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How does the 1911 really work?
JohnT
Member Posts: 384 ✭✭✭
Some time ago, an article appeared in the American Rifleman by Jerry Kuhnhausen titled: How the 1911 Really Works.
It was beautifully illustrated and written in great detail...and it was utterly wrong. Not all of it, of course. I'm speaking of the "Balanced Thrust/Force Vector" description in which Kuhnhausen stated that the bullet exits, breaking the balanced thrust vector, allowing the slide to move rearward in recoil.
Can't happen. Not because I say so, but because a very sharp guy named Isaac Newton said so about 50 years ago.
To wit:
"For every action, there must be an equal and opposite reaction."
For the record...assuming a condition of zero headspace...the slide starts to move at the same instant that the bullet starts to move. If the slide stands still until after the bullet exits, the slide won't move...at least not enough so you'd notice.
In a nutshell, the slide moves nominally 1/10th inch at the point of bullet exit. Just as...or just after that happens...the link starts to draw the barrel downward, disengaging the upper lugs vertically from the slide. Vertical disengagement can't occur if the bullet is still present, and the system under pressure because the lugs are locked horizontally under opposing shear forces...and if it tries to, the link and the upper lugs will be damaged quickly.
At .200 inch of slide travel, the upper lugs are completely disengaged, and at .250-inch...the barrel is fully linked down and clearance between the top of the barrel and the slide is established...and the barrel drops the final .003 inch or so to the bed. This assumes that the barrel is properly timed and all is within spec.
Again...the slide is moving while the bullet is moving. It doesn't move far, but that's why it's called "Short" recoil operated. Once the bullet has exited, the force that drove the system exits behind it, and there's no force remaining the drive the slide rearward. All motion of both the slide and the bullet is, at that point, a function of momentum conserved during the time that they were being accelerated...and neither one can accelerate to a higher velocity without the application of a new force.
Here is a very old fluroscoped photo of a 1911 during the firing sequence. Take note of the link's position. The barrel has moved backward...dragged by the slide...and the link has moved almost to the point of starting linkdown. Take note also of the alignment of the slide and frame at the rear. The slide has moved approximately .070 inch, give or take, and the base of the bullet approximately one inch from the muzzle...and that's just about right.
If you look closely, you can see the bones in the shooter's hand. Note that the gun has moved upward very little as the slide hasn't impacted the frame.
Interesting old picture. It explains a lot.
It was beautifully illustrated and written in great detail...and it was utterly wrong. Not all of it, of course. I'm speaking of the "Balanced Thrust/Force Vector" description in which Kuhnhausen stated that the bullet exits, breaking the balanced thrust vector, allowing the slide to move rearward in recoil.
Can't happen. Not because I say so, but because a very sharp guy named Isaac Newton said so about 50 years ago.
To wit:
"For every action, there must be an equal and opposite reaction."
For the record...assuming a condition of zero headspace...the slide starts to move at the same instant that the bullet starts to move. If the slide stands still until after the bullet exits, the slide won't move...at least not enough so you'd notice.
In a nutshell, the slide moves nominally 1/10th inch at the point of bullet exit. Just as...or just after that happens...the link starts to draw the barrel downward, disengaging the upper lugs vertically from the slide. Vertical disengagement can't occur if the bullet is still present, and the system under pressure because the lugs are locked horizontally under opposing shear forces...and if it tries to, the link and the upper lugs will be damaged quickly.
At .200 inch of slide travel, the upper lugs are completely disengaged, and at .250-inch...the barrel is fully linked down and clearance between the top of the barrel and the slide is established...and the barrel drops the final .003 inch or so to the bed. This assumes that the barrel is properly timed and all is within spec.
Again...the slide is moving while the bullet is moving. It doesn't move far, but that's why it's called "Short" recoil operated. Once the bullet has exited, the force that drove the system exits behind it, and there's no force remaining the drive the slide rearward. All motion of both the slide and the bullet is, at that point, a function of momentum conserved during the time that they were being accelerated...and neither one can accelerate to a higher velocity without the application of a new force.
Here is a very old fluroscoped photo of a 1911 during the firing sequence. Take note of the link's position. The barrel has moved backward...dragged by the slide...and the link has moved almost to the point of starting linkdown. Take note also of the alignment of the slide and frame at the rear. The slide has moved approximately .070 inch, give or take, and the base of the bullet approximately one inch from the muzzle...and that's just about right.
If you look closely, you can see the bones in the shooter's hand. Note that the gun has moved upward very little as the slide hasn't impacted the frame.
Interesting old picture. It explains a lot.
Comments
quote:ME THINKS YOU HAVE BEEN LISTENING TO YOUR DOG WAY TOO MUCH
Why so? Do you not even believe your eyes?
Or do you think that Newton's 3rd Law was merely a theory?
Tell me, do.
An explosive placed between two objects, in this case a bullet and a gun, will blow both objects in opposite directions, and if one of the objects is lighter or otherwise has less resistance, it will move the fastest.
Recoil begins when the bullet starts from the case, and different loads are why the muzzle is at different points of rise with common firearms designs, at the moment of bullet exit. That is why a given gun will shoot to different points of aim with various loads.
dcs shooters...If you don't understand basic physics, you're stuck. I suggest that you drop by a local community college and speak with a physics teacher.
But, I'll try one more time.
An object at rest will remain at rest unless and until an outside force is imposed on it. This is basic. Objects don't move unless they're forced to move.
The slide is an object.
On to Newton 3...the Law of Action and Reaction.
For every action, there must be an equal and opposite reaction. Equal being the operative word. Equal in every way.
An action/reaction system requires three things.
Two interacting objects and a vectored force between them.
Remove either one of those things, and you can't have an
action/reaction event.
If you push on an object using your arms, you are one reactive mass
and the object is the other reactive mass. Your arms provide the force.
When you push on that object, you immediately get pushed via the vectored force that exists between you and the object.
Likewise, if you pull on an object using your arms, you immediately
get pulled via the vectored force. This is inescapable.
The magnitude of force that you provide is exerted equally in both directions. Force forward is force backward. Equal and opposite.
If the object is removed from contact, you may push, but the object won't move because there is no force acting on it. Neither will you move because there is no reactive mass for the force to use to push you. No force=No motion.
If the bullet exits before the slide moves, the slide won't move because there's no reactive mass for the force to use to push the slide. Once the bullet exits the closed system, the
system loses one of the three things needed to have an action/reaction event...and as the force follows it a nanosecond later...it loses two of the three.
Therefore, Kuhnhausen was...mistaken.
The Colt Commander was my first build [;)]
I built these for myself, learned from the best to do it [:)]
I understand very well how a 1911 works [^]
Whoops! Meant 500 years ago on that Newton thing. Mea Culpa.
Try 325 years ago.
Sir Isaac Newton, 1642-1727.
He published his Principia, which summarized his famous three laws of motion, in 1687.
Well...I wasn't puttin' ya down. I was askin' if you understood basic Newtonian physics, the 1st and 3rd Laws in particular.
As for building...My dance with Johnny's Toy started in 1965 with my first rebuild. It was an old, worn Ithaca, done under the watchful eye of my father and uncle...a toolmaker turned engineer and retired Navy armorer respectfully. I still have the gun, but rarely shoot it. The old pistols are soft, and don't hold up well to 25-30k a year except with "Softball" ammunition...which also ain't my thing.
Over the next 48 years, most of my work has been in the rebuilding of such pistols...both USGI and commercial...addressing functional and/or reliability issues, and returning them to serviceable condition, and I've had my hands in a buncha pistols over the course of those years.
I've dabbled in some custom work, but found that it wasn't really my cuppa Joe...so I left that to the guys with the patience and people skills and stuck to just bein' a mechanic...a problem fixer. Until recently, I also did some accuracy work, including barrel fitting...but my eyes have gotten so bad that I can't do it justice any more.
Back when I did the job for a friend who was a FFL dealer...as a second job...I gained a local reputation for it. Many of the guys who couldn't recall my name would come in and ask for that guy who tunes up 1911s...and that evolved into "That 1911 Tuner." 20 years later, when I discovered these forums...that became my first username.
Nowadays, I mostly do a little pro bono work for the workin' stiffs who've saved their nickels and dimes and bought their pistols, and discovered that they won't run. Since I don't have an FFL any more, nor access to one via contract work...I can't accept money or anything of value, and I have to do it while the owner waits, bonds with the dogs, and partakes of my infamous turbo coffee. On the upside, I've met several good people, and made a few lasting friends. It's also allowed me to keep my hand in something that I once loved, but failing eyesight has forced me to limit any precise work.
quote:Try 325 years ago.
Pickypickypicky. I said "about."
Operating a dog rescue, with 16 of the critters on-site...I often have to hit these discussion boards on the run. My day usually ends at 2200 and begins anew at 0400. Sometimes my time frames are a bit loose, and many times, I have to write up a response or an explanation/description on a notepad a little at a time...then cut and paste it between dancin' with the wolves. Sometimes typos also abound, and some points aren't clearly explained.
So, try to bear with an old man with bad eyes and too much on his plate. I does the bestest I can with what I got.
This is a "Black Army Commander" that resulted from the mating of a junk 1918 USGI Colt with the slide cracked in the breechface and lugs so badly beaten back that it'd never headspace anyway...and a Series 80 Commander top end bought at a gun show because the price was too good to pass up. The frame rails were so worn swaging and peening for a decent fit would have been futile.
I bought the old Colt as a parts gun, and it laid in the back of the vault for nearly 30 years. The Commander top was bought in the late 90s. They came together in 2007.
As luck would have it, the slide rails were nearly minimum spec, and just a little swaging all but eliminated the vertical slop...so I set to work creating a pre-A1 Faux General Officer's Model.
Rather than machining the rails and impact abutment .100 inch to accommodate the Commander slide, I decided to go the easy route and chuck a FLGR up in the lathe and thin the flange from the rear to .050 inch in order to regain some of the lost travel and runup.
Why? Because it was there, and because a snarky, condescending "expert" said that it couldn't be done without machining the frame.
I had to use an extended ejector and a bit of "engineering" on the length and nose geometry to tweak the ejection...but patience and a good measure of stubborn eventually prevailed. The little pistol runs like a Singer sewin' machine...no pun intended...and it draws some interesting "Whiskey Tango Foxtrot" comments when I take it to the range. Maybe I'll even get around to bluing it one day...or not.
The expert was a bit baffled by all this, which made the effort worth it.
I did swap out the arched mainspring housing for a flat, smooth original not long after this was taken. Found it in a junk parts box at a Charlotte Expo show...for two bucks...guts still in it.
Knowledgeable. Information can be a good thing. The building and shooting of 1911 type pistols has been done for at least 60 Years . There is no reason to reinvent the wheel on what works and what is JUST BLING. IMHO The old school Master Pistol smiths were the BEST of working with WHAT THEY HAD . There were No Brownell's offering Match grade parts . They had to use there SKILLS to turn a VERY good pistol into a GREAT PISTOL Check out the date this was built .Also notice the group size and how much it cost to Mail this to the owner.
You are indeed very versed in the 1911 arena. I am thinking you are more versed than the 1911 arena can benifit from. Perhaps your real fortay might encircle invention, since you are also very stout with the theory's of physics, both old and new. In otherwords, perhaps you should work on designing something, to be the equal or greater of the Browning designed 1911, instead of touting all of the greatness of the 1911, that quite a few of us here, already know. Really, believe it or not, you are not the first to spin the 1911 wheel.
Best