THE DEVELOPMENT OF THE THOMPSON SUBMACHINE GUN
Theodore H. Eickhoff
General John T. Thompson, then “Colonel Thompson”, was stationed in the Office of the Chief of Ordnance in Washington D.C. when I graduated in June 1908 from Purdue University. After passing a Civil Service Examination, I entered upon a position of Electrical
and Mechanical Draftsman in the Office of the Chief of Ordnance in
September of that year. Colonel Thompson was in charge of the Small Arms and Equipment Division; my assignment was in the Artillery Division. The following year Col. Thompson requested the transfer to his division of a draftsman whom he could use to undertake a study of the then-existing automatic rifles being developed in the United States and abroad, and to study all military rifles used by the Nations of the world. Upon my volunteering for the transfer I was assigned to the Small Arms and Equipment Division. This was the beginning of my association with Col. Thompson.
At that time there was a keen competition between the Colt’s
Patent Firearms Mfg. Co. with their caliber .45 Browning Automatic
Pistol, and The Savage Arms Co. with their caliber .45 Savage Auto-
Matic Pistol, to get their respective pistols adopted by the army as
the standard side arm. Previous competitive tests had eliminated all
other automatic pistols submitted for test, leaving Colts and Savage
alone in the field. However, in those previous competitive tests,
both pistols fired caliber .38 cartridges; now they were to submit
pistols firing a newly adopted caliber .45 cartridge.
This change in cartridges had a bit of interesting history.
During the Spanish-American war, when fighting the Moros in the Philippine Islands, the stamina of these natives was such that the caliber .38 revolver bullet would not stop them; they came rushing on our men charging with their bolos. Up to that time, the
Caliber .38 revolver had been the standard side arm of the army. A
heavier bullet was demanded by the army, and was developed by the Ordnance Department. Col. Thompson had been a member of the Board of Officers in the competitive test of automatic pistols, and also a member of the Board of Officers testing the new caliber .45
cartridge with it’s 230-grain, cupro-nickle jacketed, blunt-nosed,
lead-cored bullet. Among other tests of the bullet that were made,
leading up to the adoption of the caliber .45 pistol cartridge, was
a study of its stopping power by firing the bullet into live animal
tissue at the time of slaughter. About the best description of the
stopping power of this new bullet was given by the man who had been accidentally shot in the shoulder; he said, it felt as though about a dozen men had rammed him with a telephone pole carried on their shoulders.
Each of the contestants, the Colt Company and the Savage Arms Company submitted caliber .45 automatic pistols to the Ordnance Office for preliminary tests. They were fired at a near-by rifle range until a “bug” developed. I was assigned to witness these
tests, keep a record, and make a report thereon. Further development refinements were made by the respective companies and the pistols resubmitted. Ultimately endurance firing reached a point where it was considered the pistols were ready for a final official competitive test.
Each company delivered a pistol to the Ordnance Office, and I
was given the assignment to travel to Springfield, Massachusetts,
and personally deliver these two automatic pistols to the Commanding Officer of the Springfield Armory for a final competitive test. In this test the Colt Browning Pistol won out and in 1911 the Colt Browning caliber .45 Automatic Pistol was approved by the then
Secretary of War, William Howard Taft, as the standard side arm for
Shortly after I entered the Ordnance Office the Wright Brothers
made the first public demonstration of their “heavier than air”
flying machine. The demonstration took place at the Ft. Myer
Cavalry Drill Grounds, across the Potomac River from Washington. It
was my privilege to attend that notable event. All foreign military
attaches stationed in Washington, were out in their full military
regalia. It was a very festive, clear autumn day. At the end of
the field a fly tent had been erected to serve as a grand stand for
the chief observer, the Secretary of war, William Howard Taft. At
the appointed time the Wright plane was launched from a specially
built platform, erected for the purpose. The flying machine
consisted of two horizontal canvas planes held together by a light
framework extending to the rear to support vertical and horizontal
control vanes. The engine was mounted between the planes on the
framework, and the operator, Mr. Wright, sat next to the engine.
The fans were driven by link-chains. The plane rested on light
skids like that of a sled.
On the take-off an impetus was given to the airplane by the release of a heavy weight which fell to the ground, which, with a
rope guided over pulleys, had been hooked to the front of the
airplane frame, and at the end of the sloping ramp was automatically
detached. With the engine running, driving the fans, the plane slid
down the 30-foot ramp, skidded on the ground a bit, gradually gained altitude, and made about a dozen laps around the drill field at an altitude of about 50 feet and then landed safely on its skids.
During the flight the operator could be well observed; a girl
shrieked “Oh look, he is wearing tan shoes”. The afternoon’s
performance was a grand success, and all the world knew that man
could fly in a heavier than air machine.
In those days congressional appropriation for development work were very meager. World War I broke out in 1914, and France and Germany battled in the air with air planes. The congressional
appropriations for the development of air planes here at home, up
to the time of our entry into the conflict in 1917, had amounted
to only a few hundred thousand dollars as General Pershing relates
in his book on World War I. When we ultimately got into production
of arms and equipment for the war, 600 million dollars were
appropriated for air planes, but, as General Pershing points out,
no American-built plane ever reached the fighting front.
Incidentally, as a matter of historical interest only, the
following year I joined some officer companions for a boat trip down
the Chesapeake Bay to Norfolk, Virginia, to witness the homecoming
ceremonies of the U.S. Battle Fleet, at Hampton Roads, which had
been sent around the globe by President Theodore Roosevelt.
Not long after the beginning of World War I, Colonel Thompson
retired from the army and accepted a position as Consulting Engineer
with the Remington Arms Company which had built a new plant
Eddystone, Pennsylvania, for the manufacture of Enfield Rifles for
the British. Sometime later, I found myself resigned my position to try
my hand in the commercial or industrial fields.
In the summer of 1916, Col. Thompson sent me a telegram to
come to Chester, Pennsylvania and meet him at the railway station.
At the appointed time, I made my appearance there, dressed in my
Best and wearing a stiff hat, which was popular in those days. To
receive a request from an Army Colonel, to meet him for a interview,
was an unusual and great experience and I put on my very best manners.
Col. Thompson was at the railway station when the train arrived;
and, after a cordial greeting of old time friends, we stepped into
a Winston-six, which was the finest in that era, and a chauffer drove
us through the country-side to the Colonel’s country home near
Those were the days of the dying chestnuts. On the train to
Chester I had noticed innumerable dead tree trunks among the beauti-
fully green hillsides; and now driving in an auto through the
countryside, those dead tree trunks were more pronounced. In the
yard of the Colonel’s home there were about eight huge stumps which
were all that was left of a grove of stately chestnut trees. Upon
inquiry I was informed that all those dead trees I had seen were the
result of the chestnut blight. That was the first time I had heard
about the chestnut blight, and saw first hand what a terrible
devastation it produced. Only a few years later this awful disease
ravaged Ohio also.
During our drive to Media, the Colonel explained that the real
reason for his retiring from the Army was to attempt to get private
capital interested in the development of an automatic should
rifle for the Army; that congressional appropriations for this
purpose were next to impossible. The acceptance of a position as
consulting engineer for the Remington Arms Co. in the manufacture
of the Lee-Enfield rifles was merely incidental. He seemed quite
exhuberant about progress in the manufacture of the rifles and was
particularly elated about the production of barrels which had just
been brought up to 200 per day. “Barrels” seemed to be uppermost
in his mind and his mind was saturated with “barrel making.” I,
on the other hand, had during the previous autumn he ped my mother at home operate a customs cider mill where the neighboring farmers and orchardists bring their apples to have cider made. One of the headaches of this operation was to provide an empty supply of
“barrels” to contain the cider. My mind was still saturated with
“cider barrels.” Somehow my mind was slow in orienting itself from
cider making to rifle making, and with the Colonel’s frequent
reference to “barrels” I was just about to ask him as to where all
those barrels were being used. But fortunately, before asking the
question, a quiet voice within me said, “ why you dumb-bell, wake up;
orient yourself and be quick about it; he is manufacturing rifles,
and obviously he is talking about ‘rifle barrels’ ”.
In the quiet of his home, Col. Thompson related that his great
Ambition was to develop an automatic shoulder rifle for the Army,
Within the prescribed limits of weight. He had searched the
Existing patents and had found the Blish patent which, he was
Confident, could produce the satisfactory automatic breech action
within the weight limit, and he felt confident of financial backing
which he was presently negotiating, and was now ready to engage an engineer to undertake the development work. He offered me the job of designing and engineering an automatic shoulder rifle. He
explained that he had learned that I had left the Ordnance Office
and felt free to make me this offer. As I had made no permanent
connections since resigning from the Ordnance Office, I willingly
accepted. After closing up activities I was engaged in, I
presented myself within a few days to begin the activities of
developing an automatic shoulder rifle.
Col. Thompson arranged that I make my living quarters with the family and carry on the design work in a room provided for the
purpose. I studied the Blish patent and we fires a few shots from
a pistol that Commander Blish had made, based on his patent.
Commander Blish had been stationed on a battleship on which
The heavy guns had been fired numerous times, with full charges,
without any mishap. On one occasion, however, during target
Practice, while firing reduced charges, the breech block, of the
Interrupted screw-thread type, opened, resulting in some casualties
among the gun crew. Commander Blish offered the explanation for
this mishap that at the high pressure of a full charge the breech
was immovably locked, by a “super-friction”, or an “adhesion,”
while at the lower pressure of a reduced charge such “adhesion”
did not exist; consequently, the breech unlocked on the inclined
angle of the screw thread. He foresaw the possibility of building
an automatic gun on this principle, applied for a patent and was
granted Patent No. 1,131,319 dated March 9, 1915. It was on the
basis of this patent that we undertook the design of an automatic
Col. Thompson readily agreed to the suggestion that we first
design and build a testing apparatus or “Trial Mechanism” with which
to try out the principle, study the action and make determinations.
When the design was completed he asked the Warner & Swasey Company of Cleveland, Ohio, to make this mechanism for us. He was personally acquainted with Messrs. Warner, Swasey and F.A. Scott, in fact he was on very friendly terms with them. The Colonel had very great confidence in the company to produce only the highest quality of workmanship, and he wanted the mechanism to be of the highest quality.
In due course of time, the mechanism was ready for testing; and I was sent to Cleveland to initiate the tests. I made two or three
prolonged visits to Cleveland and soon became permanently stationed in Cleveland. The mechanism gave promise of functioning, but tests always led to changes and improvements. After a long series of tedious and exasperating tests we discovered that the
difference between satisfactory functioning of the mechanism, and
non-functioning, was a matter of a slight lubrication on the
caliber .30 rifle cartridge we were using. This was the standard
U.S. Army rifle cartridge. After knowing this and applying a very
slight lubrication to all cartridges, we could produce satisfactory,
reliable functioning indefinitely.
Now to get a picture of this organization of the Auto-Ordnance
Corporation, we will go back to when I first came to Chester to
meet Col. Thompson.
The Colonel’s family consisted of Mrs. Thompson and one son, named Marcellus, who at that time was a Major in the Artillery Unit
of the Army. He had only recently married the only daughter
of Col. George Harvey who had been U.S. Ambassador to the
Court of St. James and was editor of the North American
Magazine. Whether the Thompson family and the Harvey family
were friends before the marriage of their children or was as a
result of the marriage I never learned. Col. Harvey was a
close friend, and I think, an advisor to the New York
financier Thomas Fortune Ryan; and it was apparently through
the good offices of Col. Harvey that Col. Thompson succeeded
to get Mr. Ryan interested in his venture to develop an
automatic shoulder rifle and to back up the venture financially.
Soon after I was started on the work the organization of
the Auto-Ordnance Corporation was accomplished. Col Thompson
discussed with me the choice of a company name which was
ultimately agreed upon as “Auto-Ordnance Corporation.” It
was arranged that all my work was to be carried on in utmost
secrecy. I was not even to reveal the name of the company,
but to transact all business in my own name. My salary was
paid monthly by Mr. H.H. Vreeland, Mr. Ryan’s Office Manager
at his New York office. I was to make frequent reports of
progress to Col. Thompson and to make a monthly report of
expenditures. with a request for funds for the coming month,
to Mr. Vreeland.
At about the time when I was worked continuously at Cleve-
Land, the U.S. entered into W.W. I. Col. Thompson was
called back into Military Service as a Brigadier General.
At Cleveland, I had established my own office at 5716 Euclid
Ave., not far from the Warner & Swasey Company; and was
adding personnel to the office. The Warner & Swasey Company
became very busy with war work and urged us to “farm out”
what machining had to be done to various small machine
shops. Ultimately we acquired a few essential machines
and operated our own machine shop.
Some time later a young man by the name of Oscar V.
Payne, who had been doing Patent office work, applied to
General Thompson for a position in the Ordnance Office
for Automatic rifle design work. General Thompson referred
Mr. Payne to me and we arranged to have him come to
Cleveland for an interview, with the results that he
was added to our staff. He proved to have a remarkable ability to
take an assignment, brood over it for several days, and come up
with alternative proposals carefully giving all the “pros” and “cons”
for each so that the making of a decision for proceeding was very simple. In addition he was an excellent artist who could reduce
his ideas to clear, simple sketches readily understandable.
While living with the Colonel before coming to Cleveland I got
well acquainted with the Colonel’s chauffer, George Goll. He
hailed from Bangor, Pennsylvania, of Pennsylvania Dutch stock, a
very likeable young man. He was cheerful and always saw the funny
side of things. He would have been a success as a comedian on the
stage, on radio or television. After we got acquainted he confided
that when he first saw me at the railway station at Chester,
Pennsylvania, he felt sure that his was the honor to be driving the
Colonel with the Secretary of War as guest. In course of time he
was drafted into military service and upon his release after the
armistice, he joined our organization at Cleveland. He had the
remarkable ability and tenacity, if any mechanism was not working
well, to check all parts against the drawings and find where any
dimension was slightly off.
When the group at Cleveland became convinced that the caliber .30 Army rifle cartridge defiantly would not function with the
Blish automatic bolt action without lubrication, I made a personal
report thereon to the now “General” Thompson. But prior to making
that report we had made a careful study of all types of cartridges
and had developed what we called the “coefficient of ejection” for
all the popular makes of cartridges. This coefficient was nothing
more than the ratio of the effective thrust area of the chamber
powder pressure against the bolt, versus the area of the cartridge
case pressing against the chamber by the inflation of the cartridge
case under the high chamber pressure. In simple words, it was the
quotient obtained by dividing the area of the mouth of the cartridge
case by the exterior surface area of the cartridge case contacting
The U.S. caliber .30 rifle cartridge that we were using had the
poorest coefficient of .025; whereas the caliber .45 pistol ball
cartridge, used in the recently adopted Automatic Pistol. Model of
1911, had the highest coefficient of .150. This is the cartridge
that I had seen used so much in testing automatic pistols while in
the Ordnance Office years before, and I felt quite partial to this
We had also, before reporting to General Thompson, made
extensive tests with the caliber .30 rifle cartridge by coating
them with various kinds of waxes and found that a wax coating on
the cartridge case answered all requirements of lubricating the
cartridge case. These waxed cartridges functioned reliably and
dependably in the test mechanisms. Our thought was that in the
manufacture of cartridges a simple waxing operation could be added
and all cartridges be waxed.
When I personally reported to General Thompson that the caliber .30 rifle cartridge defiantly would not function with the Blish
bolt action in the dry state, but that a slight lubrication on the
cartridge case was required to obtain reliable and dependable action, he did not seem greatly surprised but seemed to have anticipated such a verdict, having kept in close touch with our progress by
almost daily reports and frequent telephone calls. Then I explained
the “coefficient of ejection” to him and pointed out that the
caliber .30 cartridge we were working with had the poorest
coefficient, while the caliber .45 pistol ball cartridge had the
highest coefficient; and recommended that the caliber .45 pistol
ball cartridge be tested in a trial mechanism to determine whether
it could function satisfactorily without lubrication.
Those were the days of trench warfare on all the battle fronts,
and he had apparently given the matter considerable thought; he
was ready with an answer and a directive. He said “very well,
try out the caliber .45 pistol ammunition immediately to determine
it’s functioning, and if those cartridges function satisfactorily
without lubrication, design and build a machine gun using the
caliber .45 pistol ball cartridge, a gun that can be fired from the
hip; we will call it a “trench broom”. With that he stood up and
gestured with his arms as though he were actually firing a Thompson
Submachine Gun from his hip as it was finally developed. For the
time being, we were to let work on the automatic shoulder rifle\
rest and push the development of a pistol ammunition machine gun
with the utmost speed.
Back at Cleveland we soon made determinations with our Testing Mechanism that the caliber .45 pistol ball cartridge would function satisfactorily with the Blish Bolt action, without lubrication, as we had anticipated; and we made determinations of the wedge angle.
The assignment to design the gun was given to Mr. Payne. In our
rifle design work we had become accustomed to keep the weight of
parts to and absolute safe minimum, so quite naturally we also
designed the machine gun as light as possible. In design we
used a web belt to feed the cartridges into the gun.
In very good time we had the gun ready for testing; but then
our disappointment began. The gun would fire two or three shots
automatically and then jam. We spent considerable time making
adjustments and refinements, but always there was the sound of two
or three encouraging shots and then a jam. Finally we came to the
conclusion that the gun parts were entirely too light and the
movement of the parts entirely too fast to drag into position a
belt of heavy cartridges. We decided to wipe the slate clean and
start allover again, making the parts as heavy as we dared, abandon
the belt feed, using a box magazine feed of 20 cartridges. This
we later supplemented with drum magazines of 50-cartridges and
100-cartridges capacity. Our hunch to design the gun heavier
worked out beautifully and just as the World War I Armistice was
signed, Nov. 11, 1918, we had a Pistol Ball Cartridge Machine Gun
ready for production.
In drafting room and shop parlance we had referred to our first
design of gun as “The Persuader”. The second heavier design we
called “The Annihilator”. But now the time was ripe to give the
child an official name. General Thompson objected to calling the
piece a “machine gun”. All Machine Guns at the time fired rifle
cartridges and he argued that this gun was not in the category with
that class of machine gun. We considered the term “Sub-Machine Gun”
to indicate that it was of a lower category than a rifle cartridge
machine gun, but considered the possibility of the term “sub-
machine” creating confusion with the designation “sub-caliber”. I
contended that the term “sub-caliber” was known only in military
parlance where in target practice small ammunition is fired in
adapters from big guns merely for training purposes, and that the
term ‘sub-caliber’ is not known to the general public. The General
finally conceded to the use of the term “sub-machine”; but now the
question remained whose name should it take. He proposed to call
it “The Ryan Submachine Gun.” When this matter was brought to the
attention of Mr. Ryan for his consent he said very brusquely, “I’m
no military man and what is more I know nothing about guns; General
Thompson is a military man, knows guns, and is well know; we will
call it “The Thompson Submachine Gun.”
With the submachine gun complete, we resumed the design of
the Autorifle. for the first time the General over-ruled my recom-
mendation, which was to wax the cartridge of lubrication. He
instructed us to provide small oil-pads in the magazine of the
rifle to furnish the necessary lubricant to the cartridge. This
disappointed and disheartened me very much; to necessity of
lubricating the cartridge would be a very great handicap for any
rifle we might produce.
As a result of our experience with the submachine gun we
started afresh with the design of a rifle. Here there were greater
pressures to content with and greater speeds of moving parts.
Instead of using a separate wedge we went back to the gun that
Commander Blish first observed and decided to use a bolt with lugs
of the screw-thread type using the appropriate angularity.
Eventually we had an automatic shoulder rifle designed and built
and with appropriate lubrication of cartridges, the rifle
At this juncture, in the fall of 1920, we were instructed to
discontinue our machine shop and office in Cleveland, release all
personnel and a selected few to move to Hartford, Connecticut.
Negotiations had been under way for some time with the Colts Patent Fire-Arms Manufacturing Company to manufacture a limited number of submachine guns for the Auto-Ordnance Corporation and we were to be available at their plant for any engineering assistance they may need.
Not long after we were settled in Hartford, Connecticut,
Oscar V. Payne left the Auto-Ordnance Corporation to take a
position with Crompton & Knowels loom Works at Worchester, Mass.
That left only George Goll and myself of the former Cleveland
organization remaining with the company.
The Colts Patent Firearms manufacturing Company were getting along with their orders from the Auto-Ordnance Corporation in manufacturing submachine guns. Sales, however, did not meet
expectation and we were called upon to design and build temporary
racks for storing guns after they came off the production line
and passed our company’s inspection.
We had gone through World War I, which was popularly hailed
as the War to end all Wars. The future of the gun business did not
look bright, and I entertained a desire to get into Industrial
Work, so in the summer of 1924 I resigned my position with the
Auto-Ordnance Corporation and joined the Trundle Engineering Company of Cleveland, Ohio, as a staff engineer.
After leaving the Auto-Ordnance Corporation, I was in
occasional correspondence with the company regarding the design of an autorifle for the British Cartridge. However, my personal
correspondence with General Thompson was more frequent, and
continued until the time of his death.
Occasionally I would hear bits of news about the Auto-Ordnance Corporation until finally General Thompson sent me a clipping of the Time Magazine, issue of June 26, 1939, where, on page 67, in the Business & finance Section, under the heading of “Munitions” and sub-heading “Chopper”, there appeared a concise article on the history and demise of the Auto-Ordnance Corporation. Mr. Ryan had died in 1928, Manhattan’s guaranty Trust Company became executor, Elder statesman Elihu Root, the lawyer of the Ryan estate, in kindly Pacifist Root’s scheme of things, quietly put Auto-Ordnance on the shelf.
Colonel Marcellus Thompson died in October 1939 and General Thompson died in June 1940.
Russell Maguire acquired the interest that was formerly held
by the Ryan estate and, as I understand, reaped quite a harvest on
the production of Thompson Submachine Guns during World War II.