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How much power does the action consume
- Thread starter Mallard
- Start date
You can't lose energy in Newtonian terms, but a gun that recoils more (even with a closed bolt) will deliver less energy to the target.
Look at it this way... Let's say we set up a chrono on the side of 495. You fire a shot through the chrono while we're standing 15 feet away and record the result. Then we hop into my car, go down one exit, turn around and I drive at 120mph toward the chrono. You're standing up hanging out of the sunroof and you fire another shot through the chrono right after we pass it. You were 'recoiling' away from the chrono at 172 FPS, so the second round will deliver that much less energy to the target.
I agree with everything you've said; I think you're reading statements that aren't there. I'm just not idealizing everything. Will not the semiautomatic action will have energy lost to internal friction? Your equivalently massed single shot will not suffer these internal inefficiencies.
You just asserted, correctly, that a rifle on a spring will eject a projectile a few FPS slower. I'm agreeing with that. A spring-tensioned slide is a rifle on a spring. EDIT: + heat.
EDIT: The internal heat isn't really the issue, although I seem to like saying that for some reason. It's the rifle on the spring. That's exactly what we're saying, although I didn't get it when you first posted it.
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strangenh
NES Member
True but only because we already are moving at that relative velocity. However, the barrel of a SA pistol is moving no more than the barrel of a bolt before the bullet is already separated from the system. I do agree that a bullet shot from a recoiling gun (my gun suspended from a spring) will lose some velocity as the barrel, moving back as the bullet moves forward, DRAGS on the bullet and as the system as a whole moves backwards.
In a straight blowback, I would agree that once the bolt is in motion, it can rob the system of energy as the gas pressure drops before the bullet leaves the barrel. That is a different issue.
Internal friction will strip energy only once the friction happens. In a straight blowback, perhaps. In a locked action, no, and that's part of the point. The rifling type probably matters lots more than some imagined transfer of energy into heat instead of momentum.
No it isn't, because the spring doesn't move until after the system separates.
I've spent a good deal of this thread arguing this isn't true. I claim the barrel and slide begins to move rearward immediately.
EDIT: This seems to be the key to the disagreement, as I can't find fault with anything else you've said.
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strangenh
NES Member
No worries and I agree we're discussing the edges of it at this point. It always boils down to the facts on the ground, doesn't it? I'd be even more interested in the effect of rifling on velocity and the formulas to determine the effect on velocity of the rifle suspended on a spring, given a certain friction/drag coefficient in the barrel.
![[devil]](/xen/styles/default/xenforo/smilies.vb/015.gif "Devil [devil]")
strangenh
NES Member
Why reality is hard:
http://www.ballisticsbytheinch.com/9mmluger.html
Look at the results. The top table shows a fixed barrel, single shot, locked breech shot (T/C Contender). The lower table shows the results from other "real" firearms. Look at the Kel-Tec and Beretta CX4 Storm. Both of those are straight blowback 16" barrel guns. Compare with the single shot 16".
I think it helps illustrate that the effect of the action - even a blowback action - is ephemeral compared to other factors like rifling and chamber type.
http://www.ballisticsbytheinch.com/9mmluger.html
Look at the results. The top table shows a fixed barrel, single shot, locked breech shot (T/C Contender). The lower table shows the results from other "real" firearms. Look at the Kel-Tec and Beretta CX4 Storm. Both of those are straight blowback 16" barrel guns. Compare with the single shot 16".
I think it helps illustrate that the effect of the action - even a blowback action - is ephemeral compared to other factors like rifling and chamber type.
What I find interesting there is the fact that the 18" barreled MP5 clone has lower values (for the most part) than the 2 16" guns. No compromise, eh?
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The energy is not wasted if the bean themselves in the head...
smokey-seven
NES Member
Thanks to all posters here and to the OP, good job, any thread that gets the blood going like this one has, is a good one. I think we all heard some interesting viewpoints, many incorrect and many correct.
For my reply, I did some basic thinking and thought it needed saying. We need a couple identical examples. Since I loved the slide / barrel lock, unlock and the barrel does not move until the bullet is gone, lets pick a 1911A1 for one gun and another identical 1911A1 for the other.
We will weld up the barrel and slide to the frame and remove enough metal so that the mass is equal between the two, to 1/1000 of a gram. We will now insert 2 identical super anal overly engineered duplicate loads into each gun. (I'm still trying to figure out how to load the welded one, but lets say Merlin got it loaded.)
We will now attach our newly invented recoil measurement device that will also fire our two weapons.
Here I will quote HooVooLoo
He's right.
But we still need our test firing. The OP suspected that the Semi Auto would penetrate less than a bolt action and provided his observance that would appear to back that up. I disagree that you can test two different weapons with the same load and call one that has less performance on the type of action. Thus my 2 same pistols but one is fixed and the other has a working slide.
Lets pick a barrel length of 4 inches from the front of the loaded bullet face to the muzzle for easy figuring.
Lets say the muzzle velocity is 900 Ft/Sec
Doing the math, and given that the acceleration is constant from projectile start to leaving the muzzle, the average velocity in the barrel is 450 ft/sec.
The barrel is .3333 feet long and the time in the pipe is .3333 feet / 450 feet/second for a total flight time down the pipe of approximately .0007 seconds.
So, we have expended 100% of the total force on the action of the weapon in .0007 seconds.
We have all the bases covered here, the end result will show that our recoil meter records recoil in the fixed slide higher than the operable slide. What has happened is that the force towards the rear has been lessened by virtue of mass being moved a distance over a period of time.
bolt face here <--------- explosion here ---------> bullet leaves muzzle here
Statement 1. The force is equal in all directions.
Statement 2. The recoil is higher in the fixed weapon.
Statement 3. In the functioning slide, the bullet has left the barrel before the barrel and slide have unlocked, BUT the barrel and slide start rearward as soon as the mass of all moving parts and spring tension has been over ridden by the pressure of the explosion.
Statement 4. As I recall, SAMMI pressure for the 45ACP is around 20,000 PSI. So roughly a little less than 1/2 of that (square inches of cartridge base) has hit as force on the face of the bolt and transferred to the slide over the time of 0 to .0007 seconds.
Now my opinion should you choose to take it or leave it, is that if you lined up phone books and shot 10 rounds each, out of our two test pistols and hit the phone books at the same perfect place for all ten shots, you would have a hard time determining which page the bullets stopped on and there would be so little difference between the two that it made this whole test almost pointless.
It has been a lively discussion tho.
For my reply, I did some basic thinking and thought it needed saying. We need a couple identical examples. Since I loved the slide / barrel lock, unlock and the barrel does not move until the bullet is gone, lets pick a 1911A1 for one gun and another identical 1911A1 for the other.
We will weld up the barrel and slide to the frame and remove enough metal so that the mass is equal between the two, to 1/1000 of a gram. We will now insert 2 identical super anal overly engineered duplicate loads into each gun. (I'm still trying to figure out how to load the welded one, but lets say Merlin got it loaded.)
We will now attach our newly invented recoil measurement device that will also fire our two weapons.
Here I will quote HooVooLoo
He's right.
But we still need our test firing. The OP suspected that the Semi Auto would penetrate less than a bolt action and provided his observance that would appear to back that up. I disagree that you can test two different weapons with the same load and call one that has less performance on the type of action. Thus my 2 same pistols but one is fixed and the other has a working slide.
Lets pick a barrel length of 4 inches from the front of the loaded bullet face to the muzzle for easy figuring.
Lets say the muzzle velocity is 900 Ft/Sec
Doing the math, and given that the acceleration is constant from projectile start to leaving the muzzle, the average velocity in the barrel is 450 ft/sec.
The barrel is .3333 feet long and the time in the pipe is .3333 feet / 450 feet/second for a total flight time down the pipe of approximately .0007 seconds.
So, we have expended 100% of the total force on the action of the weapon in .0007 seconds.
We have all the bases covered here, the end result will show that our recoil meter records recoil in the fixed slide higher than the operable slide. What has happened is that the force towards the rear has been lessened by virtue of mass being moved a distance over a period of time.
bolt face here <--------- explosion here ---------> bullet leaves muzzle here
Statement 1. The force is equal in all directions.
Statement 2. The recoil is higher in the fixed weapon.
Statement 3. In the functioning slide, the bullet has left the barrel before the barrel and slide have unlocked, BUT the barrel and slide start rearward as soon as the mass of all moving parts and spring tension has been over ridden by the pressure of the explosion.
Statement 4. As I recall, SAMMI pressure for the 45ACP is around 20,000 PSI. So roughly a little less than 1/2 of that (square inches of cartridge base) has hit as force on the face of the bolt and transferred to the slide over the time of 0 to .0007 seconds.
Now my opinion should you choose to take it or leave it, is that if you lined up phone books and shot 10 rounds each, out of our two test pistols and hit the phone books at the same perfect place for all ten shots, you would have a hard time determining which page the bullets stopped on and there would be so little difference between the two that it made this whole test almost pointless.
It has been a lively discussion tho.
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I'm very late to the party here, but this has been an interesting discussion and I think smokey-seven has basically got it. We all know the energy to operate the action on a mechanical semi-auto (different discussion for the gas-operated ones) has to come from somewhere. Most of the discussion centered on how that energy was taken from the projectile, but ignored the fact that the same energy imparted to the projectile is also imparted (in the opposite direction) to the firearm and perceived by the shooter as recoil. That's where the energy to operate the action is being taken (borrowed might be a better term) from, which is consistent with the conventional wisdom that semi-autos have a softer recoil than fixed breech guns.
If I'm understanding Smokey correctly, he's suggesting that the force used to cycle the action actually depends on the reactive force applied to the frame when the gun recoils.
Which makes sense. If you imagine a gun fired with a totally limp wrist (no resistance on the frame at all), a semi-auto and a locked breech should recoil identically, and the semi-auto's action would not cycle.
Not sure what that proves about where the energy's coming from though.
Which makes sense. If you imagine a gun fired with a totally limp wrist (no resistance on the frame at all), a semi-auto and a locked breech should recoil identically, and the semi-auto's action would not cycle.
Not sure what that proves about where the energy's coming from though.
What it proves should be that no matter the action, the firearm will eat up the same amount of energy from the cartridge. With a locked breech, it will recoil more. With a semi-auto, the firearm as a whole will recoil less, but the slide/bolt/etc will move.
smokey-seven
NES Member
Epiphany
The brilliancy of J. M. Browning was to understand that the recoil in itself was a usable (and prior to this, "wasted") force and could be taken as a byproduct of the workings of the projectile and, "reused or converted" into working forces to operate a semi or full auto weapon. That is a simplicity in design that is rarely duplicated. It's an epiphany!
I do not care if it's a prototype pre-1900 Browning or other pistol, they use the basic principle of recoiling action to operate the mechanism. Good old boy John did the math, made the guns and he did just fine in his calculations as well as his design.
I will forever stand in awe.
The brilliancy of J. M. Browning was to understand that the recoil in itself was a usable (and prior to this, "wasted") force and could be taken as a byproduct of the workings of the projectile and, "reused or converted" into working forces to operate a semi or full auto weapon. That is a simplicity in design that is rarely duplicated. It's an epiphany!
I do not care if it's a prototype pre-1900 Browning or other pistol, they use the basic principle of recoiling action to operate the mechanism. Good old boy John did the math, made the guns and he did just fine in his calculations as well as his design.
I will forever stand in awe.
smokey-seven
NES Member
Continuing....
No, it is acting on the barrel/slide and THEN the receiver (frame). It's an over time thing.
Forget the limp wrist, move into a suspended weapon, one welded and one slide functional. The total forces applied rearward are the same (if the weapon mass and the ballistics are the same) so the only difference is in the TIME of the reaction (read recoil over (whatever.FGBHIK seconds). I would agree that the total force in recoil is identical, given matched masses and forces. The only difference is in time of force over the duration of recoil.
My premise? Recoil is reduced in a functional slide action device and it imparts VERY LITTLE reduction in projectile explosion forces. Recoil is increased in a fixed action and imparts VERY LITTLE INCREASE in foot pounds of energy imparted to the projectile.
Look at the mass of the complete slide + components. Look at the forces of the (give a mass... 230 grain? approx 20,000 psi) projectile leaving the barrel at approx 900fps. Do the math for an approx 450 fps average and driving the slide aft for the distance and mass involved is minuscule in the scheme of things. I am guessing X pages of phone book difference at 20 feet. I got phone books. This is still an absurd roughly 10 pages of book penetration discussion. Lets get the Box of Truth involved?
No, it is acting on the barrel/slide and THEN the receiver (frame). It's an over time thing.
Forget the limp wrist, move into a suspended weapon, one welded and one slide functional. The total forces applied rearward are the same (if the weapon mass and the ballistics are the same) so the only difference is in the TIME of the reaction (read recoil over (whatever.FGBHIK seconds). I would agree that the total force in recoil is identical, given matched masses and forces. The only difference is in time of force over the duration of recoil.
My premise? Recoil is reduced in a functional slide action device and it imparts VERY LITTLE reduction in projectile explosion forces. Recoil is increased in a fixed action and imparts VERY LITTLE INCREASE in foot pounds of energy imparted to the projectile.
Look at the mass of the complete slide + components. Look at the forces of the (give a mass... 230 grain? approx 20,000 psi) projectile leaving the barrel at approx 900fps. Do the math for an approx 450 fps average and driving the slide aft for the distance and mass involved is minuscule in the scheme of things. I am guessing X pages of phone book difference at 20 feet. I got phone books. This is still an absurd roughly 10 pages of book penetration discussion. Lets get the Box of Truth involved?
My point here, though, is that without some resistance force acting on the frame, the welded and functional slides should behave identically. To cycle the action, the slide has to be moved relative to the barrel. That requires that the net force on the slide must be different from the net force on the barrel by enough to overcome static friction, as well as any structure (springs or welds) that connect the slide to the frame.
strangenh
NES Member
Right. The firearm is going to experience the force as a matter of basic physics. It can't happen any other way. So, JMB redirects some of it into the action. Not "from" the round, but "from" the rest of the recoiling firearm. The true brilliance is in keeping the action locked up until the round departs so there is no change in the gas pressure, then letting stuff fly free.
THIS
Very late to this thread, so I'm sure this has already been said. An example- notice the difference in felt recoil between a semi-auto 12 GA shotgun and a pump or bolt action.
I don't think this is correct. This is what Hooke's Law is about. Even suspended in a vacuum, the recoil spring will compress. The spring will temporarily store the energy and apply force relative to its displacement. You could conceivably engineer a gun that would cycle floating in space by tampering with the mass of the slide, frame, and spring constant.
Why would the spring compress instead of simply moving? The reason the spring normally compresses instead of moving is because it encounters resistance to moving.
Actually, you're correct (now that I think about it more), but the spring would only compress until the force needed to compress the spring was less than the force needed to accelerate the frame to the same speed as the slide.
Exactly. If you make the mass of the frame sufficiently large relative to the slide and strength of the spring then the gun still cycles. The frame, with no friction to hold it in place, moves back also, just not far enough to render the movement of the slide ineffective. The real-world problem is that the frame would have to be so large as to render the firearm impractical, which is why for firearms of practical size we need to add the mass of our own body to that of the frame when we fire the gun.
Exactly. If you were to draw free-body-diagrams, the trick would be that force on one side of the spring is not always equal to the force on the other side of the spring. I think the accelerations will be different relative to the quantity (force applied/mass-of-frame) but I haven't fact-checked that.
I've more or less given up on the original topic, and am mostly just sniping at physics nitpicked when I can
![[wink]](/xen/styles/default/xenforo/smilies.vb/002.gif "Wink [wink]")
.I'd bet there are trick guns, (like maybe really cheapo .22s or tricked-out Open guns) that would cycle suspended in space. But I'm not basing that on any actual facts.
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I've more or less given up on the original topic, and am mostly just sniping at physics nitpicked when I can
We left the OT behind a while ago, but as long as it keeps being interesting, I'm still in.
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Arguing on the internet at it's finest. Here is my contribution to this guilty pleasure.
It's not some magical recoil capturing device that makes it work per se, though you are capturing energy diverted backwards which is technically recoil.
OK, so lets use the 1911 example. How is it working? My understanding is this.
Those serrations on the top of the barrel and under the slide lock up and unlock very easy when the barrel can move back and forth on it's pivot because the barrel is free to move on it's pivot link (that part of the barrel which connects it to the frame). 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. 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. Once the bullet is out and the pressure on the barrel to go forward is begins to wane, the barrel is now free to pivot on it's barrel link pivot. The slide is then able to swing back and the cycle begins to occur. ie; the rearward movement of the slide overcomes the forward force of the barrel.
The key to making this work is to have enough weight in the slide plus spring tension to require a certain minimum amount force needed to cycle it (too much and it won't cycle, not enough weight/spring tension and the lock won't work). 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. So lets put this in ft lbs. Using completely made up numbers. The lockup works at 100 ft lbs of force on the barrel going forward but releases at 75 ft lbs. 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. This releases the lock on the barrel. Let's say that there is still 10,000 PSI of pressure still in the barrel at this point. That is what is used to cycle the slide backwards by way of the pressure put on the casing and the barrel. See this video at sec 45. http://www.youtube.com/watch?v=l5PHkv3f-9U You will see a small pressure wave come out of the ejection port, though most of the pressure is relieved out of the front of the barrel, the slide attains enough backwards inertia to cycle.
This is where the slide weight and spring tension comes in. There is a time where the pressure on the barrel is not strong enough (someone mentioned it earlier) to keep the lock engaged. That requires that there is enough inertia* in the slide to allow the pressure to build in the chamber before the slide cycles. If it cycles before the lock is engaged, the lock never engages and the barrel will rise as the bullet is in the chamber. Too much weight and spring tension and the slide can't move back fast and far enough and you exhaust all of the pressure out of the front of the gun without capturing enough for the slide recoil. All of this happens in such small fragments in time that you need a 1200 fps camera or better to catch the action.
To summarize, in very simple terms, the forward pressure on the barrel keeps the slide locked until that forward pressure is relieved (which can't happen until the bullet leaves the barrel). Once it is relieved, the barrel can move backwards allowing the slide to cycle. That's how the locking mechanism works.
* remember relativity, everything has inertia including things at rest or the resistance of any physical object to a change in its state of motion
It's not some magical recoil capturing device that makes it work per se, though you are capturing energy diverted backwards which is technically recoil.
OK, so lets use the 1911 example. How is it working? My understanding is this.
Those serrations on the top of the barrel and under the slide lock up and unlock very easy when the barrel can move back and forth on it's pivot because the barrel is free to move on it's pivot link (that part of the barrel which connects it to the frame). 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. 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. Once the bullet is out and the pressure on the barrel to go forward is begins to wane, the barrel is now free to pivot on it's barrel link pivot. The slide is then able to swing back and the cycle begins to occur. ie; the rearward movement of the slide overcomes the forward force of the barrel.
The key to making this work is to have enough weight in the slide plus spring tension to require a certain minimum amount force needed to cycle it (too much and it won't cycle, not enough weight/spring tension and the lock won't work). 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. So lets put this in ft lbs. Using completely made up numbers. The lockup works at 100 ft lbs of force on the barrel going forward but releases at 75 ft lbs. 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. This releases the lock on the barrel. Let's say that there is still 10,000 PSI of pressure still in the barrel at this point. That is what is used to cycle the slide backwards by way of the pressure put on the casing and the barrel. See this video at sec 45. http://www.youtube.com/watch?v=l5PHkv3f-9U You will see a small pressure wave come out of the ejection port, though most of the pressure is relieved out of the front of the barrel, the slide attains enough backwards inertia to cycle.
This is where the slide weight and spring tension comes in. There is a time where the pressure on the barrel is not strong enough (someone mentioned it earlier) to keep the lock engaged. That requires that there is enough inertia* in the slide to allow the pressure to build in the chamber before the slide cycles. If it cycles before the lock is engaged, the lock never engages and the barrel will rise as the bullet is in the chamber. Too much weight and spring tension and the slide can't move back fast and far enough and you exhaust all of the pressure out of the front of the gun without capturing enough for the slide recoil. All of this happens in such small fragments in time that you need a 1200 fps camera or better to catch the action.
To summarize, in very simple terms, the forward pressure on the barrel keeps the slide locked until that forward pressure is relieved (which can't happen until the bullet leaves the barrel). Once it is relieved, the barrel can move backwards allowing the slide to cycle. That's how the locking mechanism works.
* remember relativity, everything has inertia including things at rest or the resistance of any physical object to a change in its state of motion
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Interesting writeup, thanks!
I don't really see where any forward pressure on the barrel comes from, though. If you've got pressure in a plugged tube, force is exerted towards the front wall (bullet), the rear wall (the case/breechface) and the sides.
EDIT: That is, you can move the bullet forward, move the slide/breechface backwards, and (although you don't want to) the sides of the barrel outwards. What mechanism could push the barrel forwards? Friction of the bullet in the barrel?
I do love my internet arguing. It's nice to do it about physics, which generally isn't a topic that'll make you enemies or come back to haunt you in the future.
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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.
smokey-seven
NES Member
Point of order
"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."
No!
For every action there is an equal and opposite reaction.
There is energy imparted from the bullet to the barrel and slide as soon as the bullet starts to move via the friction of the lands and the bullet. The barrel and the locked in slide starts its rearward motion almost immediately as the bullet commences it's motion. (the cartridge base also pushes on the bolt face ie slide) The time taken for the bullet to leave the barrel is less than the time it takes for the barrel to reach its unlocking point and become disengaged from the slide.
"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."
No... see above. Both the slide and the barrel start to move as soon as the bullet movement has overcome the mass of the slide and components.
"The key to making this work is to have enough weight in the slide plus spring tension to require a certain minimum amount force needed to cycle it (too much and it won't cycle, not enough weight/spring tension and the lock won't work)."
There is a basic misconception here. The spring has very little to do with the opening of the action other than to increase the total resistance rearward a bit. The spring is there primarily as a closing device. You could have used a rubber bouncy thing at the rearward travel end and accomplished the same purpose. The spring is a closer and other than adding a very minuscule resistance to opening, not good for anything else. The spring has nothing to do with barrel lock up to the slide with the one exception of closing the slide with enough forward force to allow the mass of the total mechanism to lock itself up and operate the reloading function. It does hold the whole thing closed, but that has nothing to do with the lugs.
"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."
No!
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.
"That is what is used to cycle the slide backwards by way of the pressure put on the casing and the barrel."
It's not pressure, it's force. That 230 grain projectile accelerated to 900 FPS has imparted an equal and opposite force to the weapon, from barrel to slide and over the complete cycle the frame as well.
"This is where the slide weight and spring tension comes in. There is a time where the pressure on the barrel is not strong enough (someone mentioned it earlier) to keep the lock engaged."
The, "pressure on the barrel" is there by virtue of the spring and slide holding it there.
"To summarize, in very simple terms, the forward pressure on the barrel keeps the slide locked until that forward pressure is relieved (which can't happen until the bullet leaves the barrel). Once it is relieved, the barrel can move backwards allowing the slide to cycle. That's how the locking mechanism works."
No!
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.
This is a mechanical force, not a pressure force. The casing of the bullet pushes against the face of the bolt (slide) in an equal and opposite force as the bullet leaving the barrel. There is also some rearward force on the barrel (lands trying to move in the opposite direction of the bullet) which is locked to the slide and thus imparting force to both components.
It's like hitting the barrel and slide with a hammer. This force acts over the .0007 second time and a little more release of gas pressure out the front of the barrel and now we have that force as kinetic energy in the barrel and slide moving rearward until it hits the stop and then the rest is transferred to the frame.
"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."
No!
For every action there is an equal and opposite reaction.
There is energy imparted from the bullet to the barrel and slide as soon as the bullet starts to move via the friction of the lands and the bullet. The barrel and the locked in slide starts its rearward motion almost immediately as the bullet commences it's motion. (the cartridge base also pushes on the bolt face ie slide) The time taken for the bullet to leave the barrel is less than the time it takes for the barrel to reach its unlocking point and become disengaged from the slide.
"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."
No... see above. Both the slide and the barrel start to move as soon as the bullet movement has overcome the mass of the slide and components.
"The key to making this work is to have enough weight in the slide plus spring tension to require a certain minimum amount force needed to cycle it (too much and it won't cycle, not enough weight/spring tension and the lock won't work)."
There is a basic misconception here. The spring has very little to do with the opening of the action other than to increase the total resistance rearward a bit. The spring is there primarily as a closing device. You could have used a rubber bouncy thing at the rearward travel end and accomplished the same purpose. The spring is a closer and other than adding a very minuscule resistance to opening, not good for anything else. The spring has nothing to do with barrel lock up to the slide with the one exception of closing the slide with enough forward force to allow the mass of the total mechanism to lock itself up and operate the reloading function. It does hold the whole thing closed, but that has nothing to do with the lugs.
"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."
No!
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.
"That is what is used to cycle the slide backwards by way of the pressure put on the casing and the barrel."
It's not pressure, it's force. That 230 grain projectile accelerated to 900 FPS has imparted an equal and opposite force to the weapon, from barrel to slide and over the complete cycle the frame as well.
"This is where the slide weight and spring tension comes in. There is a time where the pressure on the barrel is not strong enough (someone mentioned it earlier) to keep the lock engaged."
The, "pressure on the barrel" is there by virtue of the spring and slide holding it there.
"To summarize, in very simple terms, the forward pressure on the barrel keeps the slide locked until that forward pressure is relieved (which can't happen until the bullet leaves the barrel). Once it is relieved, the barrel can move backwards allowing the slide to cycle. That's how the locking mechanism works."
No!
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.
This is a mechanical force, not a pressure force. The casing of the bullet pushes against the face of the bolt (slide) in an equal and opposite force as the bullet leaving the barrel. There is also some rearward force on the barrel (lands trying to move in the opposite direction of the bullet) which is locked to the slide and thus imparting force to both components.
It's like hitting the barrel and slide with a hammer. This force acts over the .0007 second time and a little more release of gas pressure out the front of the barrel and now we have that force as kinetic energy in the barrel and slide moving rearward until it hits the stop and then the rest is transferred to the frame.
In the M1911 design, when the action is closed, and held that way by the spring, the barrel and slide are locked together by the lugs on the barrel fitting into matching recesses in the slide. When the gun is fired, both barrel and slide begin moving back locked together for a short distance, by which time the bullet has left the barrel and pressure has dropped to a safe level. At that point the barrel link pivots the rear of the barrel downward, disengaging the lugs and allowing the slide (and the extracted empty case) to continue backward on their own, continuing to compress the spring, which eventually overcomes the momentum of the slide and then moves it forward to complete the cycle.
The M1911 design, which I agree is brilliant, has nothing really to do with making a semi-auto pistol work because there are obviously any number of working semi-autos that don't share it. The brilliance is in how it keeps the breech closed until the pressure has dropped, which was necessary because of the power of the cartridge. Semi-autos in .22 rimfire and similar low-power cartridges don't need any such fancy locking mechanisms and can operate on simple blowback. The same simple blowback principle would also work fine on more powerful cartridges as well if the slide were made sufficiently heavy, but that would make the weapon impractical to use.
The M1911 design, which I agree is brilliant, has nothing really to do with making a semi-auto pistol work because there are obviously any number of working semi-autos that don't share it. The brilliance is in how it keeps the breech closed until the pressure has dropped, which was necessary because of the power of the cartridge. Semi-autos in .22 rimfire and similar low-power cartridges don't need any such fancy locking mechanisms and can operate on simple blowback. The same simple blowback principle would also work fine on more powerful cartridges as well if the slide were made sufficiently heavy, but that would make the weapon impractical to use.
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