Secrets of the Mystery Gun that Shelled Paris (Jun, 1930)

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Secrets of the Mystery Gun that Shelled Paris


Chief Artillery Engineer, A.E.F.

The secrets of the Paris Gun! For the first time in any magazine, Modern Mechanics here reveals the inside facts concerning the most startling and closely-guarded mystery of the World war—the official story of the giant German guns which, in 1918, dropped shells on Paris from a distance of 75 miles, a feat so incredible that artillery experts refused to believe it possible, thinking for a time that the shells were bombs dropped by high-flying aircraft. After the war the guns were destroyed and all information concerning them locked in secret archives. It was declared high treason, punishable by death, for anyone who possessed vital information concerning the guns ever to divulge it. Nevertheless, Col. Miller, author of this article and of the gripping book, “The Paris Gun,” obtained military pictures and technical secrets from confidential German sources which has enabled him to reveal to Modern Mechanics’ readers the astonishing story of the longest range guns the world has ever known.

ON THE morning of Saturday, March 23, 1918, as all the world knows, a supposed air bomb dropped into a Paris street and, when the fragments had cooled enough to be picked up} it was discovered they were marked with the lands and grooves of rifling, something no air bomb ever possessed.

By the time five or six more had crashed down, at intervals averaging about 15 minutes, the French artillery department had definitely decided Germany had accomplished the impossible and was shelling Paris with a gun that must be at least seventy, and probably seventy-five miles

away. What that meant may be visualized by recalling that the longest land bombardment in previous history occurred in 1915 when the Germans shelled Dunkirk from a distance of 23V-J miles with a 15-inch naval gun mounted on a railway truck.

Twenty-five shells dropped into or near Paris on that March Saturday, killing sixteen and wounding twenty-nine people.

The long range gun, or rather guns, for there were seven of them built, in all, and six were actually used at the front, remained one of the war’s greatest mysteries for years after the armistice, guarded by the death penalty for anyone caught revealing it. No gun was ever found in place, but we did find an almost complete emplacement in France, abandoned when the Germans retreated too fast to destroy it, and we did find an almost complete gun in Belgium, and the measurements of the two coincided. Long after the armistice 1 learned that our artillery destroyed the railroad junction at Soissons just two hours too late to catch the last of the guns as it was retreating.

But, while the guns remained a mystery, their location did not, for within two or three hours after the first shell fell, artillery experts had figured out where the monsters must be located. An aerial photograph of that district, taken on the previous March 6th, showed two railway spurs which must have been used to place them, and within a short time sound-ranging apparatus at the front had confirmed the diagnosis by identifying the sound as they fired. All that was done before dusk that Saturday, despite elaborate camouflage arrangements that even included trees with six-inch trunks set in slots in the railway line at 30-foot intervals to hide even the tracks to the gun from aerial observers.

Now that the rest of the story can be told, consider the guns themselves: There was a barrel 120 feet in length, approximately twice as long as the biggest guns built to that time—so long, in fact, that the end had to be supported in the air to keep it from bending down and being shot off by its own shell. In fact, that very thing happened to the first of the guns tested at the German proving ground, for the barrel bent a full inch under its own weight.

Next they fired a shell 75 to 80 miles or more, over a total trajectory ranging from 90 to nearly 100 miles.

To do that the shell was shot 24 miles above the earth, higher than any man-made thing, save possibly a small sounding balloon, had ever penetrated. At that extreme height the shell traveled through what was almost a vacuum, at a temperature of far more than 100 degrees below zero.

The shell, traveling at an average speed of 30 miles a minute—or sixty times as fast as the usual legal rate for automobiles — took three minutes to complete its aerial flight of 90 miles. It remained away from the earth so long, in fact, that the old world revolved on in space while the projectile was away, so the gunners had to aim a half mile east of the target in order that the target might be there when the shell arrived to hit it.

And, finally, the Paris gun, as I have called it, was the first ever built that contained within itself a device that told where I he shell had landed—in fact, the gunners could tell where the shell hit before it had actually hit there.

And to that might be added one other thing—the fact that the speed with which the Allied artillery chiefs located the guns and took steps to silence them defeated their main object, that of stampeding the people and scaring them half to death by the mystery of the thing. For the mystery, as has been said, didn’t last through the first morning.

The long range guns, it might be well to explain, should not be called “Big Berthas.” The “Big Bertha,” named for a fancied resemblance to the matronly figure of Frau Bertha Krupp, was a short, squat, wide barreled seige mortar, a seventeen -inch piece with which the Germans reduced the stone and steel fortifications of Liege in the first weeks of the war.

The long range guns were the conception of Dr. Von Eberhardt, a German physicist, who, early in 1916, with his chief, Dr. Rausenberger, convinced General Ludendorff that a cannon with a sixty-mile range could be built. Work was started, but at the end of the year there came a sud- den wire from the front ordering the range to be increased to seventy-five miles. The German high command had decided to retreat the next spring from the Somme to the Hindenburg line, and a sixty-mile gun would no longer be within range of Paris. To build the giants the Krupp factory took 15-inch, 45 calibre naval rifles, with railroad mounts, reduced the bore to 8.26 inches and just about doubled the length by shrinking into it the end of a 98-foot long rifled tube. That was the plan for the original 60-mile gun, and it had been built when the order came to increase the range to 75 miles.

No one had ever succeeded in joining two rifled tubes together and keeping them in alignment, and there was no boring mill in Germany big enough to bore a barrel twenty feet longer—the extra length needed to increase the range. For every millimeter added to a gun’s length the projectile will go three meters farther, and it figured out that twenty more feet of barrel would turn the trick. So the Germans decided the rifling in the 98-foot tube was sufficient to start the shell revolving and keep it from wobbling in the air, and, therefore, the extra twenty feet could be smooth bore tube, and that is how they did the job.

By the summer of 1917 the work was far enough along, it was believed, to order the emplacements built for the first three guns. They were to be placed in what was known as the Laon corner, a salient which enclosed the forest of St. Gobain, and was the nearest approach of the Hindenburg line to Paris.

The guns had been built, but then a hitch developed, for every shell tried was a complete failure. It was not until the following January that a shell was designed which proved saisfactory, and it was this shell that was used on Paris in March.

Ordinary cannon projectiles are smooth steel cylinders fitted with copper “driving bands.” As the shell passes through the rifled barrel the soft copper is engraved in grooves by the rifling, imparting the twisting motion which keeps the projectile from wobbling while in flight. The copper bands also act as piston rings to keep the gas from escaping from behind the shell.

But with a pressure twice as great as anything used theretofore the copper bands were sheared off the long range shells. Finally the German engineers created shells with rifling grooved in the steel walls, and copper bands behind the rifles to keep the gases in place. The shells were screwed into the barrel rifles at the breech and when fired, the rifles, with 4-degree pitch, started the projectiles spinning at 107 revolutions a second when they left the rifled portion of the barrel.

The shell had an enormously thick base and lower side walls to withstand the tremendous pressure of a million pounds. It was fitted with two fuses, to lessen the chance of failure to explode — and in fact not a single one did fail. The load was eighteen pounds of T.N.T. After it was shoved up and twisted into place in the rifled barrel two silk bags and one brass cartridge case of powder were inserted in the I breech, a total I of 431 pounds of powder for the initial charge in a new gun.

The firing table for the gun was one of the weirdest wonders ever conceived in bal listics. It took into consideration the state of the gun bore, the wind direction, velocity, barometric pressure, and even the compass bearing of the target, to allow for the turning of the world. The gun was fired at only one elevation—55 degrees—and the range “was corrected by changing the powder •charge. Another addition had to be made to each powder charge to compensate for the wearing of the barrel during the previous shot. The powder chamber of a gun is bored larger than the rifled portion of the barrel, and where the two meet the chamber is tapered down to barrel size in what is called the pressure cone. Each time the gun is fired tiny bits of the cone are •eroded, so each following shell slips a little farther up the barrel, and thus shortens the useful barrel length.

How the Gun Wore Out Cone wear of a fraction of a calibre up to one calibre is usually considered sufficient to warrant sending the gun back to be rebored. (A calibre is the diameter of the shell, thus a 6-inch gun of 50 calibres length has a 25-foot barrel.) But in the German guns cone wear progressed up to six feet of barrel length before they were discarded. This excessive wear explains the fact that shells fired at Paris the first day traveled ^n average of three miles farther than the ones fired the second day.

The muzzle velocity—practically a mile a second—was the highest ever reached in a big gun. The shell started out at 5500 feet a second; had dropped to 3300 feet by the time it had climbed to twelve miles, and was down to 2200 feet at the height of its trajectory, 24 miles in the air. But more than three-fourths of the total trajectory was up in the rarefied air, where resistance was practically nil, which explains the extreme range attained. When gravity began to pull the shell nose down toward earth the velocity climbed again to 3300 feet, but as it continued to fall it actually lost speed, due to air resistance, and was not traveling more than 2450 feet a second when it hit Paris. The initial energy when the shell left the muzzle, by the way, reached the enormous total of 8 billion foot pounds. (9,000,000 h.p.w.) I mentioned some paragraphs back that the gun contained a device to tell the gunners where the shell hit, even before it had hit. This was a pair of pressure recorders, set into the breech, to measure the gas pressure at the moment of discharge. German powder varied so much in quality the last year of the war that the muzzle velocity differed as much as 100 yards for various discharges, so the gunners never knew until after the shell was on its way where it was going. But as soon as they had the pressure figure they could tell from their tables where it would arrive.

Despite all these handicaps it is interesting that of the 25 shells fired the first day, 12 landed within a two mile circle. Two, however, were more than eight miles apart, both falling outside of the city walls on opposite sides of Paris.

¦ To take up the shock of the recoil when a million pounds of pressure started pushing a shell up the 120-foot steel tube required an enormous emplacement. In the later installations a pit eight feet deep and forty feet across was dug. On the bottom heavy “I” beams, arranged in a radial pattern, were laid, and on these a doughnut shaped steel caisson was assembled, with manholes in the tops through which it could be packed tight with sand bags. The turn table, key plates and the mount for the railroad gun carriage were built up on these, with a track down the center for the railway car. On either side additional railroad tracks carried a gantry crane of 175 tons capacity to handle the gun barrel.

When all was ready the railway trucks of the gantry crane were unloaded from their car on ramps provided for the purpose, and on them the gantry legs were set up and bolted down. Each gantry leg was topped by a jig crane, and with these the cross beam of the gantry was hoisted into place. Next the gun carriage, on its own wheels, was rolled onto the revolving turntable-like center section of the mount, a turn table that revolved on 96 steel balls 8 inches in diameter. Four powerful hydraulic jacks lifted up the carriage while the railway trucks were detached and rolled out of the way, then lowered it into place and it was secured to the turn table.

The gantry then picked up the 150 ton gun and swung it into place over the carriage. It took two weeks or more to prepare the emplacement and mount the gun.

Because of the complicated firing data, and the natural dispersement of the shots due to the extreme range, gun wear, wind drift, poor powder and other causes, only one target was ever used. That was the geographical center of Paris, a spot at the east end of the Palais de Louvre.

It is interesting that within an hour and a half after the first shell fell Allied officers had not only calculated the location of the gun but estimated the target on which it was laid probably was the “zero point” in Paris, the exact center of the Place in front of the Cathedral of Notre Dame, on the Isle de la Cite, in the Seine. The distance between the geographical center and the zero point is about one-half mile.

The location of the gun and the probable target were both calculated by charting the first seven shell bursts and drawing a line along the center on which they seemed to he falling. It is a curious thing that a number of shells fired from the same gun at the same target usually will be so equally spaced that if you draw a rectangle around all the bursts, and divide it with eight vertical and eight horizontal lines, 25 per cent of the shells will be found to have fallen within the first spaces on either side of the center lines, either up and down or across; 16 per cent in the next spaces; seven in die next and two per cent in the outer ones.

After the war when it became possible to talk to German officers, view the ground and consult German records we found just how effective the counter activity of the Allied artillery and aerial observers had been.

Five German long range guns were used at the St. Gobain woods position. One gun had burst while being fired and killed its own crew. Two positions, within the first week, had been shelled until they could no longer be occupied. A third was practically untenable when orders came to abandon it. The fifth gun fired just 64 shots before it was worn out. In five weeks 5,000 French heavy caliber shells fell on and around the gun emplacements. Toward the end they dropped as fast as 100 shells an hour. And in that five weeks the five German guns had fired just 183 shells in and around Paris!

  1. Tom Bates says: October 9, 20083:24 pm

    HI, can you post the story about the diveing plane carrier? I would greatly appreate it. Thanks

  2. Torgo says: October 9, 20089:08 pm

    What a great, technical article. And it is interesting that this is the guy who, apparently, named the gun “The Paris Gun” which is what it is still called today.

  3. pollywog says: October 29, 200811:26 am

    Amazing technical achievment – but at a horrific cost. The war was virtually lost yet all these resources were literally thrown away by the Germans at the cost of their people. The same would happen again 25 yrs later!

  4. jayessell says: October 29, 200812:58 pm

    Pollywog… Do you mean the V2?
    The time, money, resources and yes, slaves, used to make the V2 was thankfully wasted.
    More V2s meant fewer guns, tanks and bombers which would have killed more people than the V2s did.
    Has anyone calculated the number of people killed by V2 attack vs. the number killed in V2 manufacture?

    PS: Double agents lied about the impact sites in Britain, making the launch crews put the wrong numbers into the guidance system!
    (Or was that the V1?)

  5. mickey says: May 18, 20098:34 am

    while a weapon of that size and design would be horrible in terms of practicality and resources, it was a very important tool in terms of propaganda. would you want to fight a country that had a gun that could fire shells directly into your capital from over 60 miles away?

  6. -DOUG- says: May 19, 20094:31 am

    The Paris Gun, known during the war as a “Big Bertha” after Bertha Krupp. Of course after the war the expression was limited to the Howitzer, dubbed this by the Germans to HONOR Bertha Krupp and not to mock her, and the larger pieces were given unique names. The Paris Gun, also known as the Emperor William Gun, is yet another chapter in the two histories I love so much: The history that happened, and the history that people THINK happened.

    I’d never seen this article, but I knew there was a debunked “Expert,” I suppose this is the man. The Paris Gun barrel is regarded as being almost 90 feet, not 120 feet, and no “Near complete gun” was ever captured, only a mounting which was generic to a number of the railroad car guns and believed to be of the type that the Paris Gun used. The experts can’t even say for sure. Of course I’m only saying that from having read about it, while this man is renowned for having NOT read. Nothing existed for him to read. But since noone else knew anything about it between the two world wars, no argument could be offered the man, and he got a lot of mileage out of his Paul Bunyanesque tale.

    “. . . .the first ever built that contained within itself a device that told where I he shell had landed—in fact, the gunners could tell where the shell hit before it had actually hit there.” Oh please. But it speaks volumes, the man was strictly a crowd pleaser. Certainly that was one of his many passages of vicarious thrill and wonder offered to the unknowing public of the day.

    What is certain is that while the German battleships of the time mounted only a 12 inch gun, it was more effective than the heavier 14 inch guns on the British battlecruisers, which sported less armor than full battleships with smaller guns to help them keep from lumbering slowly behind. Such guns as the 15 inch Langer Max were also used on railroad cars, (Operated by the Navy, commanded by Admirals) and in fact were firing larger shells than the Paris Gun, which started out at about 8 inches. As the article mentioned, the wear factor for a single firing was incredible, and multiple size rounds were carried and the barrel opening regularly measured to ensure they knew just when to step up to the next size. But the barrel wasn’t discarded when it got too large, it was returned to the factory and bored out larger. It would eventually fire a nearly 10 inch shell.

    It was the sheer length of the Paris Gun that set it apart, and made it capable of firing a shell some 25 miles into the air to land up to 75 miles away. The inaccuracy at that range was attributed to the Coriolis Effect, the revolution of the Earth itself. The Germans had figured that out, and were trying to compensate.

    I hate to argue with his article, but then so many already have. He gives half the number of shells fired as the official estimate of as many as 367. He says 25 shells in one day, officially it never exceeded 20. He mentions multiple guns firing, those would be the “Noise Screen,” firing away as a distraction to make it difficult to find the real gun, not additional Paris Guns. Only one is known to have existed, not the 7 the author claims. But there were many railroad guns in use by the Germans. Brunos fell in the hands of the Belgians after the war, and at the beginning of WWII fired at the Germans, who fired back with other Brunos. One Thedor Otto was captured by the Allies, the others disappeared, as did the Paris Gun.

    Although much is known about most of the German railroad car and heavy siege guns, the Paris Gun eluded not just capture and inspection by the Allies, but even mention in any records The Germans are believed to have destroyed it near the end of the war to prevent its’ capture, but what were they using in firing tests at the time of this article as a preliminary to developing rockets? This was further studying the Coriolis Effect that had made it impossible for them to, as the author pretended, “. . . .so equally spaced.”

    Ah, but maybe they were firing prototypes for the next generation of guns. While leftover railroad car guns found their way into the Second World War, the Germans did develop the Schwerer Gustav, firing a 31 inch shell through a longer barrel but at shorter range; and the V3 Cannon with a range of over 100 miles that was intended to shell England from France. For all the fears that the Paris Gun would reemerge, Gernany had new weapons that were far worse.

    But what of this Colonel Henry Miller? Did he exist? Could he have been part of a disinformation campaign by the American military as they tried to SEEM as though they were on top of things, even as they fell farther and farther behind other countries?

    Or could he have been an example of the mendacity of former soldiers after a war? The greatest example of this could be the aftermath of the American Civil War, when exConfederate soldiers traveled the country telling their versions of the war, which could change from night to night to please the differing crowds.

    Possibly the most successful post war fictionaire would Mitso Fuchida, the Japanese pilot who spoke the words ‘Tora Tora Tora’ at the bombing of Pearl Harbor. Or at least he SAYS he did, there were no survivors to confirm it. He burst on the scene in the early 1950’s with his romanticized account of the Battle of Midway from the point of view of a star crossed Japanese navy. From stooge senior officers who wouldn’t listen to his dire warnings to technology the Japanese never had, his confirmation of American theories about the Japanese navy were readily available — for a price. Meanwhile, it was the stooge American military historians who wouldn’t listen to the other Japanese survivors who warned that he was feeding them fiction. But why would they listen? He was saying what they wanted to hear.

    So was Colonel Miller another Mitso Fuchida, or was he perhaps another Dr. Thomas Dooley? Navy doctor Dooley, in fact, played a huge role in getting the United States into the Vietnam war. His three books of his late 1950’s experiences in the various ‘Domino Effect’ countries, written at the prodding of the CIA, would greatly sway Americans in opposition of allowing Communist rule. The resulting work is largely fiction, depicting a Christian majority oppressed by the Communists when in fact Christians were few and far between in Asia, and fantasizing such colorful events as ‘The Night they Burned the Mountain’ that are in fact known to have never occurred. And yet Dr. Dooley, forced from the Navy for ‘Conduct Unbecoming,’ inspired John F. Kennedy to create the Peace Corps, and the Catholic Church is known to have considered canonizing him as a saint. All for acting as a spokesman for the shadowy world of disinformation.

    Ah, but between the fog of war, and the greater fog of postwar, we’ll never know. There’s a highly regarded book on the Paris Gun by Gerald Bull, the renegade scientist who used his knowledge from the joint US-Canadian High Altitude Research Program to design the Iragi Babylon gun that couldn’t be built after his assassination. An assassination that both the Israeli’s and Iranians seek to take credit for. The British claimed to have seized the barrels for the gun that were built in Europe even as the Iraqi’s claimed they were oil pipes. At the time of the Gulf War, the stories were reversed as the British said they were oil pipes and sought the real barrels while the Iraqis said no no, they were right the first time when they said they had the barrels. Regardless of the truth, you’ll hear the version that suits the side that tells it. And much will be told of every version.

    And strangely, it well suited both sides to depict the Paris Gun as a miracle weapon: The Germans so they could take credit for building it and the Allies for their fortitude in withstanding it. Instead it was sort of the Scud missile of World War I, feared not so much for its’ power to wage war as the fact that it would lash out as a random act of fate, causing many a soldier and civilian to lose sleep. Far more scary than the idea they could hit the target they were aiming at was the idea that they might hit everything else but.

    And the big question here: Colonel Henry Miller, real or imagined? Fool or tool? The possibilities range from his being a creation of the editors of ‘Modern Mechanics’ as they planned their article, or a real artillery officer reporting what they U.S. military THOUGHT they knew about the Paris Gun. We’ll never know, but at least we’ve learned not to fall for hype about weapons of mass destruction.

    Haven’t we?

    (Big guns or no, it’s late, I’m going to bed.)

  7. Firebrand38 says: June 4, 20094:19 pm

    Miller also wrote a book on the subject which is available to read online…

    Since the TOC is arranged by paragraph numbers I’ll just tell you that the chapter on the Paris Gun is on book page 723.

  8. -DOUG- says: June 4, 20098:55 pm

    Hey, thanks. I get a much better feeling about Miller in that. In fact, it makes me consider that the guy submits one article, and the editors decide to ‘Fix’ it for him. Meaning give it a much more salacious sound. Notice how much in the report is qualified as ‘Hearsay’ and other admissions that it’s speculative, while the article makes it sound like accepted fact. Whether Miller himself decided to pander to the wide eyed public in retirement or heaved a sigh when he saw the ‘Improvements’ we’ll never know, but I guess I can see he was the real thing.

    It’s just so amazing to see the efforts to reconstruct this weapon without seeing it, without seeing any technical publications about it, even without real cooperation.

    But note that even in the report he’s saying all the gun did was make the Allies want to fight back. The propaganda battle never ends.

  9. Firebrand38 says: June 4, 200910:23 pm

    In a 1948 Field Artillery Journal they printed some photos of the Paris Gun firing…

  10. -DOUG- says: June 5, 200912:03 am

    Can’t get that “.PDF to open, but after WWII pictures got to floating around. Even the Krupp family started passing them out. A lot was learned about it once the psychological issue didn’t matter anymore.

    I put the Paris Gun up there with the battleship Tirpitz in WWII, for the distraction it created. Look at the resources the Allies tied up trying to get at that big gun, and then in going after a crippled battleship that wasn’t much capable of putting to sea. If there had been an effective way to use these assets. . . . Well, luckily for our side, they couldn’t figure out how. (Assuming noone is from Germany, here.) Think of the further forces brought to bear against them if they HAD become effective.

  11. happyseaurchin says: August 16, 20099:37 am

    thanks for the article
    and i found doug’s magnus opus a really interesting read
    considering i don’t follow war or it’s history much…
    send us a link to your interesting stuff doug 🙂

  12. -DOUG- says: August 16, 20093:50 pm

    Dang, that was a landmark case in value of proofreading, wasn’t it? I’m one of those people who looks it over and sees what I intended to write and I don’t catch that I left words out, etc. I guess it’s still readable.

  13. fii says: August 17, 20094:28 am

    Doug, you’ll never see this, but your comment was the best I’ve ever seen on a blog I think.

  14. Firebrand38 says: August 17, 20093:11 pm

    Isn’t this cozy? Why don’t you two room together next semester?

  15. -DOUG- says: August 18, 20093:42 am


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