Back in the mid-60s, an article appeared in the American Rifleman by Jerry Kuhnhausen, along with step-by-step illustrations titled: "How the 1911 Really Works."
It was well written and illustrated...hat tip to the artist...and seemed to be a very informative description, until he got to this part:
"The bullet exits the muzzle, breaking the Balanced Thrust Vector, allowing the slide to recoil."
Whoa! Full stop, Jerry! That can't happen.
This appeared in the early copies of his 1st Edition, and apparently somebody whispered in his ear...and from that point through the 2nd Edition, he tried to walk it back...then dropped the subject for his 3rd Edition.
Kuhnhausen's credibility took a serious hit among people who understood the gun and understood Newton's 1st and 3rd laws. The unwritten part of those laws governing motion is that balanced forces can't coexist with motion. If the object is moving, the forces have become unbalanced. If the forces are balanced, the result is equilibrium. There ain't a Plan C.
Speaking specifically to Newton 1: An object at rest will remain at rest unless and until an outside force is brought to bear on that object, and that force must be of sufficient magnitude to overcome the frictional and inertial forces resisting acceleration.
Once the bullet has exited, the action side of the Action-Reaction system is missing...and the two forces that drove it...are gone. As far as the slide is concerned, they were never there. There is no force left in the system to cause the slide to move. Simply put, if the slide doesn't move until the bullet exits, the slide won't move.
And, before the claims of "Jet Effect" of the gases exiting behind the bullet providing an accelerating force to the slide start...
I calculated it. Using 5 grains of gas...because the typical powder charge in a .45/230 grain round is about 5 grains...and taking a best wildass guess of 2,000 fps exit velocity for that gas...The recoil impetus on the slide is rougly equal to 1/3rd of that provided by a standard velocity .22 Short. (29 grains at 1,000 fps)
And that was giving it credit for all the gas produced, which...because of blowby and gas exit ahead of the bullet...it never gets. So, a better estimate would probably be closer to 1/4th the .22 Short. The slide would "feel" a slight bump, but that's about it. Certainly not enough to drive it to full travel.
To give him partial credit, he at least understood that the bullet's frictional forward drag on the barrel has a substantial effect on the slide's acceleration, so there's that. The rest of his "Balanced Thrust Vector" description was utterly wrong. Kuhnhausen was no doubt a talented and knowledgeable gunsmith, but the sad truth is that he just didn't understand recoil operation. There are other points that he missed, but I'll leave it at this. I'd have to dig up my copy of Volume One and try to find them all, and I'm just a too little lazy these days.
Cheers!
It was well written and illustrated...hat tip to the artist...and seemed to be a very informative description, until he got to this part:
"The bullet exits the muzzle, breaking the Balanced Thrust Vector, allowing the slide to recoil."
Whoa! Full stop, Jerry! That can't happen.
This appeared in the early copies of his 1st Edition, and apparently somebody whispered in his ear...and from that point through the 2nd Edition, he tried to walk it back...then dropped the subject for his 3rd Edition.
Kuhnhausen's credibility took a serious hit among people who understood the gun and understood Newton's 1st and 3rd laws. The unwritten part of those laws governing motion is that balanced forces can't coexist with motion. If the object is moving, the forces have become unbalanced. If the forces are balanced, the result is equilibrium. There ain't a Plan C.
Speaking specifically to Newton 1: An object at rest will remain at rest unless and until an outside force is brought to bear on that object, and that force must be of sufficient magnitude to overcome the frictional and inertial forces resisting acceleration.
Once the bullet has exited, the action side of the Action-Reaction system is missing...and the two forces that drove it...are gone. As far as the slide is concerned, they were never there. There is no force left in the system to cause the slide to move. Simply put, if the slide doesn't move until the bullet exits, the slide won't move.
And, before the claims of "Jet Effect" of the gases exiting behind the bullet providing an accelerating force to the slide start...
I calculated it. Using 5 grains of gas...because the typical powder charge in a .45/230 grain round is about 5 grains...and taking a best wildass guess of 2,000 fps exit velocity for that gas...The recoil impetus on the slide is rougly equal to 1/3rd of that provided by a standard velocity .22 Short. (29 grains at 1,000 fps)
And that was giving it credit for all the gas produced, which...because of blowby and gas exit ahead of the bullet...it never gets. So, a better estimate would probably be closer to 1/4th the .22 Short. The slide would "feel" a slight bump, but that's about it. Certainly not enough to drive it to full travel.
To give him partial credit, he at least understood that the bullet's frictional forward drag on the barrel has a substantial effect on the slide's acceleration, so there's that. The rest of his "Balanced Thrust Vector" description was utterly wrong. Kuhnhausen was no doubt a talented and knowledgeable gunsmith, but the sad truth is that he just didn't understand recoil operation. There are other points that he missed, but I'll leave it at this. I'd have to dig up my copy of Volume One and try to find them all, and I'm just a too little lazy these days.
Cheers!
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