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Calculating rifle movement as bullet reaches muzzle

If you are really interested in physics, why not try a first level class in thermodynamics?
You sound ready for your first taste of entropy and enthalpy.
 
I know that more thinking is better than less. I wouldn’t want the world where Eve didn’t eat the apple. Don’t pick the blue pill. This site is sharpening the tip of the speer and as such everyone thinks they have already mastered basics considered so well settled, that exist all the way back in its shaft.

I’m with you on scratching deeper no matter who says there wasn’t an itch. No, the answer isn’t going to result in more X’s being shot. We are going to load and shoot guns the same way, regardless of the answer. I got resistance too, in 2021, but also a lot of deep thinking. Fugi, Region Rat, ebb, Jalenko and many others. These names still don’t make much sense to me by the way.

Without healthy verbal back and forth, nothing advances, muscles atrophy.

It does not matter who is the magnificent kite, who is the string pulling back, and who is the wind, without all three giving and taking, nothing takes flight. The critics are every bit in the right to push back, but if and when it’s right, they need to tip the hat.
 
You, as I have already mentioned, use the word “recoil” to encompass literally all, or nearly every generic motion there is,

Ok, I think it’s clear here that you have no idea where to find the ground…

What you quoted was very literally how I define recoil (like all scientific definitions for the word), which is not all “generic motion.”

You’re lost in weeds that you’ve planted. I’m sad for folks who might read your trolling in the future.
 
Ok, I think it’s clear here that you have no idea where to find the ground…

What you quoted was very literally how I define recoil (like all scientific definitions for the word), which is not all “generic motion.”

You’re lost in weeds that you’ve planted. I’m sad for folks who might read your trolling in the future.

… And when you said of the hypothetical, it’s not a rocket, we are not trying to create thrust, the cohesiveness of your reasoning collapsed.

When you accused me of a sin earlier than that, similar to here, while I still read your posts, I saw it for what it was, a distraction and deflection.

Recentering of the system is so relatively weak and easy to control, that when all guys dogmatically assuming that it could no sooner be stopped than the bullet that leaves the muzzle, as we can tell some people tend to think, and realize that’s not true at all, they may be very glad second thoughts were given the subject. But if not, tell me please, what did it do to them to have read it?

edit:

If generic recentering is what is going on Varmint Terror, then why even make the point of saying that “recoil” happens in the bore? Do we need to make the point as a matter of physics, that if we put our cheek on the stock, we push it down?

Do we need to write that if we pull back on the trigger, the gun might move? The same recentering that is on display and we are contemplating, would occur if the bullet took one hour to reach the muzzle. Do you disagree with that? That is not what I have in mind when I think of rifle recoil. Is this what you have in mind? Do you at least agree, recentering isn’t much force whatsoever, regardless of what else you think is added to it, which topic is very discussion worthy?

Has someone here insisted that they are right and you are wrong, or are they talking about concepts? I’d think you’d be more interested, not less, in recentering given the background you shared.
 
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From Vaughn's book in 1998. He went on to develop an "isolator" to dampen the transmission from the recoil lug to the stock, and measured the resulting benefit. You can google and download this book free of charge.
View attachment 1503664de
Lots of people bash on that book because there are a few things since that have proven wrong but the vast, vast majority of that book is solid gold, good info!
 
Since google is not as much in the business of providing answers as much as selling products and keywords, it’s surprising difficult to find something as simple as how far a rifle moves before the bullet leaves the barrel. Where I’m going with this is just adding a good, even if rough, value to the movement in discussions - rather than explaining to a kid the gun moves an amount that nobody knows, it would be awesome to be able to say in free recoil it might move .0xx” and with a good two handed hold and shoulder pressure that changes it .00x”.

Engineers among us will find this quite simple, so humor me

From memory of physics 101 years ago (feels like 101 years ago), I’m tending to think it would be a simple conservation of momentum? Roughly, if powder expands equally, would the distance of the center of mass of the powder be about half the barrel length, ignoring volume of cartridge case above and beyond the bore diameter?

mass(gun) x distance(gun) = mass(bullet) x distance(bullet) + mass(powder) x distance(powder)

My gut says that’s the easy part and describes the rifle in free recoil at the moment the bullet exits. Has anyone seen, or wish to take an educated guess, as to what kind of range a two-handed hunter hold combined with pressure from the shoulder adds to the mass of the rifle, reducing movement?

Somewhere, someone has high speed camera footage of free recoil and different holds as the bullet comes out, but I’ll bet it’s been dumbed down into an average fudge factor in an equation in a footnote of a ballistics book.

Thanks for your thoughts! This is one of those things that’s been in the back of my mind for decades and I wait for something to come up, but I was either busy and didn’t notice the conversation, or it was too vague to be of much help.
What could you possibly do with the info you seek?
 
I did not read all 10 pages, so if this has been mentioned, I apologize.
Ever try using the kinetic energy equation. KE= 0.5 x M x V(squared), where M is bullet mass and V is the muzzle velocity.
With the KE calculated, you can calculate in reverse what the velocity the rifle (Vrifle) is recoiling back: Vrifle = square root (2 x KE / Mass of rifle).
With the rifle recoil speed (Vrifle) known, you can calculate how much it travels back given a known time. Be consitent with your units throughout.
Just my 2cents
 
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Sweet baby Jesus I hope somebody can eventually produce any evidence or formula that applies to the moment the bullet is about to leave the barrel, and actually work the Quickload problem.

Almost 150 posts and it seems like a disagreement with basic physics, that nobody can back up.

I’m all ears from the first post until now.
Sweet baby Jesus buy your own gear and measure it yourself. It is not our job to bring you things on silver platters.

When you hang around engineers you will quickly understand that nothing worthwhile comes on platters - so while we try to help, at the end of the day, most of the time, the answer is yours alone to find. Especially if you want to know something very specific that few have cause to care about.

You say you're not the same person who asked the same question in the "Recoil" thread on RFC a couple of weeks ago, but you act just as nagging, whiny, and entitled. And the coincidence of the exact same topics, well, can't be calculated.

David
 
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I did not read all 10 pages, so if this has been mentioned, I apologize.
Ever try using the kinetic energy equation. KE= 0.5 x M x V(squared), where M is bullet mass and V is the muzzle velocity.
With the KE calculated, you can calculate in reverse what the velocity the rifle (Vrifle) is recoiling back: Vrifle = square root (2 x KE / Mass of rifle).
With the rifle recoil speed (Vrifle) known, you can calculate how much it travels back given a known time. Be consitent with your units throughout.
Just my 2cents
He was asking about movement of the gun's barrel during initial ignition and up to bullet exit.

Muzzle energy is calculated or given at the muzzle and doesn't account for the time from ignition to muzzle, so it doesn't translate into units of displacement. To integrate the velocity or displacement of the gun over the length of the barrel, we would need calculus.

I would have thought the simplified versions should make most folks happy, even if they are not very accurate, but then the swirl started.

I would have also thought that in 2023, with all the highspeed video on the internet, we would stop hearing all the mythology about how guns don't move till after the bullet is gone.... but it goes to show you I clearly over estimate the average bear.

Not to worry. In general the idea has come full circle... If you shoot a light weight gun with heavy recoil from a body supported position (or even benched), you better know how to shoot. Things start to happen before you even break the trigger. You don't need calculus or FORTRAN to figure that out....

Merry Christmas and Happy New Year!
 
You engineer guys have alway been a serious bunch. That building’s room’s lights were always on late night, weekends, you name it. Two cousins went engineer/Rice, very smart, not in danger of the back of their a$$ falling off from laughter, but verrrry smart.
 
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I take your meaning RR, the real thing, not weapons for entertainment, as we discuss and use them, mainly.
 
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What could you possibly do with the info you seek?
Who is the shooting world isn‘t curious about how far a rifle can recoil before the bullet exits? If a rifle only moves 1/32”, that’s much different from one that moves 1/4”. Even as a teenager I’ve wondered this.
 
Sweet baby Jesus buy your own gear and measure it yourself. It is not our job to bring you things on silver platters.

When you hang around engineers you will quickly understand that nothing worthwhile comes on platters - so while we try to help, at the end of the day, most of the time, the answer is yours alone to find. Especially if you want to know something very specific that few have cause to care about.

You say you're not the same person who asked the same question in the "Recoil" thread on RFC a couple of weeks ago, but you act just as nagging, whiny, and entitled. And the coincidence of the exact same topics, well, can't be calculated.

David
I find it funny that two people ask the same question, that no engineer wants to touch as a center of mass calculation, and that makes me …”nagging, whiny, and entitled.” As I said earlier, my thick skin doesn’t even register name calling, so call me whatever makes you feel better.

I simply asked the question. The responses have been mostly like yours, dismissive, condensing, accusatory, and have gone off in tangents about energy, velocity, acceleration, and in the end have said we can’t calculate displacement of the rifle. It’s also been quite interesting how many have said this is a measurement nobody is interested in, which is silly.

I began this with the question of how to calculate the displacement, open to anyone and everyone who has a better grasp of the physics, but it soon became obvious there is blind spot with basic physics and which principles apply and which don’t. The principle of a constant center of gravity, call it a conservation of center of gravity if you like, has been rejected across the board for this closed system. It’s a kind of defensiveness I’d think more common with religion or politics.

Nobody who understands, or believes in, simple balancing of masses and displacements, wants to speak up and be poo pooed by other engineers. I don’t blame them - there is no upside for them. There is no upside for me, but I started the thread and find I’m a good judge of common sense, and am still waiting for anyone with an understanding of basic physics to explain why balancing of masses and displacements doesn’t work. When someone says it doesn’t work because of ______ I’m all ears, but simply throwing in thermodynamics isn’t convincing - one of the principles in thermodynamics is mass isn’t created or destroyed in a closed system. Throwing in uneven acceleration isnt convincing because the internal force causing the acceleration has a proportional effect on the two objects moving away from each other.

This has probably reached the best and brightest who wished to contribute, with nearly 200 posts, and unfortunately there is no consensus on how easily the question can be solved. However, just in the elementary searches done since the first post, nothing at all has surfaced discounting my approach, but maybe 50 lectures and basic physics experiments from two dozen universities seem to confirm it.
 
And if nobody came here and ask questions then nobody could come here and give their $0.02 worth So ask away I get more enjoyment reading the replies than the question, just my $0.02 for what it’s worth
 
Are not Internal and External ballistics aspects to Shooting? And aspects that many people here discuss?
Can say, I have on several occasions over the years here with in the forums.
Are you saying that recoil is considered part of "internal or external ballistics"?

Internal is everything that happens between ignition and the bullet leaving the muzzle.

External is everything the bullet does AFTER it leaves the muzzle.

Recoil is....well...recoil. It has nothing to do with either.

But I do agree.....it has EVERTHING to do with precision shooting...even with machine rests.

Tod
 

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