Chapter IV: Modern Armament

THE ARTILLERY OF A FIELD ARMY; ITS FUNCTIONS.

The artillery assigned to a field army should be of such mobility, power, variety and number as to insure the success of its purpose and to enable this success to be gained with the minimum of casualties. The latter point must receive careful consideration in studies of organization, for without adequate artillery preparation and support the successes of the most gallant infantry can in a series of actions become little more than pyrrhic victories. Many actions of our divisions in France resulted in casualties whose numbers decreased in proportion to the number of guns with which divisions were supported. The proportion of guns to the thousand gross strength of infantry, cavalry, and machine guns adopted by the armies of the first class powers before the opening of the present European War in 1914 was:

British, 6.8; French, 4.6; German, 6.4; American 3.2 (Greble Board).

During the war this proportion was constantly increased until at the close under conditions of position or entrenched warfare it was between 8 and 12 per thousand; this varied of course with the activity in different sectors. In quiet sectors and under conditions of maneuver, or open warfare, which necessitated leaving much artillery behind, it was about 6 per thousand.

A program of types of artillery weapons should be founded on the object and the means—that is, the destruction of the target and the projectile to accomplish this. In the study of an artillery program there are two methods of approaching the subject. First, by starting with a minimum weight of projectile and working up to a reasonable maximum, according to some law and taking the corresponding calibers, a theoretical series of guns and howitzers can be expressed. For instance, if the law be doubling the weight of the projectile the series of types could be:

Projectile of 13 pounds, caliber 3”.
Projectile of 26 pounds, caliber 4”.
Projectile of 52 pounds, caliber 5”.
Projectile of 104 pounds, caliber 6”.
Projectile of 208 pounds, caliber 8”.
Projectile of 416 pounds, caliber 10”.
Projectile of 832 pounds, caliber 12”.
Projectile of 1664 pounds, caliber 14”.

The second and more logical method, and one followed in our service, is to consider the artillery missions and determine the types best suited irrespective of any theoretical series of weights and calibers. However, in the discussion of artillery missions and the proper types for their fulfillment there is a remarkable degree of unanimity of thought on these subjects; and the above table actually contains, with slight variations, the types that are most strongly recommended. While granting the great variety of artillery missions that often shade into each other, it is believed that they can best be considered in three great classes that follow the tactical composition of a field army: those of division, corps and army artillery.

DIVISION ARTILLERY.

=Missions.= The division artillery, first of all, must have the mobility that will permit it to accompany the infantry of a division and the maximum power consistent with that mobility; its object must be primarily the infantry of the opposing division. It is therefore bound to its own infantry with the closest bonds and its tactical use cannot be separated from that of the infantry. The division artillery must fire, accurately, a man killing projectile and be prepared for quick changes of targets; it must have a great range because of depth, both of its own and the enemy division; it must continually harass the enemy, prevent his movement and force him into cover or protected trenches. On the defensive it must break up the opposing infantry formations by preparing a counter-offensive fire and by annihilating fire on points from which the enemy attacks emerge; and, failing in these, be prepared to use the barrage and shrapnel fire at close range. In the offensive the division artillery must play its part in the complex schemes of artillery preparation by cutting wire, destroying machine gun nests, gassing areas, concentrating on infantry positions and taking the principal part in the deep barrage that should precede the infantry attack. Its fire, accompanying the infantry movement, requires its own movement and by its mobility it often becomes for some time the sole artillery protection in the preparation and holding of a position which has been taken.

=Light Gun and Howitzer.= The consensus of opinion of artillery officers is that the division artillery missions are best fulfilled by a light field gun and a light field howitzer having a range of at least 11,000 yards. While differing in mechanical features, the field guns of the different European countries are practically of the same type and, though constant effort is being made to improve details, they can be stated as generally satisfactory to their own governments and not liable to any radical changes. The general type of field gun, while capable of fulfilling most of the division artillery missions, must be supplemented by a proper howitzer. There are many instances where the terrain or the lay of the land offers such protection to the infantry that the field gun cannot bring an effective fire. The howitzer has the great advantage that with the proper set of propelling charges and, therefore, choice of trajectories for the same range, protected positions can be chosen for howitzers that guns could not use, and angles of fall obtained on objectives that the normal ammunition of guns would not give. The low muzzle velocity of howitzers admits of their almost continuous use in harassing fire and allows the use of a projectile double the weight of that of a field gun. Such a howitzer renders excellent service in wire cutting and is a useful projector of gas shells. To insure the mobility required of all divisional artillery the weight of the howitzer and carriage should not exceed that of the field gun, or about 4,500 pounds.

=Light Gun Discussion.= The consensus of opinion of all artillery officers—French, English and American—is that the 75-mm gun, or approximately this caliber, firing a 15-pound projectile or a projectile of approximately this weight, and having a range of not less than 11,000 yards, is a satisfactory weapon at the present time for use with the division artillery. The projectile in question, whether a shrapnel or a high explosive shell, satisfies adequately the criterion of man-killing. At the close of the war the nations were not entirely in accord with respect to their conception of an up-to-date carriage for a light field gun. All the nations whose tendencies have been considered in this report have experienced to a varying degree with field gun carriages, particularly in a desire to design a carriage permitting a greater angle of elevation and greater movement of the gun in the traverse. The Italians have expressed themselves in the modified Deport Carriage; this vehicle is of the split trail type and permits an elevation in excess of 75 degrees, and a traverse on each side of the center of the carriage of about 20 degrees—about 356 mils. Up to the time that the board left France it was not possible to learn the French decision in the matter of a split trail carriage for their light field gun. It is known, however, that several types of this carriage have been designed and tested; it is known, also, that considerable favor has been found with the American 1916, which type has been tested under the auspices of the French Government. In England, however, the board was not able to develop any enthusiasm for the split trail type, although the matter had been seriously considered. In that country the up-to-date field gun carriage appears to be adequately expressed in their new 18-pounder. The vehicle upon which this gun is mounted permits an elevation of 37 degrees and an axle traverse of 4½ degrees on each side. The trail is a box trail and the carriage is simple and steady in its construction and lends itself to rapid production.

=Motorization.= At some time in the future it is probable that all the division artillery will be motorized. The result of such a change in the prime mover would be to remove the present restriction as to weight of gun and carriage. The board senses a demand in the near future for a light field gun having a maximum range of approximately 15,000 yards; such a range may be achieved by increasing the muzzle velocity and, perhaps, the weight of the projectile, although change in the form of projectiles will give some improvement over the present ranges. It is probable that the limiting features in the design of field guns of the future will be the requirement that it should pass safely over temporary pontoon bridges and that the weight and form and size of ammunition must be such that the present rate of fire will not be slowed down. The board is of the opinion that, except as to perfection of details, the limit of carriage design, as expressed by the most modern type of box-trail and split-trail carriages, has been reached; and feels that with the advent of motor transportation the tendency will be toward a gun mounted on a self propelling carriage and expressing the desires of the field artillery with respect to maximum horizontal and vertical arcs of fire.

=Light Gun. Ideal.= A gun of about 3” caliber on a carriage permitting a vertical arc of fire of from 5 degrees depression to 80 degrees elevation and a horizontal arc of fire of 360 degrees; a projectile weighing not over 20 pounds, shrapnel and high explosive shell of satisfactory man-killing characteristics with maximum range of 15,000 yards; fixed ammunition, smokeless, flashless propelling charge; time fuse for shrapnel. With shell having safe fuses with different lengths of delayed action after they land. The high explosive shell should be of one type only. Two propelling charges should be furnished, a normal charge for about 11,000 yards range and a super charge for maximum range. The proportion should be 90% of the former and 10% of the latter. A maximum rate of fire of 20 rounds per minute is deemed sufficient.

=Light Gun. Practical.= For the present, arm brigades with 75-mm materiel. Models 1916, 50%, and 1897 (French), 50%.

=Transport. Ideal.= Mechanical transport is the prime mover of the future. The introduction of mechanical transport will undoubtedly cause far-reaching changes in the types of gun carriages. It is not possible now to state just how far this will go or whether a gun mounted on a self propelled vehicle or one mounted on some type of trailing vehicle will be the final result. Both types may be necessary. It is urgent that study and development be carried along these lines, as we are on the verge of changes fully as radical as the introduction of the long recoil field gun and carriage, and the country first utilizing the new capabilities opened up by mechanical traction and the caterpillar will have a great advantage in the next war. A limit of 4,500 pounds behind the team has heretofore been imposed on the artillery of this class. The corresponding limit in the future will probably be that imposed by pontoon bridges.

=Transport. Practical.= Therefore it is thought that four regiments of 75-mm guns (two regiments of French Model 1897, and two regiments of U. S. Model 1916) should be immediately equipped with motors, the remainder to be horsed; mechanical transport to gradually replace horse only after the tractor demonstrates its superiority in service.

=Light Howitzer Discussion.= The consensus of opinion of American army officers consulted is that a howitzer about 4” in caliber, firing a projectile weighing from 25 to 30 pounds at a maximum range greater than 10,000 yards, is required. This opinion is concurred in by the French, Italians and English, and it appears to be definitely established that the mobility of the light field howitzer should be practically the same as that of the light field gun. The British army was equipped with a 4½” howitzer, firing a projectile weighing 35 pounds and with a maximum range of 7,700 yards; the weight of the howitzer limbered is 4676 pounds—150 pounds more than the weight of the 18-pounder field gun. No evidence was found that the British Government intended making any alterations in the design of this howitzer; naturally they will attempt to increase the range, power and accuracy of the projectile by change in its weight, its capacity and its form. The French artillery was not equipped with the light field howitzer of approximately the same weight as the 75-mm field gun. During the war it was found impracticable to construct a lighter howitzer without interfering with the production of other calibers which were considered more important. In the earlier stages of the war the Italian artillery was not equipped with a light field howitzer; however, before the end of 1917 orders were placed for several hundred howitzers of the 105-mm type. It should be noted that several hundred howitzers of this caliber were being constructed before the armistice and that many have been captured from the Austrians by the Italians; this, so far as the Italians were concerned, makes it certain that a light field howitzer will be furnished by the Italian army. The German and Austrian armies were equipped with a howitzer of the light field type; this weapon had a caliber of 105-mm type.

It fired a projectile weighing 34.54 pounds at a maximum range of 10,500 yards. (Streamline shell.) The weight of the howitzer limbered was 4,500 pounds. In the opinion of the board, the Germans have proceeded on sound principles in their development of the light field howitzer. Their ’98 model was a companion piece to their ’96 field gun and in the years that passed from 1898 to 1916, which included their early war experience, they kept to the idea of the relation of the two pieces even to the extent of including in a field artillery regiment one battalion of light howitzers. Their 1916 models of both light gun and howitzers show the endeavor to keep the pieces in the same class; that is, the weight of the gun and howitzer in action nearly the same, 2,750 pounds and 2,700 pounds; the weight of the gun limbered and the howitzer limbered are the same, 4,500 pounds; the elevation of both the same—minus 10 to plus 40 degrees; the carriages are of the same type; and the extreme ranges of gun and howitzer are respectively 11,700 and 10,500 yards. From the foregoing it is seen that all the important belligerents except the French and the Americans were equipped with a light field howitzer firing a projectile about twice the weight of the light field gun projectile and having otherwise the same general characteristics. There is no evidence to show that the fire of the French and the American artillery was not fully effective as that of any other artillery; however the testimony of the French and American artillery officers is to the effect:

(a) That the lightest howitzer in use, i. e., the 155-mm, was not sufficiently mobile to be a suitable companion piece for the 75-mm gun.

(b) That many times the fire of the 75-mm gun proved ineffective due to its flat trajectory; a howitzer would have been more effective in the attack of certain targets.

(c) That a large volume of fire is necessary.

(d) That while the 155-mm howitzer is more powerful than the light field howitzer its consumption of ammunition for many purposes is wasteful and extravagant and its volume of fire is insufficient.

(e) That the light howitzer is particularly suited for the destruction of wire entanglements; its better accuracy and more powerful projectile make it more suitable than the field gun for that purpose.

(f) That the 75-mm field gun projectile is not so satisfactory a gas shell as the howitzer projectile which has greater weight.

=Light Howitzer. Idea.= A weapon of about 105-mm caliber on a carriage permitting a vertical arc of fire from minus 5 degrees to plus 65 degrees, and a horizontal arc of fire of 360 degrees. Efforts should be made to develop a carriage which can be used interchangeably for the division light gun referred to above and this howitzer. The projectile should weigh about 30 to 35 pounds and should include both shell and shrapnel. A maximum range of 12,000 yards will be satisfactory. Semi-fixed ammunition with varying charges should be used, otherwise the ammunition should be similar to that provided for the 75-mm guns.

=Light Howitzer. Practical.= For the present, the division should be armed with the 155 howitzer, Schnieder, but active development and test should be made on a type as stated under “Ideal” above, and with the ammunition and other accessories to it. Upon the development of the carriage as nearly approximating the ideal as may be practically possible, efforts should be made to secure quantity production in order that it may be incorporated in the division as recommended. In addition, a split trail carriage for this howitzer should be developed.

=Transport.= The light howitzer should have the same means of transport as the light field gun and the same remarks heretofore made as to the probable future development of the field gun also apply to the howitzer carriage.

CORPS ARTILLERY.

=Missions.= It will be noted above that the division artillery missions did not include their own protection against the enemy artillery. This counter-battery work is the principal mission of the corps artillery. The corps artillery has also the mission of extensive harassing and interdicting fire along the corps front and to a greater depth than the capabilities of the division artillery; also of destructive fire on strong points as well as on railroad facilities and points of supply. For the accomplishment of these corps artillery missions there are two types of artillery necessary, a gun and a howitzer, each having 16,000 yards range and each weighing with the carriage about 11,000 pounds. There is another class of artillery called anti-aircraft artillery to be considered. This is used first in providing anti-aircraft defense for army zones, for certain areas in rear of armies or along a certain line of anti-aircraft defense.

=Medium Gun Discussion.= The consensus of opinion of artillery officers—Italian, English and American—is that a medium gun of about 6” caliber is necessary. The medium type gun furnished to the American army was the 4.7 (Model 1906). This gun has a maximum elevation of 15 degrees with a corresponding maximum range of 8,750 yards. The British army was equipped with the 5” gun—the carriage permits a maximum elevation of 21 degrees and 30 minutes, giving a maximum range of 12,500 yards. The French army was equipped with, to a certain extent, the 105-mm and the 140-mm gun. The 105-mm gun a maximum elevation of 37 degrees, with a maximum range of 13,900 yards. The 140-mm gun has a maximum elevation of 30 degrees and, with a high velocity, has a maximum range of 19,500 yards. The French 105-mm gun is a modern weapon (1913). The German artillery was equipped with a 105-mm gun (M-1917) with a maximum elevation of 45 degrees, and a maximum range of 16,000 yards. The German army was also equipped with the 130-mm gun, having a maximum range of 16,500 yards. The Austrian army was similarity equipped. The Italians were equipped with a 105-mm gun essentially of the same characteristics as the French 105-mm M-1913.

=Medium Gun. Ideal.= A caliber of between 4.7 and 5” on a carriage permitting a vertical arc of fire of from minus 5 degrees to plus 80 degrees; a horizontal arc of fire of 360 degrees. Shrapnel and shell weighing not over 60 pounds, maximum range 18,000 yards; with semi-fixed or separate loading ammunition permissible.

=Medium Gun Practical.= Corps artillery should be armed with the present type 4.7” gun, Model 1906, except that at least one regiment should be armed with the British type 5”-guns purchased abroad.

=Transport.= All corps guns should be developed for long, rapid hauls. Similar ammunition vehicles should be developed. The wheels for the gun carriage should be rubber-tired.

=Medium Howitzer.= In the opinion of the French, Italians, British and the Americans, the 155-mm howitzer (Schnieder) was conspicuously successful in the present war. It should, therefore, be retained as a type. The howitzer and carriage as it stands at present, is a highly satisfactory and efficient piece of armament. For the future it is believed that effort should be made to increase the range by improvements in the form of projectile, and it is believed that the form of howitzer and carriage should be studied with a view of obtaining, through modifications, a maximum range of approximately 16,000 yards.

Many batteries of 155-mm howitzers (Schnieder) were motorized in the American Army in France, and the consensus of opinion is definitely toward the retention of this form of prime mover. It is interesting to note that all the important belligerents have settled upon a howitzer of approximately 6” in caliber, and otherwise essentially of the same ballistic characteristics as the type in question. The projectile of this caliber is the smallest projectile which can be called upon to give adequate mining effect against material targets of semi-permanent nature. The place of this howitzer is, therefore, determined by considerations of its destructive ability. It is a splendid destruction and neutralizing weapon.

=Medium Howitzer. Ideal.= A caliber of about 155-mm on a carriage permitting a vertical arc of fire of from minus 5 degrees to plus 65 degrees; and a horizontal arc of fire of 360 degrees. The projectile should not weigh over 100 pounds and should be interchangeable with projectiles for other guns of this caliber referred to later on. High explosive shell, only, should be supplied.

=Medium Howitzer. Practical.= The corps should be armed with the 155-mm (Schnieder) howitzer referred to above. The type of fuses for shell should be super quick and long delay.

ARMY ARTILLERY.

=Missions.= In addition to the division and corps artillery fulfilling the missions outlined above there must be additional artillery available. There are missions of interdiction, neutralization and destruction which fall beyond the activities or capabilities of the normal corps or medium field types; there must exist a surplus of division or corps types, properly transported, for strategic reinforcements of divisions and corps during such times as the normal allotment to such units is insufficient; there must be artillery of special purpose—mountain artillery, trench and super guns and howitzers. Of the above additional artillery, a type of heavy field gun and a type of heavy field howitzer are considered normally necessary in the armament of a field army; the gun should have a range of approximately 25,000 yards, and the howitzer a range of about 18,000 yards. These weapons are more powerful than the medium field types, add range to the interdiction and harassing and to the neutralization and destruction possible with the corps type. Considering the paragraphs pertaining to divisional artillery and the introduction to corps artillery _it will be seen that the normal artillery of a field army can be accomplished by the assignments of two caliber, i. e., two light weapons, two medium weapons and two heavy weapons—a gun and a howitzer in each class—and a satisfactory anti-aircraft gun_.

=Heavy Field Gun.= The consensus of opinion of all artillery officers—British, Italian and American—is that the heavy field gun should be of approximately 6” caliber and that guns of greater caliber than this are necessary in limited number for field operations. The French were constructing 194-mm guns during the latter stages of the war. It is believed that in developing this type of gun the French were actuated almost entirely by the necessity for increased range, since the German 150-mm gun, Model 1916, outranged the G. P. F. by approximately 5,500 yards. The French have recently made considerable progress in securing the necessary increase in range with the G. P. F. All of the principal nations engaged in the war used a heavy field gun of approximately 6” caliber. This type has given such general satisfaction that its continuance is assured. The principal mission of the heavy field gun is harassing and interdiction fire, and for these uses the 6” projectile is sufficiently heavy. The maximum practicable traverse and elevation should be provided by the carriage of the heavy field gun. The G. P. F. carriage has given general satisfaction, but its wide tread and the excessive time required to occupy a position are very objectionable features. It is the consensus of all artillery officers—French, British and American—that the heavy field gun should be of approximately 6” caliber and with a range in excess of 25,000 yards, with not less than 60 degree traverse, weighing not more than 12 tons, limbered, capable of occupying and leaving a position quickly, and with a width of tread which does not prevent two-way traffic on ordinary roads. The Italians differ from this opinion only in that they are satisfied with a maximum range of 18,000 yards.

=Heavy Field Gun. Ideal.= A caliber of about 155-mm on a carriage permitting a vertical arc of fire from 0 degrees to plus 65 degrees; with a horizontal arc of fire of 360 degrees. The maximum range should be about 25,000 yards.

=Heavy Field Gun. Practical.= Arm with the present type 155-mm G. P. F. and carry on experiments for type of carriage as outlined for division field gun. The fuses should be super-quick and short delay.

=Transport.= All artillery of this type should be motorized and tested and experiments for ammunition vehicles to correspond with the types of carriages developed, and should be carried on simultaneously.

=Heavy Field Howitzer.= No type of heavy field howitzer developed during the war has given general satisfaction. The consensus of all army artillery officers—French, English and American—is that two calibers of howitzers are necessary—one a companion piece for the 6” gun and one of the maximum possible power consistent with the necessary mobility. The lighter of these two howitzers should have the same mobility as the 6” gun, with a caliber of about 8” and a maximum range of not less than 16,000 yards. The heavy field howitzer should be of about 9.5” caliber with a range in excess of 16,000 yards; the carriage should provide for wide traverse and must have sufficient mobility to accompany the army in the field. It will probably be necessary to transport this howitzer in more than one load, and the maximum weight of any load should not exceed 12 tons. The average time necessary for occupying a position should not exceed six hours under actual field conditions.

=Heavy Field Howitzer. Ideal.= A caliber of about 8” on a carriage permitting a vertical arc of fire of from 0 to plus 65 degrees; and a horizontal arc of fire of 360 degrees. The maximum range should be 18,000 yards.

=Heavy Field Howitzer. Practical.= Use at present 8” material of British design which is on hand.

=Railway Artillery.= The war has demonstrated the necessity for long range and powerful guns for distant interdiction and harassing work and for super-heavy howitzers for the destruction of semi-permanent fortifications. Artillery of these types can best be mounted on railway carriages and this type of mount offers no serious disadvantages since these guns will not be used except with large forces which require extensive railroad systems for their supply. This does not apply to guns of the type used to bombard Paris; such guns have no military value and their construction is not justifiable.

ANTI-AIRCRAFT GUNS.

=Light Gun. Ideal.= Caliber about 3” with initial velocity of at least 2,600 f. s.; semi-automatic breechblock, mounted on carriage, permitting 80 degrees elevation and 360 degrees traverse; projectiles weighing not less than 15 pounds, of one type high explosive shell with maximum ballistic qualities and as large explosive charge as possible; fixed ammunition; smokeless, flashless powder, mechanical fuse. In this type every effort must be made to increase the rate of fire and decrease time of flight; this latter is limited only by considerations of a reasonable accuracy life for the gun.

=Light Gun. Practical.= Arm units with present 3” anti-aircraft equipment. Continue experiments leading to the development of the ideal.

=Transport. Ideal.= Caterpillar mount or caterpillar trailer mount drawn by caterpillar tractor, each unit to permit a sustained speed of 12 miles per hour.