Roles of Springs in Recoil and Feeding of the 1911 Government

[MachIVshooter]

You would have spared yourself a lot of flak if you'd started off by saying it's a personal hypothesis of yours rather than with a loquacious & authoritarian OP.

You're also off on some tangent now that has nothing to do with normal Browning tilt barrel operation, but rather speculating about hearsay of occurrences with non-standard guns and attempting to correlate it with the former, and overcomplicating a simple sequence of events in the process.

 

[RX-79G]

Joshua,

I don't know what your last post has to do with previous posts. Squibs can and should cause a 1911 to cycle, because it provides a force to recoil from.

The slide and barrel are a unit. After pressure has dropped they arrive at a point where their paths diverge, and they do with no stress between them. The barrel was along for the ride, and then in jumps off. It can't "overtake" the slide that it was a passenger on, and it parts company with the slide when they are going the same velocity. There are no other important forces at work.

What is confusing about that for you?

 

[Joshua M. Smith]

Hello,

It's not confusing, though I've made it sound that way.

The slide is being slowed by springs. The barrel is not.

If the slide were slowed enough in that 1/4", it seems like the force on the barrel's upper lugs should shift to the rear of those lugs, kinda like a trailer hitch when you brake the towing vehicle.

I just don't know if 1/4" is far enough to do this.

The OP started as an answer to a new 1911 owner who wanted to swap everything and had confused himself by trying it all at once.

I tried to simplify the operations to something he could easily imagine. I also had him order Kalhunsen (sp?)

This was never supposed to be an authoritative piece. I amplified the spring's roles to make a point to him. That's why the opening paragraph says what it does.

Regards,

Josh

 

[RX-79G]

I just don't know if 1/4" is far enough to do this.

It isn't, and it doesn't matter. Very slight deceleration is not enough force to make any significant friction between the two. The recoil and mainspring deceleration is so small at this point that there is no muzzle rise as those springs feed back into the frame.

 

[Walt Sherrill]

The slide is being slowed by springs. The barrel is not.

The slide and barrel are BOTH slowed by springs UNTIL the barrel has fully disconnected from the slide, but...

As others have noted, the recoil and main springs are really there to power other functions (like charging the hammer spring or chambering of the next round); the slowing of the slide is a benefit but not an objective -- and that role is almost inconsequential in terms of how it affects (and diminishes) recoil.

The recoil spring CAN change the recoil experience, and help the shooter better manage different loads, but it's not really there to protect the gun or the shooter. (If I remember correctly, JMB didn't call that spring the "recoil" spring. That was a later usage.)

The 1911 and most other semi-autos would still fire properly if the recoil spring wasn't installed; the barrel and slide would still separate and decelerate and stop (due to a loss of powering pressure and the presence of abutments and stops or links). If you could manually cock (or convert the gun to a DAO function), you wouldn't even need the slide to charge the hammer spring/main spring. You'd just have to manually chamber the next round...

 

[entropy]

I didn't; never heard of the feller. I was raised by an engineer father who taught me a lot; could be that.

I'll look into this Peter G. Kokalis. Sounds like someone I may like to read. What does he write? (I won't have time til later to look him up.) What of his do you recommend?

Regards,

Josh

He writes for Firearms News, what used to be Shotgun News. His writing style is very technical, which is why I like it. It can be self-aggrandizing also, (which yours isn't, thankfully) and since he got old he puts pictures of his toy boys or whatever in the articles, instead of himself, as he used to. Look up back issues of Shotgun News; he writes about a different gun every issue, then goes on about how he fixed them for the Salvadorians, (or whatever group might have used that gun). OK so it's obvious I don't like that part of his writing, but if you want to know exactly what goes on every millisecond during any gun's firing cycle, he's probably written about, and you won't find better technical gun writing.

Naw, I'd be afraid of the SKS, too, and those things slamfire much more than those other designs. In fact, it's fairly common if you don't use military primers in the SKS.

If it's designed without a firing pin spring, then it's safe for the ammo specified.

Josh

Seen that a few times, always amusing when one runs through the mag....

 

[Coltdriver]

I hate to say this but for the unwary this post is a classic example of don't believe everything you read on the internet.

I think 1911Tuner would be able to clarify a lot of what is incorrect on the OP.

 

[RX-79G]

I think 1911Tuner would be able to clarify a lot of what is incorrect on the OP.

Except that 1911tuner would add his own erroneous claims about 1911s being blowback, carrying at half cock, not needing a link, etc.

 

[Varminterror]

I always hate seeing threads on 1911 FP's...

"Inertia" inevitably ends up getting mis-used over and over and over...

There is no such thing as "forward inertia," as inertia is a property of an object with NO velocity in the considered direction. Inertia is that part of Newton's law where "an object at rest will remain at rest unless acted upon by a force." Momentum is the other part of the law where an object in motion will remain in motion unless acted upon by a force.

 

[MachIVshooter]

I always hate seeing threads on 1911 FP's...

"Inertia" inevitably ends up getting mis-used over and over and over...

There is no such thing as "forward inertia," as inertia is a property of an object with NO velocity in the considered direction. Inertia is that part of Newton's law where "an object at rest will remain at rest unless acted upon by a force." Momentum is the other part of the law where an object in motion will remain in motion unless acted upon by a force.

While I agree that they are not interchangeable and often misused terms, that's not exactly correct:

Inertia: property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force.

Simply put, inertia exists as a product of mass, while momentum is dependent on mass & velocity; momentum is KE.

A bit more precise explanation:

Inertia is an intrinsic characteristic of the object related to its mass. Inertia tells you how much force it will take to cause a particular acceleration on the object.


Momentum is a function of an object's mass and velocity. Momentum is a measure of the kinetic energy of the object.


A massive object can have any momentum (at least as long as its velocity is less than light speed) including zero or negative momentum depending on the reference frame and coordinate conventions, but always has positive nonzero inertia.

So, in the context of this conversation, the slide & barrel assembly has inertia, and it develops momentum. The inertia exists even when momentum is zero because they are static, while the momentum us generated, and changes not only in quantity, but in vector. Both are factor in design. The recoil energy needs to be enough to overcome the inertia of the static slide, and the recoil spring needs to counter it's momentum to a degree and then overcome the same inertia to return it to battery.

Of course, it's more complicated than just those calculations, since you have friction & friction coefficients to deal with, as well as making sure the combined spring force and slide momentum are enough to strip & chamber a cartridge.

 

[Varminterror]

Inertia is the resistance to change in movement - there are only two implied directions applicable for a firing pin. Inertia is effectively what retracts the firing pin when the slide starts to move forward and the pin does not, but that's about the only instance where "inertial firing pin" applies.

Hammer hits it, it flies forward freely and has enough MOMENTUM to activate the primer... That's not inertia.

 

[MachIVshooter]

Inertia is the resistance to change in movement - there are only two implied directions applicable for a firing pin. Inertia is effectively what retracts the firing pin when the slide starts to move forward and the pin does not, but that's about the only instance where "inertial firing pin" applies.

Hammer hits it, it flies forward freely and has enough MOMENTUM to activate the primer... That's not inertia.

When static, the firing pin has no momentum, just inertia.

Once set in motion, it has both. But it has inertia on all axis, with momentum only on a single plane. However, the inertia in the same vector as the positive momentum is greater than the inertia on other planes, since it will take more force to accelerate the object in motion in the opposite direction as it would to continue accelerating it in that direction or accelerate it on another plane. In that sense, a firing pin spring does act to counter both the momentum and the inertia of the firing pin when the slide returns to battery.

This is why some designs must have a firing pin spring, because the inertia and momentum of the firing pin may exceed the resistance of the primer cup when the bolt or slide returns to battery. In this physical context, they are not the same, but are inseparable.

 

[RX-79G]

Inertial firing pins have springs so they stick far enough out to get smacked by the hammer. If it didn't have a spring it could end up too far forward and not sufficiently accelerated by the hammer. Full length firing pins don't need springs to prevent slam fires, but some have them to keep the pin head from interfering with the case rim. Full length firing pins have just as much mass and potential momentum as inertial pins. The spring is for primary function in locating the pin for firing. Any other benefit is conjecture.

Inertial: (of a frame of reference) in which bodies continue at rest or in uniform straight motion unless acted on by a force.

I don't see how "inertial" would not be the most accurate term. "Momental" is a word, but not really in common use. The point of the term is to indicate that the firing pin is not mechanically slaved to the firing components, but works by continuing to move in the direction it started in. "Momental" would suggest that the degree of energy it is carrying is high, like the way "speedy" indicates a large amount of speed. That would be more confusing than simply referring to its motion without reference to energy.

 

[Joshua M. Smith]

I hate to say this but for the unwary this post is a classic example of don't believe everything you read on the internet.

I think 1911Tuner would be able to clarify a lot of what is incorrect on the OP.

I actually found Tuner and have been talking to him about this post.

Before I stopped focusing on the 1911 the first time around, he and I used to talk a lot on these boards. I really enjoyed discussing theories with him because he likely tested whatever hypothesis I'd formed.

After I got back into 1911s, he was nowhere to be found. I suspect he got tired of the fighting, but I've not asked him.

I did find where he's hanging out, though, by pure accident. This same post has been the point of several interesting discussions.

Stephen A. Camp for BHP and Tuner for 1911, I think.

Josh

 

[RX-79G]

I suspect he got tired of the fighting, but I've not asked him.

I suspect he got tired of people pointing out when he was flat out wrong and that didn't fit with his self-appointed titles as guru of the 1911 and handgun physics super quizmaster.

There is nothing (accurate) Tuner has to say that you can't find in a good shop manual, which might be why you will find him many places, just not on the 1911forum. But he is a master of self promotion.

 

[Walt Sherrill]

There is nothing (accurate) Tuner has to say that you can't find in a good shop manual...

That's probably true of ANYONE who makes accurate comments about 1911s (or other guns) on this forum.

But he is a master of self promotion.

I've not seen 1911Tuner promoting himself all that much -- unless you consider posting on forums like this "self-promotion." But, then, you and I do that, too.

I have visited him at his home, talked guns with him, and saw no evidence of an inflated ego or any form of self-aggrandizement. The only promotion I've seen coming from him has to do with him finding homes for abandoned and rescued dogs.

On the other hand, I have seen a number of folks get downright nasty when they disagree with some of the things he's written, sometimes resorting to ad hominem attacks rather than pointing out HOW or WHY 1911Tuner's technical advice or guidance might be wrong. On forums like this, that's pretty common.

 

[RX-79G]

1911tuner is Mr. Ad Hominem when backed into a corner by his own assertions. Maybe he's mellowed from when he first showed up on TFL, but he certainly is not above name calling.

The self promotion I refer to is simply showing up on a forum, labeling yourself something like "AR15mastersmith" and then presenting every suggestion as having arrived from countless years of building and testing under unusual circumstances, all while defaming Kuhnhausen at every turn about one point that was edited out of his books decades ago. Confident arrogance and actually re-checking the manual before posting will make anyone with a reasonable firearms knowledge appear to be a font compared to your average forum Joe. But talking down to people, debasing them and throwing accomplished authors under the bus to maintain the appearance of authority is absolutely self promotion.

He's a really nice guy, as long as you treat him like the expert he believes he is. The moment that veneer cracks things shift. Maybe that's what happens when you've filled a knowledge void so long - you start believing the praise means you are a different class of forum member.

 

[Joshua M. Smith]

Good lord, man, I've filled a knowledge void regarding the Mosin-Nagant and enjoy helping others with that rifle. So many have misconceptions about it that it's not funny.

I see Tuner as the same type. He knows a lot about the 1911, enjoys thinking and postulating theories, and helping people out.

Josh

 

[Delmar]

If you make your time interval small enough, any impact can be seen to "stick" before an object starts moving in the opposite direction as the objects deform. The slide and frame actually deform momentarily upon impact. As long as this impact remains in the elastic range, the materials will return to their original shape. If the impact exceeds the yield strength of the material, it will not return to it's original shape. Thus frame peening and the popularity of slide buffers for some 1911's.

Any time an object's velocity vector changes direction by 180 degrees, at some point it's velocity must be zero. No way to go from negative to positive without crossing zero. This small amount of time when the slide velocity is zero, as the slide and frame are deformed then return to shape as the slide velocity vector changes direction, is what Joshua M. Smith is calling the "momentary pause".

For example, if we define the bullet movement direction (towards the muzzle) to be the positive direction on a 1911, then the slide is moving at about negative 25 feet/sec when it impacts the frame. At some point this negative velocity (towards the back) must go to zero, and the recoil spring must start accelerating the slide in the positive direction for the slide to move forward and close. Again, no way to go from negative to positive without crossing zero.

Many people consider something with a velocity of zero (no matter how small the time interval) to be "paused".

Another term for this is momentum.