary giving you the thumbs up. "Hey, how did you get my..."

"Well I been thinking, Willis," Gary interjects. "About this gun analogy. I think I figured it out."

"Oh? Well, ok. Shoot! No pun intended."

"Ok, Willis. Here it is. I am the bullet, and you are the slide. When we pushed each other, that was the cartridge combusting. The gases expanded and pushed us apart. Since I am half your weight, I moved twice as fast."

"That's right, Gary! By God you have it."

"Wait, there's more! The ice cream cone is the locking block. By the time you reach that ice cream cone 100 feet away, I have travelled 200 feet down the barrel."

"Yes - well, technically, you would have made it 300 feet down the barrel. Cuz I'm the barrel and I moved 100 feet, too. But yes, go on."

"But when your brother pushed you, he only made it 100 feet down the barrel by the time you reached the ice cream cone. Wait, I mean 200!" Gary beams at his realization.

"Yes, Gary, that is correct."

"So that means if the barrel were 250 feet long, I would have been 50 feet clear by the time you started eating icecream. But your brother would have still been 50 feet shy of the muzzle!"

"Yup. That's right. You deserve an ice cream cone. Do you like pistachio?"
 
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Nom de Forum said:
Unless someone has a non-recoverable infirmity I think just about anyone old enough to safely fire a 1911 or any semiautomatic locked breach pistol can develop the ability to cycle a slide. Adding recoil buffers to reduce slide retraction force is the wrong direction to go; technique and strength training are the right directions.

Damn! I wish I had joined the party earlier when the frame battering dance began. I have seen a battered frame. It was an aluminum frame Beretta 84 .380 that had shot many max load 121 cast lead bullets. The only adverse affect was it was a little difficult to dismount the slide from the frame during disassembly. I have seen 1911s at the U.S. Army John F. Kennedy Special Warfare Center that have countless thousands of rounds fired through them over decades by Special Forces students that did not have any frame battering. Some had worn pin holes that caused problems. I have seen cracked slides.
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The all too common permanent infirmity that makes slide retraction difficult is called diabetes. Loss of sensation in one hand is enough to make it very difficult to get a good enough grip to exert the necessary force, as my wife can attest. Good technique can help, but strength training is futile.

As far as frame battering, my S&W model 39 showed some galling on the top of the rails where the bottom of the barrel hood struck in recoil. The more serious failure was the crack that appeared extending downward from the slide stop hole. Apparently the rearward travel of the barrel was halted by the slide stop pin, and the frame wasn't up to the task. Since this was one of the first postwar autoloaders to use an alloy frame, it's not surprising the engineers didn't anticipate the effect of firing a lot of US and British WW2 surplus ammo through their pistol. I think it may have been a bit on the hot side...
 
For every action, there must be an equal and opposite reaction. But you are not accounting for all of the actions taking place.
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You can add all the other factor in there you want, but you cannot ignore conservation of momentum. If you care to add more factors that will offset a change in bullet mass, please enlighten me.

Not intended as an insult, just a hint.
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I suppose the broomstick was offered for sweeping the floor? Come, now. Don't play coy, darling. :)
 
Edarnold said:
The all too common permanent infirmity that makes slide retraction difficult is called diabetes. Loss of sensation in one hand is enough to make it very difficult to get a good enough grip to exert the necessary force, as my wife can attest. Good technique can help, but strength training is futile.

As far as frame battering, my S&W model 39 showed some galling on the top of the rails where the bottom of the barrel hood struck in recoil. The more serious failure was the crack that appeared extending downward from the slide stop hole. Apparently the rearward travel of the barrel was halted by the slide stop pin, and the frame wasn't up to the task. Since this was one of the first postwar autoloaders to use an alloy frame, it's not surprising the engineers didn't anticipate the effect of firing a lot of US and British WW2 surplus ammo through their pistol. I think it may have been a bit on the hot side...
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Please extend my sympathies to your wife. I completely understand as we have diabetes in my family. I purposely did not mention any specific non-recoverable infirmity because there are some many of them. I also have a family member with connective tissue disease that affects hand strength among other things. Some people who cannot cycle a slide by hand can do so by bracing the slides rear sight against an immovable object and pushing on the pistol grip. It is also possible to put a cocking handle on a slide that can be used to leverage the slide.
 
GLOOB,

I'm not ignoring conservation of momentum, I'm insisting on it being acknowledged.

The broomstick is Tuner's analogy. I'd rather let him explain it. But if you don't want to wait, he explains it here (read the whole thread).
 
Oh. And here I thought you were suggesting I go [deleted] myself with a broomstick. :)

Tuner has been through his broomstick analogy on the forums a year or two ago. I think he used a rope, though. Anyways, this theory proved highly controversial, and supporters and critics had lots of back and forth over this over many pages. Since I was involved, I am biased. That said, I think most people tended to agree that science and logic weren't close friends to this theory. But people have the right to believe what they want. I was and still am a critic.



.... and I can explain why, if you are curious! :)
 
GLOOB said:
.... and I can explain why, if you are curious!
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I thought you were going to explain it before but instead you launched into a '80s sitcom. I've seen an engineering analysis supporting the bullet drag theory. So please try for something a bit more along those lines.
 
"That's good information using high speed photography that JMB didn't have. I wonder how he cut things so close."
Math. Guarantee a lot of math was done to time the action. They had slide rules even back then, I believe.

I'd say it's also pretty self-evident that recoil-actions can only operate at a certain segment of the power continuum. I'm pretty sure a KPV would not cycle with a Beretta PX4 return spring even though the 14.5mm monster operates exactly the same way ;). The return spring seems to set the lower limit for loads that can be cycled (see Tuner's bit about how little force is actually needed to arrest a slide), while lug interfaces limit how high power levels can go (and hypothetical scenarios of a bullet having twice the mass of what could fit in the action and still have powder under it, while fun, are pointless; we could hypothetically moot the peening question by making the fantasy gun out of adamantium/mythril alloys)

In my extremely limited experience playing with recoil springs, I changed out a ridiculously worn out factory CZ52 spring with the heaviest Wolff offering. Initial firing of the gun was flawless, but I could actually perceive the slide returning to battery, a sort of secondary recoil that made reacquiring sights difficult. The new spring, in addition to being so stiff as to be impractical, has the only visible benefit of cycling the gun faster than I can notice --which is exactly what spring/mass/damper dynamics suggests happens when a system is stiffened with a stronger spring (it speeds up). Even ejection is the same as it was (though not when I'm running the 9mm barrel)

I said earlier than ejection may be harsher with a bad spring, but thinking about it, I think even that may be a stretch; I'll bet the ejection behavior is far more correlated with slide mass than buffer strength, since the slide still rebounds off the stops with authority to ensure better feeding reliability on the forward stroke. This same debate goes on all the time on gun building forums with regard to blowback actions; very many people really do believe a bolt which is initially subjected to thousands of pounds of bolt thrust cares about an extra 2lbs of spring weight at the beginning of the cycle when the case is pressurized.

TCB
 
If we can rely on Tuner's 0.2" of travel before the lugs completely disengage, then we know the barrel starts tilting much sooner. Somewhere close to 1/10th an inch, maybe?
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It's measurable.

The barrel drop begins almost immediately when you hand-cycle the gun because the geometry of the lower lug lets gravity pull it down as soon as the lug backs up on the slidestop pin.

It doesn't do that when the gun is fired.

(And here comes another 5-page argument, but here goes.)

The barrel engages vertically, but it locks horizontally with the barrel and slide lugs in opposition under high shearing forces...because the bullet exerts a forward drag on the barrel while the slide is pulling the barrel backward against that forward force.

This forward drag has been measured by the man who posted those pictures. It took 103 pounds of force to start the bullet into the rifling, and 93 pounds of steady force to get it to the muzzle.

This represents the strongest resistive/delaying force acting on the slide in the whole system. It explains why a locked breech pistol can be safely fired without a spring and it explains why the barrel can't unlock with a heavy-for-the-caliber bullet and high pressure can't cause the barrel to unlock early.

With the lugs locked horizontally in opposition under whatever pressure per square inch exists when the barrel starts to move backward...the barrel can't drop via gravity. It can't. Don't trust your observations while hand-cycling. It functions differently when the gun is fired.

The only analogy I can offer to demonstrate this is the a door.

Stand in front of a door that opens away from you and turn the knob. It turns easily.

Place your hand 2 feet above the knob and push with moderate force...and try to turn the knob. You'll notice that it's much more difficult, and...depending on a few factors...you may damage the mechanism if you force the knob to turn. The striker is forced against the striker plate...locked in opposition under shearing force and trying to get the striker to move is fruitless and possibly destructive. A 10 year-old child could stop you from opening that door.

So, even if a bullet and high pressures are present when the barrel reaches the linkdown point...which can't happen, even with a heavy bullet...

With the barrel lugs engaged horizontally under this shearing force at however many thousands of pounds psi exists when the link starts to pull...I strongly suspect that the link would fail before it disengaged them and allowed the breech to open, and the he lugs would almost certainly be damaged even if the link held and succeeded in pulling the barrel down.

The bullet drag/resistance/delay is something that few people stop to consider, or...even if they allude to it...insist that it's not a significant factor because of the high forces driving he system...but a hundred pounds of resistance is a hundred pounds of resistance no matter how you cut it. It trumps slide and barrel mass and all the resistance imposed by the springs combined.

And now, I gotta go get all these dogs out and prepare myself for the next wave of snark and condescension that these points will doubtless give rise to.

Regards
 
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