How does it work?

[Jim Keenan]

Since a previous thread has engendered a lot of discussion, I will play "bad boy" again and start another one with a simple question.

How does the Luger work?

One expert writer has stated that the gas pressure simply blows the breechblock to the rear and that the toggle train is "German overengineering".
Another calls the idea that the breech is locked a "myth".
A third says the gun breech is held closed by the friction of the bullet against the rifling in the barrel.
A fourth says the barrel moves when the gun is opened manually, but not when it is fired.

Can they all be right? How does the Luger work?

And a question of my own. If the barrel were blocked so the bullet could not move at all, what would happen when the gun was fired?

[Mr. Tinker, if you think this will cause too much thinking among the "true gospel" folks, please delete this posting, and I am off this forum.]

Jim

[Edward Tinker]

Jim, as moderator, my job is to keep things civil. As an example, if for some wild reason, you started to talk Nazi politics, I'll warn you, then probably delete the topic.

Other topics, well, it depends on how they go, and on the "other" topic, well it was going no where and getting hot. I would have done the same for anyone, and nothing was personal.

I enjoy your posts and sure as spit don't want ya to go away.

To me, I am interested in how the Luger works, but don't have the background to reply intellgentlmenly,

Ed

[Johnny C. Kitchens]

None of those descriptions even come close to describing how the gun works. First it should be said, I think, that the toggle lock comes from one of Americas great engineers and inventors, Sir Hiriam Maxim. After noticing a steam engine needing to be bumped off of top dead center to get it running, he applied the idea to machine gun. The toggle lock can be looked at as a form of piston, rod, and crankshaft. The bump needed to get it off top dead center comes during the recoil of the main mechanism.Maxims work to simplify and make the system simpler made the toggle lock machine gun, the dominating weapon of World War I. It seems that everyone was trying to figure out some way to use the design. An American, Borchardt, took the idea and put it into a pistol form. Though far from ideal, it was quite functional. It would be up to a man named Luger to take the design to the best known form, which is truly simplified over the predecessor.

I don't know where you found these "expert writers", but I would like to know there names, so I can put them on a list of to be avoided. I do hope you have read other explinations of how the Luger works.

As I see it, the Luger is a short recoil operated handgun, that upon firing, the barrel, receiver, and toggle move rearward. After a short distance rearward, the center pivot point of the toggle is pushed upward by the ramps at the rear of the frame. At that point the barrel and framed are stopped. The toggle continues to fold upward, pulling the breachblock rearward with the now empty casing. Due to the time it takes to recoil the parts, the bullet has cleared the barrel, and the pressure drops to a safe level. By the time the toggle has reached its maximum travel, ejection of the expended case has taken place. The spring in the grip, begins to return the toggle to battery, picking up a fresh round from the magazine, if one is there. The round is chambered, and the barrel and receiver are returned to battery ready for the next shot.

Blocking the barrel in anyway so the bullet couldn't move, is horrible way to produce a bunch of junk, not to mention what might happen to your hand if you are holding it...

[Jim Keenan]

Darn it, Johnny. You came up with the answer so quick this thread was no fun. You are right. The Luger is a recoil operated pistol. The recoil of the barrel and receiver begins at the same time the bullet starts to move, but the bullet is much lighter and moves faster, so it is out the barrel before the gun is fully unlocked. The whole purpose, of course, was to allow that pressure drop. If locking was not used, as in a straight blowback, powerful cartridges would burst when the breech opened. (There are ways to get around this (e.g, Astra, Hi-Point), but most designers chose a locking system.)

The Borchardt, by the way, opened when the rear of the rear toggle (which had roller bearings) was cammed down by the curve inside the frame. One of Luger's changes was to operate the toggle off the curved surfaces on the top of the frame.

As to blocking the barrel and firing the gun, the answer is that nothing happens. (This is NOT true if the bullet is allowed to move and build up kinetic energy; then the barrel will burst.)

But if the bullet is completely blocked so it never moves, the gun cannot open (it is recoil operated and without bullet movement there is no recoil), and it simply sits there, locked, as the pressure leaks out. I will not describe the method, (it's in the "do not try this at home" category") but I have done this with both a M1911 and a Luger.

Unfortunately, I don't recall who wrote that other garbage, but it was all from the gunzine writers who always claim to be experts.

Jim

[Ron Wood]

Johnny was quick on the draw, and of course correct. I would like to add two small embellishments to his description. â??At that point the barrel and frame are stoppedâ?� is just a slip of the tongue so to speak...It is actually the barrel and receiver which are stopped...by the impact of the receiver lug on the rear of the front frame well. The inertia of the breechblock and toggle train causes this assembly to continue to the rear. The toggle reaches its maximum travel when the rear extension of the toggle pivots down and contacts the frame thus stopping the motion of the toggle/breechblock assembly (the â??toggle slapâ?� can be seen on the rear of the frame of any Luger that has been fired more than a few times). The recoil spring then takes over and returns the toggle train/breechblock to battery.

Of course there are other things happening in this wonderful mechanical process, such as the retraction of the firing pin by the cam arm on the forward toggle link, ejection of the spent case, etc., but the major functions are as described.

Too bad you can't recall the names of the "experts". I have never encountered that rubbish and was curious who might have written it.

[Jim Keenan]

Ron, I think it is that the Luger has always been a mystery to the gunzine type writer. It is just not the "straight back" operation that they can handle. Everyone can understand pressure pushing backwards, not everyone can accept Newton's laws, which require (to me) a bit of faith.

Those "quotes" were not from one source or one writer, but an accumulation over a period of years. Some have also been used to "explain" the operation of other recoil operated pistols, like the Model 1911 .45.

Incidentally, I have a Borchardt that is not in so good a condition that I am unwilling to strip it down. Is anyone interested in pictures of the internals and how they go together, or would it be information already well known to the folks here?

Jim

[Ron Wood]

If you are willing to disassemble it and take pictures, there are a ton of folks around who have never seen a Borchardt, let alone the innards, so I am sure it would be information well received. I am one of the few people I know that has been rash enough to tear a Borchard down all the way. It also was not a pristine gun (although it did have a 2 digit serial number) and it wasn't that difficult to disassemble. I was careful and noted how it came apart, so it went back to gether OK. In retrospect, I wish I had taken pictures then.

[unspellable]

Jim,

I should be very interested in hearing the details of your experiments involving constraining the bullet from any movement. It is true that in a recoil operated firearm there would be no recoil under such a condition and the action would not unlock in the normal way. How ever I would expect some extremely high pressures inside the chamber and not be at all surprised to see the pistol blow apart. We might fear for the safety of the pistol if an overweight bullet were loaded in front of a normal powder charge and allowed to move forward in the normal way.

If the bullet is allowed to move and strike an object in the barrel, it is not the kinetic energy of the bullet that does the damage but the standing wave set up in the gas inside the barrel. Or at least that's the conventional theory. I suppose the bullet would tend to deform on striking an object and expand sideways, exerting some pressure on the barrel walls.

On the other hand, I have seen an experiment in which a S&W revolver was fitted with a barrel with no hole through it so that the bullet would move forward in the chamber and stop when it struck the solid breech face of the barrel. In this experiment the revolver did not come unglued.

It is a fact that it is possible to fire a 9 mm Parabellum cartridge in a 7.63 mm Mauser chambered C96 Broom Handle and not have it come unglued. I used to regard this as an apocryphal claim until I ran into an actual case of it. (A highly not recommended practice. If your Broom Handle does not come apart on the first try it will on the umpty eleventh try.)

I have a research project going on the internal ballistics of the Luger and so am particularly interested in your story. Contact me via private message if you do not want to broadcast the details.

[Jim Keenan]

Hi, Un,

No problem except I didn't want to give folks too many ideas for a "DYI" try.

The pistol will not blow apart precisely because it is designed to handle the high pressure involved. True, that pressure is dropping more slowly than would be the case if the bullet were moving, but the gun will take it.

Hatcher, in fact, did the experiment with a Model 1903 rifle. He blocked the barrel with welded in steel rod. The gun was hung on wires, instrumented, and fired remotely. It never moved. After a few minutes, they hammered the bolt open and it flew back with a loud bang from the pressure still in the chamber.

As to what causes barrel bursting, I believe it is not gas pressure or a pressure wave. Rather it is the kinetic energy (all those foot pounds) which suddenly are converted into heat and have to go somewhere. A slow moving bullet (.38 S&W say) can be stopped with little damage, but the higher the energy the greater the damage that will be done.

The conversion of kinetic energy into heat is well known. It is what causes .22 bullets to melt when they strike a steel plate or a rock. It is also what causes those "splashes" in steel that is struck by a high speed bullet. In fact, it is what allows armor piercing ammo to work - the bullet energy is converted to heat and melts the steel so the AP core can penetrate.

You can e-mail me at keenanj@xecu.net. This could be interesting.

Jim