Page:EB1922 - Volume 31.djvu/1247

of the powder charge withdrawn. The Germans used their " 96 n.A." field gun, with slight modifications, as a horse artillery gun.

Mountain Guns. Even before the war, the principal gun-makers produced 15-pdr. mountain guns light enough for pack transport, namely, with the heaviest top load not exceeding 250 Ib. net. How- ever, the guns used in the war were mostly I i-pdr., though the Greek Schneider- Danglis gun was a l43-pdr. The British pre-war mountain gun was a io-pdr.. and a I2j-pdr. was issued" in 1914. It is now con- sidered that a mountain gun should fire a 15-lb. shell, and new equip- ments are under trial in several countries. The new U.S.A. equip- ment is styled a mountain howitzer, and is described below.

FIG. 20. British 3'7-in. mountain howitzer.

The British I2j-pdr. mountain gun is in two pieces, joined by a nut; its calibre is 2-75 in. It fires a bare charge, not fixed ammunition, and its range is 5,800 yd. at 15 elevation. The carriage has a cranked axletree, which can be revolved to bring the cranked portion uppermost when firing, to allow room for the gun to recoil. The buffer and running-up springs of ordinary pattern are contained in the trough-shaped cradle; the top of the cradle is closed by the " slipper " (corresponding to the Krupp " sleigh ") which slides on the cradle-guides during recoil and run-up. The gun when put together is secured to projections on top of the slipper. This gun will be replaced by a 15-pdr. on the same lines as the new U.S.A. mountain equipment, fitted for draught as well as pack carriage.

Mountain Howitzers. These are subject to the same limitations of pack loads as mountain guns, but have to be heavier as a whole in order to fire a shell weighing 20 to 25 Ib. The extra weight is ob- tained by increasing the number of loads. A good specimen of pre- war equipments is the British 3'7-in. mountain howitzer, which is noteworthy as being the first split-trail equipment introduced into the British service (see fig. 20). It fires a 2O-lb. shell and ranges 5,800 yd. The howitzer is in two parts. It has controlled recoil gear similar to that of the 4'5-in. field howitzer described above. The equipment forms 8 mule-loads.

FIG. 21. U.S. pack howitzer, 1920.

A more modern specimen is the 1919 French Schneider lO5-mm. (4-2-in.) mountain howitzer. This is a 26'4-pdr. ranging 9,000 yd. at 40 decrees. Unlike the British mountain guns, it is not divided half- way down the bore; the division is in rear of the powder-chamber. The gun, 13 cats, long, consists of the barrel and the breech-piece, the latter being prolonged into a jacket which fits loosely round the gun and serves the purpose of increasing the recoiling weight so as to red ice the recoil. This construction has been used in the Greek Schneider mountain gun and has stood the test of war. The cradle is of the same length as the gun, and contains the ordinary Schneider hydro-pneumatic gear, charged with compressed nitrogen instead of compressed air. The gun recoils on a slipper as in the British mountain gun. The cradle trunnions are set far to the rear, giving a forward preponderance, but no balance spring is used ; the height of the line of fire is 31 in. with 36-in. wheels, and this gives room for

the full recoil of 335 in. at 40 elevation without the breech striking the ground. The piece traverses on the axle as in most French equip- ments, and the total traverse is 160 mils or 9-6 degrees. Six of the seven pack-loads are above the 25O-lb. limit observed in the British and American services.

The U.S.A. pack howitzer, Model 1920, fig. 21, replacestheU.S.A. mountain gun. It fires the same 15-lb. shell as the field gun, M.V. 900 f.s., ranging 6,600 yd. It has the St. diamond recoil gear re- ferred to above. The howitzer has rear cradle trunnions and balance spring, the latter being a torsion sprinp coiled round the axle. The carriage is on 2Q-in. wheels and gives 45 elevation and 2-J- traverse, but a split-trail carriage is under trial. The howitzer and carriage form 4 loads of 235 Ib. net. This equipment is to serve as a gun of accompaniment as well as a mountain gun, in addition to the " infantry howitzer " described below.

Guns of Accompaniment. These are required to accompany the infantry, to deal with machine-guns and strong points that have escaped the barrage, and to protect the infantry against tanks that may attack them. The necessity for some form of gun of accom- paniment was generally recognized during the last two years of the war; in the absence of specially designed weapons the infantry used anything they could get. Thus the German infantry used their field gun on 3-ft. wheels, captured Russian horse-artillery guns, field guns on semi-mountain carriages borrowed from the Austrians, German and Russian mountain guns, light trench-mortars adapted to direct fire, and German 57-mm. 6-pclr. taken from fortresses. The British used the few 3'7-in. mountain howitzers available, the 6-in. Newton trench-mortar on an improvised carriage, and captured German light trench-mortars. Further, the British detailed sections of l8-pdr. and the Germans batteries and sections of 77-mm. field guns to ac- company the infantry.

FIG. 22. U.S. Christie reconnaissance tractor, 1920.

The Germans brought put a gun of accompaniment in 1918, but only a few were ready in time to take part in the fighting. This was the " infanteriegeschutz 18," a reduced copy of the "96 n.A." field gun, and capable of firing the same 15-pdr. ammunition with part of the charge withdrawn. The length was 23 cals. against 27! for the field gun; the M.V. was 1,170 f.s. and extreme range 5,500 yd. The weight in action was 13-7 cwt. This weapon seems to be not powerful enough for a regular field gun, and not mobile enough for an infantry gun; it was a compromise to which the Germans resorted in preference to introducing a special calibre and complicating their ammunition supply. The Germans have chosen to retain this gun in the small peace establishment permitted by the Peace Treaty.

The only nation which has brought out a special gun of accom- paniment since the war is the United States. This piece is styled the Infantry Howitzer. It is of 2-24-in. cal., and has two projectiles, a 6-lb. H.E. shell for direct fire, M.V. 700 f.s., and a lo-lb. shell for curved fire. This piece is to supersede the 37-mm. infantry gun used by the French and Americans during the war, and to supplement the 15-pdr. pack howitzer. It is mounted on a wheeled carriage with cranked axle, which can be turned inwards when the piece is used for curved fire. The equipment is divisible into man-loads, the heaviest the howitzer itself weighing 80 Ib. ; this is carried by two men. The total weight is 300 Ib. The howitzer is to be taken forward as far as possible by a Christie motor-cart (fig. 22) , a small cross-country vehicle weighing only 600 Ib. ; thence the howitzer is run forward by hand, and the cart follows with ammunition.

Medium Guns. Medium guns are long-range guns sufficiently mobile to march with an infantry division and to come into action in support of the infantry without any preparation such as building platforms. In the British service the medium gun is the 66-pdr., weighing about 5 tons and drawn by a team of heavy horses. The first model of this was a very useful gun in its time, and was re- markably accurate; it fired both shrapnel and H.E. shell, and ranged 10,000 yd. A new pattern with under-cradle was issued in 1918, which ranged 15,000 v,d. with a pointed shell with 8-calibre head. The Germans had the 13-cm. (5-i-in.) gun of 1910, which threw an 88-lb. shell 15,700 yd., as well as various patterns of 10-5 cm. Their pre-