jerkface11
Member
You guys keep confusing recoil operated with blowback. THEY AREN'T THE SAME. Blowback guns do not fire from a locked breech period. And no the barrel on a 1911 doesn't unlock till the bullet is gone.
Action type and physics
- Thread starter Vonderek
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General Geoff
Member
Why does the locked breech have to change the very definition of the action? The movement of the bolt face being pushed rearward is STILL what causes the breech to unlock, and the inertia from the bolt (locked with the barrel at the time) is STILL what causes the slide to move rearward after the breech is unlocked; in effect, this means it's just delayed. "Recoil-operated" is adding a superfluous category to an otherwise fairly simple concept.
1911Tuner
Moderator Emeritus
We're not at all confused jerkface. Do you understand that they both operate from the same thing? Recoil forces. Force forward equals force backward. The force that drives the bullet forward also drives the breechblock backward.
Exactly.
Exactly.
1911Tuner
Moderator Emeritus
Geoff...Methinks that jerkface thinks he's talkin' to a buncha beginners here. 
Jerkface...We're well aware of how the locked breech/recoil operated pistol functions.
I got that part either figured out or explained to me in or around 1962, give or take.
We know that the barrel not only doesn't unlock until the bullet is gone...but that it can't unlock until after the bullet is gone.
We understand that the gun isn't actually locked until it fires...that the "lock" occurs under pressure, because of the bullet exerting a forward drag on the barrel while the opposite force drives the slide backward, and the lugs are engaged under a shearing stress.
We understand that the slide and barrel only move a short distance when the bullet exits.
About 1/10th inch, as it were.
We also understand...and I think that this is the part that you're a little shy of...is that other than the mechanism used to delay the opening of the breech...there is really no difference in the two. They both work based on Newton's 3rd Law of action and reaction.
So...The recoil operated pistol is a delayed blowback, and the blowback...whether straight or delayed...is recoil operated. The two are same-same.
Jerkface...We're well aware of how the locked breech/recoil operated pistol functions.
I got that part either figured out or explained to me in or around 1962, give or take.
We know that the barrel not only doesn't unlock until the bullet is gone...but that it can't unlock until after the bullet is gone.
We understand that the gun isn't actually locked until it fires...that the "lock" occurs under pressure, because of the bullet exerting a forward drag on the barrel while the opposite force drives the slide backward, and the lugs are engaged under a shearing stress.
We understand that the slide and barrel only move a short distance when the bullet exits.
About 1/10th inch, as it were.
We also understand...and I think that this is the part that you're a little shy of...is that other than the mechanism used to delay the opening of the breech...there is really no difference in the two. They both work based on Newton's 3rd Law of action and reaction.
So...The recoil operated pistol is a delayed blowback, and the blowback...whether straight or delayed...is recoil operated. The two are same-same.
1911 Tuner -
I would like to know where you found that radiograph of the 1911 in recoil. That's interesting on multiple levels and worth using as a teaching point, both for 1911's and radiography. I don't doubt it; I just would like to cite it.
I would like to know where you found that radiograph of the 1911 in recoil. That's interesting on multiple levels and worth using as a teaching point, both for 1911's and radiography. I don't doubt it; I just would like to cite it.
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jerkface11
Member
1911's are not delayed blowback they are locked breach. CZ-52's are delayed blowback. Hi-Points are blowback.
Lonestar49
Member
Oh, but they do.. cause lateral movement
1911Tuner's response:
...
I knew there was a reason I kept these shots in my photo file:
Observe the bow and the water line: With a full broadside
Oops.. wrong pic.. But now that I have your attention:
Here's the right ones:
Ls
1911Tuner's response:
...
I knew there was a reason I kept these shots in my photo file:
Observe the bow and the water line: With a full broadside
Oops.. wrong pic..
But now that I have your attention:
Here's the right ones:
Ls
Last edited:
NoAlibi
Member
Misdiagnosis???
The increased density that you are referring is not the distal phalanx of the “second phalanges”.
Fingers are described as digits and phalanges are the three bones (proximal, middle and distal) of a digit and the distal phalanx would never be described as the second of the phalanges. Besides, all the distal phalanges would be out of view because they are obstructed by the pistol.
If you were erroneously referring to the finger with the increased density under the trigger guard as the second finger that would be and error too. The thumb is counted as the first finger, the trigger finger as the second finger and the one under the trigger guard as the third finger.
This would not qualify as a diagnostic x-ray because there is not enough detail. The increased density that you are observing may simply caused by the superimposition of the proximal and middle phalanges and possibly complicated by the focal film distance or even scatter radiation if an appropriate grid was not used.
This poor for diagnosis x-ay does not exclude the possibility of pathology. However, in absence of any clinical information such as edema, inflamation, complaints of pain, reduced range of motion, patient history, etc. further tests would probably not be in order. However, continued vigilance is a safe route to take. If you are worried about a malpractice suit and really don’t care about unnecessary invasive tests and their attendant high costs, then by all means go ahead and order more tests. Damned if you do and damned if you don’t IMO.
If this x-ray was take in 1916, it would seem that the shooter wouldn’t need or be available for more testing anyway!
Do you think that since you made an error looking at that x-ray there is a possibility you may have made an error in looking at those videos?
Physics was a required course for my undergrad degree and I’ll have to admit that it was a looong time ago and I don’t have any of my texts to corroborate your explanation of collisions.
If memory serves, and it may not, all collisions were classified as either elastic or plastic and I don’t recall that a plastic (inelastic by your description?) could become an elastic collision. Plastic and elastic collisions were defined at their outset and I’m unaware that either can change in a time continuum. I would like to see a reference to update my understanding of those principles.
If your physics are in error, do you think there may be a possibility that you may have made an error in your explanations?
The increased density that you are referring is not the distal phalanx of the “second phalanges”.
Fingers are described as digits and phalanges are the three bones (proximal, middle and distal) of a digit and the distal phalanx would never be described as the second of the phalanges. Besides, all the distal phalanges would be out of view because they are obstructed by the pistol.
If you were erroneously referring to the finger with the increased density under the trigger guard as the second finger that would be and error too. The thumb is counted as the first finger, the trigger finger as the second finger and the one under the trigger guard as the third finger.
This would not qualify as a diagnostic x-ray because there is not enough detail. The increased density that you are observing may simply caused by the superimposition of the proximal and middle phalanges and possibly complicated by the focal film distance or even scatter radiation if an appropriate grid was not used.
This poor for diagnosis x-ay does not exclude the possibility of pathology. However, in absence of any clinical information such as edema, inflamation, complaints of pain, reduced range of motion, patient history, etc. further tests would probably not be in order. However, continued vigilance is a safe route to take. If you are worried about a malpractice suit and really don’t care about unnecessary invasive tests and their attendant high costs, then by all means go ahead and order more tests. Damned if you do and damned if you don’t IMO.
If this x-ray was take in 1916, it would seem that the shooter wouldn’t need or be available for more testing anyway!
Do you think that since you made an error looking at that x-ray there is a possibility you may have made an error in looking at those videos?
Physics was a required course for my undergrad degree and I’ll have to admit that it was a looong time ago and I don’t have any of my texts to corroborate your explanation of collisions.
If memory serves, and it may not, all collisions were classified as either elastic or plastic and I don’t recall that a plastic (inelastic by your description?) could become an elastic collision. Plastic and elastic collisions were defined at their outset and I’m unaware that either can change in a time continuum. I would like to see a reference to update my understanding of those principles.
If your physics are in error, do you think there may be a possibility that you may have made an error in your explanations?
Hud
Member
1911Tuner
Moderator Emeritus
Oro..I've had that thing for so long, I don't remember. Only that it was an ordnance picture...likely taken at Colt. You might try there.
Jerkface...I'd suggest that you think on it a bit longer...but I'll try one more time, just for the sake of broadening your understanding.
The only differences between the straight blowback and the recoil operated pistol is the slide on the latter doesn't move independently of the barrel...and the mechanism used to delay the breech opening.
That's it. That's the only difference.
There are many mechanisms that can be used to delay the breech opening in a delayed blowback. For instance...Heckler and Koch's G-3/91 rifles use a pair of spring-loaded rollers that cam into mating recesses in the receiver. Still others use gas, cams, toggles, or even springs to effect the delay.
The blowback...delayed blowback...and the recoil operated pistol ALL function by means of force forward/force backward, action and reaction...or in other words...recoil. The locked breech design uses the bullet itself as its most prominent delaying mechanism.
Like General Goeff pointed out to you so elegantly. (Paraphrased) "Recoil Operated" is a term that muddies up the water and lends unnecesary complication to what is a very simple operating principle.
Several years ago, one of the top gunsmithing schools in the world stopped referring to the 1911, the P-08 Luger, and others as recoil operated...and started describing them as delayed blowback in operation...because that's what they are.
Like this:
Bullet<---{BANG}--->slide
The fact that the barrel goes along for the ride for a short distance is incidental.
Jerkface...I'd suggest that you think on it a bit longer...but I'll try one more time, just for the sake of broadening your understanding.
The only differences between the straight blowback and the recoil operated pistol is the slide on the latter doesn't move independently of the barrel...and the mechanism used to delay the breech opening.
That's it. That's the only difference.
There are many mechanisms that can be used to delay the breech opening in a delayed blowback. For instance...Heckler and Koch's G-3/91 rifles use a pair of spring-loaded rollers that cam into mating recesses in the receiver. Still others use gas, cams, toggles, or even springs to effect the delay.
The blowback...delayed blowback...and the recoil operated pistol ALL function by means of force forward/force backward, action and reaction...or in other words...recoil. The locked breech design uses the bullet itself as its most prominent delaying mechanism.
Like General Goeff pointed out to you so elegantly. (Paraphrased) "Recoil Operated" is a term that muddies up the water and lends unnecesary complication to what is a very simple operating principle.
Several years ago, one of the top gunsmithing schools in the world stopped referring to the 1911, the P-08 Luger, and others as recoil operated...and started describing them as delayed blowback in operation...because that's what they are.
Like this:
Bullet<---{BANG}--->slide
The fact that the barrel goes along for the ride for a short distance is incidental.
1911Tuner
Moderator Emeritus
Hud...Good picture. Wonder how long it took to time that just right.
1911Tuner
Moderator Emeritus
yes, Jerkface. We understand why the barrel tilts. Do you?
The barrel tilts in order to let the upper lugs engage the mating lug recesses in the slide. It's not the locking mechanism. It's necesary to get the lugs engaged.
For the record. The barrel engages with the slide vertically. The breech locks horizontally...when the gun fires.
deadin
Member
If the M1911, P08, etc. are "delayed blowback", what are the Remington M51, the Italian Glisenti and the several models of Savage auto-loaders? (or are we just going to lump them all together?)
Along the same lines what about the Frommer Stop and the Schwarzlose?
There was also a rifle designed by Pedersen that unlocked the bolt based on primer set-back.
Along the same lines what about the Frommer Stop and the Schwarzlose?
There was also a rifle designed by Pedersen that unlocked the bolt based on primer set-back.
1911Tuner
Moderator Emeritus
IIRC, the Gilsenti is technically a delayed blowback, but not a locked breech in the pure sense. Kinda fuzzy, but it employed a mechanism that had a lever that held a separate breechblock against the barrel until the pressures had dropped enough for safe opening. Obturator? Seems like that's the term.
Lord...I haven't seen one of those ugly things in 35 years. Reminded me of the Nambu.
Here's a short description of the M51 Remington. A very pretty pistol to my eyes, but I've never had my hands in one.
Lord...I haven't seen one of those ugly things in 35 years. Reminded me of the Nambu.
Here's a short description of the M51 Remington. A very pretty pistol to my eyes, but I've never had my hands in one.
deadin
Member
The Schwarzlose is a "blow forward" so there is no way it can be called a "blow-back".
The Frommer Stop is the only example of a Long Recoil action pistol I've ever seen. (I believe the British Mars may have used this system also.)
The barrel and breech stay locked together through the entire rearward function. Once they both reach the back of travel, they are unlocked and the barrel returns to battery, ejecting the case on the way. When the barrel has returned forward, the breech (slide, bolt) is released and travels forward , picking up and chambering a fresh cartridge. A very interest piece of mechanics.
To me the mystifying part is just why Frommer decided to use this complicated system on a .32 Auto.
The Frommer Stop is the only example of a Long Recoil action pistol I've ever seen. (I believe the British Mars may have used this system also.)
The barrel and breech stay locked together through the entire rearward function. Once they both reach the back of travel, they are unlocked and the barrel returns to battery, ejecting the case on the way. When the barrel has returned forward, the breech (slide, bolt) is released and travels forward , picking up and chambering a fresh cartridge. A very interest piece of mechanics.
To me the mystifying part is just why Frommer decided to use this complicated system on a .32 Auto.
1911Tuner
Moderator Emeritus
Oh, yeah! That thing! Barrel gets dragged forward by the bullet and takes the breechblock with it. I remember reading about it a few years back. Interesting design.
Anyway...Back on topic.
Everybody understand that the slide moves while the bullet is in transit, and that the bullet is the main delaying factor in the locked breech pistol?
Excellent!
On to straight blowback.
Well...The slide gets pushed back by the same force that pushes the bullet with no mechanical connection between slide and barrel. The necessary delay comes from slide mass and recoil/action spring resistance.
Simple, what?
Jerkface! Got it all sorted out?
I'll recap:
Regardless of whether it's a straight blowback...a delayed blowback...or a recoil operated weapon...they all function from recoil forces imposed on the breechblock. Or...as Geoff noted...gas/piston operated.
The Colt-Browning tilt-barrel design engages vertically and locks horizontally.
SaMx
Member
I thought that in a blowback (delayed or otherwise) operated gun, the main force that cycles the action is the gas pressure pushing back on the cartridge. I don't see how a locked breech gun like the 1911 can work that way at all, considering that the barrel doesn't unlock from the slide until after the bullet has left the barrel and the pressure inside the barrel has vented out the muzzle.
1911Tuner
Moderator Emeritus
It's the only force. it's also the only force that drives the slide rearward in the locked breech pistol. It's the only force available in either one.
The fact that the barrel doesn't unlock/disengage from the slide until the bullet exits doesn't have anything to do with what drives the slide. The same mechanism that drives it rearward in the blowback drives the slide in the locked breech pistol.
A brief description of the locked breech pistol is in order.
The bullet and slidestart to move at the same time.
The slide pulls the barrel backward with it.
At 1/10th inch...nominally...the barrel reaches the very beginning of the linkdown point. At or just before this point, the bullet exits.
The barrel links down. At .250 inch of slide movement, the barrel is completely disengaged, and the slide continues to move rearward on conserved momentum.
Go to Page 1 and watch the video that I linked to on post #21. Pay special attention to the very last 1911 in the sequence...and at the x-ray picture of the pistol in operation in post #40, and note the position of the link.
PS
Kuhnhausen's Balanced Thrust Vector description is dead wrong. Can't happen.
SaMx
Member
so you're saying that the force of the pressure pushing back on the breech face is what pushes back the slide on a 1911, while the slide is locked to the breech? That's just not possible, any more than a piston, locked to a cylinder so that it doesn't move relative to the cylinder, will push the whole piston-cylinder assemble backwards.
p.s. I have no idea what Kuhnhausen's Balanced Thrust Vector is, but I do have a decent understanding of physics, and it seems pretty clear that a locked beech weapon can't be operated by the gas pressure in the barrel acting on the breech face.
p.s. I have no idea what Kuhnhausen's Balanced Thrust Vector is, but I do have a decent understanding of physics, and it seems pretty clear that a locked beech weapon can't be operated by the gas pressure in the barrel acting on the breech face.
1911Tuner
Moderator Emeritus
That's exactly what I'm saying...and that's the reality. It's the only compelling force that's available.
There is nothing else that can do it.
And...The slide isn't locked to the breech. The slide is locked to the barrel. The junction of slide and barrel is the breech.
The slide is driven rearward, and the barrel is pulled rearward with it. Hand-cycle the slide on your pistol, and watch the barrel move backward a short distance and start to drop. That's exactly how it works when it's fired, except the force comes from within...between the bullet and the breechblock.
Go push on an object. The instant that you start to push, you get pushed. The force is supplied by your arm. Your body is one side of the action/reaction force pair.
Go pull on an object. You get pulled.
Better yet...Go watch the video.
SaMx
Member
I know that the barrel and slide move backwards together, that is why it's not possible for the gas pressure pushing on the breech face to be the force pushing the slide and barrel backwards.
SaMx
Member
think of it this way
the barrel is like a cylinder, that's open at both ends, with a piston in each end. One has low mass (the bullet) and the other piston has a large mass (the bolt/slide). In a straight blowback, the gas pressure inside the cylinder will accelerate both pistons. the low mass one will accelerate much faster, and the high mass one will accelerate more slowly. when the time the low mass piston leaves the cylinder, the gas pressure is vented, and the heavy piston continues moving back against the recoil spring because of it's momentum.
In a locked breech pistol, the heavy piston is locked into place, so it cannot move relative to the cylinder. What force is pushing the cylinder and piston that is locked to it backwards? The recoil force is.
the barrel is like a cylinder, that's open at both ends, with a piston in each end. One has low mass (the bullet) and the other piston has a large mass (the bolt/slide). In a straight blowback, the gas pressure inside the cylinder will accelerate both pistons. the low mass one will accelerate much faster, and the high mass one will accelerate more slowly. when the time the low mass piston leaves the cylinder, the gas pressure is vented, and the heavy piston continues moving back against the recoil spring because of it's momentum.
In a locked breech pistol, the heavy piston is locked into place, so it cannot move relative to the cylinder. What force is pushing the cylinder and piston that is locked to it backwards? The recoil force is.
1911Tuner
Moderator Emeritus
The slide is driven backward, and pulls the barrel backward with it.
We understand that. The question is...Do you understand what generates recoil?
Recoil is not a force. Recoil is the result of a force applied...just like bullet acceleration through the barrel is the result of force applied.
Force forward equals force backward. The only force that's available is the force that comes from the burning, expanding gasses.
And what is it exactly that makes the locked breech pistol any different...aside from the barrel mass being added to the slide's for a short time? Exactly?
Go watch the video.
SaMx
Member
Ok, I guess you could consider it to be kind of like a piston inside of a piston.
yes, I understand what causes recoil. conservation of momentum is responsible for recoil, and you could also explain the rearward motion of the locked piston-cylinder system in terms of conservation of momentum, which would make the gun recoil operated.
I think this is a situation where you have to different models that both explain the same physical phenomena.
yes, I understand what causes recoil. conservation of momentum is responsible for recoil, and you could also explain the rearward motion of the locked piston-cylinder system in terms of conservation of momentum, which would make the gun recoil operated.
I think this is a situation where you have to different models that both explain the same physical phenomena.
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