Chapter XVI: Small Arms

Notes on the Automatic Pistol, Cal. 45, Model 1911.

The pistol is known as the Automatic Pistol, Cal. 45, Model 1911. By caliber is meant the caliber of the bore. All pistols used in the service are marked on the left side of the receiver, “United States Property,” and on the right side with the serial number, which must be memorized by the person to whom the pistol is issued.

It is important that every man have a thorough knowledge of the nomenclature, care and repair, method of assembling and dismounting the pistol as well as its use and operation.

=The principal parts= of the pistol are the _receiver, the barrel and the slide_.

=To Dismount and Assemble the Pistol=:—Press the magazine catch and remove the magazine. Press the plug inward, turn the barrel bushing to the right and by easing off on the spring let the plug and spring protrude gradually. Draw the slide to the rear until the small recess is opposite the thumb piece of the slide stop. Press gently against the end of the pin of the slide stop on the opposite side and remove the slide stop. This releases the link and allows the barrel and the slide with all its parts to be slid forward off the guide rails of the receiver.

=To Disassemble the Slide=:—Remove the plug by turning it to the left and withdraw the recoil spring with its guide from the rear; or remove the recoil spring guide and withdraw the coil spring with its plug from the front. Turn the barrel bushing to the left and withdraw it forward from the slide. The barrel may now be withdrawn from the slide. To remove the firing pin, press the rear end of the pin forward until it clears the firing pin stop. Then withdraw the stop downward from its seat, whereupon the firing pin, the firing pin spring, and the extractor are removed by withdrawing them to the rear.

For ordinary cleaning, no further dismounting will be found necessary and no disassembling of the receiver should be permitted except by permission of an officer. When the interior of the pistol has been exposed to water, or when it is desired to make repairs, the receiver may be completely dismounted as follows:

Cock the hammer, move the safety lock to a position half way between its upper and lower position. Press the end of the safety lock pin on the opposite side and withdraw the safety lock. Now lower the hammer by pressing the trigger. Push out the hammer pin and take out the hammer and strut. Next push out the housing pin. This may require a little extra pressure. It is the only pin pushed out by pressure from the left side of the receiver. The main-spring housing may then be withdrawn downward and the grip safety withdrawn to the rear. This exposes the sear spring, which is easily removed. By pushing out the sear pin, the sear and the disconnector are released.

The main-spring housing is disassembled by compressing the main spring, pushing out the small main-spring cap pin, whereupon the main-spring cap, the main spring and the housing pin retainer will come out. The main spring may be easily compressed by using the pin of the slide stop.

To remove the magazine catch, press the button inward. By means of a small screw driver or the short leaf of the sear spring, give the screw head of the magazine catch lock a quarter turn to the left and remove the magazine catch. The trigger can then be withdrawn to the rear.

The hammer strut, a small nail or the long arm of the screw driver may be used to push out all pins except the main spring cap pin and the ejector pin. To remove these a tack or pin may be found necessary.

To assemble the pistol proceed in the reverse order, except that the main spring housing should be left to project about one-eighth inch. Do not push the main-spring housing home and insert the housing pin until after the safety lock is replaced and the hammer lowered.

=The Operation of the Pistol.=—The act of drawing back the slide in loading cocks the hammer, compresses the recoil spring, permitting the magazine follower to raise the upper cartridge into the path of the slide. Upon releasing the slide, the recoil spring forces the slide forward, carrying the first cartridge into the chamber of the barrel. As the slide approaches its forward position, it encounters the rear end of the barrel, forcing the latter forward. Since the front of the barrel pivots in the barrel bushing and the rear end is free to swing upward on the link, the rear end of the barrel is raised, causing the locking ribs on the outside of the barrel and the inside of the slide to engage, thus positively locking the barrel and the slide together. The joint forward movement of the barrel and the slide (about three-eights of an inch) is stopped when the barrel lug encounters the pin of the slide stop.

The pistol is then ready for firing. When the hammer is cocked, the hammer strut moves downward, compressing the main spring. The sear, under the action of the long leaf of the sear spring, engages its nose in the notch of the hammer. Upon pulling the trigger and pressing on the grip safety, the sear is moved, thus releasing the hammer. The latter then strikes the firing pin which transmits the blow to the primer of the cartridge. The explosion of the cartridge generates the necessary gas pressure to force the bullet through the barrel, the initial muzzle velocity being about 800 ft. per second. The pressure exerted to the rear against the face of the slide carries the latter and the barrel to the rear together. But due to the link attachment, the barrel is almost immediately swung down and unlocked from the slide, leaving the slide to continue its movement to the rear, thus opening the breech, cocking the hammer, extracting and ejecting the empty cartridge and compressing the recoil spring. When the slide reaches its rearmost position the magazine follower raises another cartridge into the path of the slide. This cartridge is then forced into the barrel by the forward movement of the slide as before described.

Although it might be supposed that the downward swinging of the barrel would affect the accuracy of the fire, this is not the case. The bullet has gained its maximum velocity and passed out of the muzzle before the unlocking movement between the barrel and slide commences.

When the magazine has been emptied the magazine follower is free to press against the projection on the slide stop, thus forcing the slide stop into the front recess of the slide, thereby locking the slide in the open position and reminding the person firing that the empty magazine must be replaced before firing can be continued.

Interesting Facts about the Pistol.

(a) Weight 2½ pounds. Trigger pull, about 7 pounds.

(b) Rifling, 6 grooves with left-hand twist. The drift due to the rifling is therefore to the left, but this is more than neutralized by the pull of the trigger when the pistol is fired from the right hand.

(c) For ranges up to 75 yards the trajectory is very flat and the drift slight, giving the pistol great accuracy.

1. Receiver.
2. Barrel.
3. Slide.
4. Plunger Tube.
5. Slide Stop Plunger.
6. Plunger Spring.
7. Safety-lock Plunger.
8. Slide Stop.
9. Rear Sight.
10. Front Sight.
11. Link.
12. Link Pin.
13. Barrel Bushing.
14. Recoil Spring.
15. Recoil Spring Guide.
16. Plug.
17. Extractor.
18. Ejector.
19. Ejector Pin.
20. Firing Pin.
21. Firing Pin Spring.
22. Firing Pin Stop.
23. Hammer.
24. Hammer Pin.
25. Hammer Strut.
26. Hammer Strut Pin.
27. Mainspring.
28. Mainspring Cap.
29. Mainspring Cap Pin.
30. Sear.
31. Sear Spring.
32. Sear Pin.
33. Disconnector.
34. Trigger.
35. Grip Safety.
36. Safety Lock.
37. Mainspring Housing.
38. Housing Pin.
39. Housing Pin Retainer.
40. Lanyard Loop.
41. Lanyard Loop Pin.
42. Magazine Tube. }
43. Magazine Base. }
44. Magazine Pins (2). }
45. Magazine Loop. } Magazine
46. Magazine Spring. }
47. Magazine Follower. }
48. Magazine Catch.
49. Magazine Catch Spring.
50. Magazine Catch Lock.
51. Stocks, Right and Left.
52. Stock Screws (4).
53. Screws Bushings (4).
]

(d) Beyond 250 yards the trajectory is very curved and the drift becomes considerable. Firing is therefore very inaccurate.

(e) To hit a target at ranges over 75 yards it will be necessary to lay on a displaced point above and to the right of target for ranges approximately as follows:

_Vertical_ _Lateral_
_Range, Yards._ _Displacement._ _Displacement, right._
100 ½ yard ½ yard
150 1½ yards ¼ yard
200 3 yards 1 yard
250 5 yards 2 yards

(f) The striking energy of the bullet is sufficiently great to surely disable a man by causing a dangerous wound at all ranges up to 500 yards.

(g) The pistol has been fired by experts at 25 yards, aimed fire, at the rate of 21 shots (3 magazines) in 30 seconds. Such rapidity is, however, not necessary or desirable in service firing. Accuracy is always the first consideration.

Precautions.

1. Whenever the pistol is taken out of or returned to the arm rack, also both before and after drill or other exercises with the pistol, remove the magazine and see that it is empty. Then draw back the slide which will eject any cartridge in the chamber. Finally look through the bore to see that the pistol is unloaded and the bore not obstructed by a plug or wad. Replace all parts, come to raise pistol and lower hammer.

2. Never place the trigger finger within the trigger guard until it is intended to fire and the pistol pointed toward the target.

3. Do not carry the pistol in the holster with the hammer cocked and the safety lock on, except in an emergency.

4. Always press the trigger with the forefinger.

5. After each shot relieve the pressure on the trigger so that the sear may re-engage.

6. When inserting the magazine be sure that it engages the magazine catch. Never insert the magazine by striking it smartly; always apply a continuous push.

7. The pistol must be kept clean, free from rust and properly oiled.

8. Never disassemble the receiver except by permission of a officer.

9. In disassembling the receiver be sure that (a) the disconnector and sear are properly assembled; (b) that the hammer is not snapped when the pistol is partially assembled; (c) that the stocks are not removed; (d) that no hammer is used in either assembling or disassembling.

Care and Cleaning of the Automatic Pistol.

In =cleaning= the barrel of the automatic pistol after firing proceed as follows: Swab out the bore with soda solution to remove powder fouling. Remove and dry with a couple of patches. Examine to see that no patches of metal fouling are in evidence, then swab out with the swabbing solution—a dilute metal-fouling solution. The amount of swabbing required with the swabbing solution can be determined only by experience assisted by the color of the flannel patches. Normally a couple of minutes’ work is sufficient. Dry thoroughly and oil with sperm oil.

The proper method of =oiling= a barrel is as follows: Wipe the cleaning rod dry; select a clean patch and thoroughly saturate it with sperm or light slushing oil, being sure that the oil has penetrated the patch; scrub the bore with the patch, finally drawing the patch smoothly from the muzzle to the breech, allowing the cleaning rod to turn with the rifling. The bore will be found now to be smooth and bright so that any subsequent rust or sweating can be easily detected by inspection.

The principles as outlined above apply equally well for the care of the barrel of the sub-calibre cartridge.

MACHINE GUNS AND AUTOMATIC RIFLES AS EMPLOYED BY THE ARTILLERY.

The field artillery employs machine guns and automatic rifles only defensively, either against hostile aircraft, or against enemy infantry in case of a break-through. For this reason the tactical use of these weapons by the artillery is considerably different from that by the infantry, and the dispositions that must be made are adapted to particular needs.

* * * * *

The field artillery must defend itself:

(a) On the march.
(b) In position.
(c) At the echelon (horse-lines).

Defense on the March.

1. Machine Gun.

Machine guns may be used on the march in case of surprise attack or against low-flying aeroplanes. Fire on roads and convoys from low-flying aeroplanes has been developed to such an extent that it is imperative at all times for a column to be prepared to defend itself against such attacks.

1. When a battery is in the advanced zone, one machine gun is mounted on a special mount on the second caisson of the fifth section. This gun is kept ready for fire at all times, the loaded belt if it is a Browning, being kept in the loaded position. About 500 rounds Cal. 30 ammunition are carried on the caisson. The machine gunner in charge of the gun marches with the 5th section.

A mechanic can very easily modify the special mount for the Browning, for use against aircraft, so that it also will be adaptable for use on the caisson.

One gun is attached to the fifth section, so that on subdivision of the battery for action, the other gun will be with the Combat Train or echelon, being carried in the battery wagon or the park wagon.

The second gun may be carried stored in the battery wagon or on escort wagon. In position warfare the firing battery goes into position usually at night. The escort wagon then goes up with tools, officers’ rolls, etc. and the machine gun with its special mount, the regular tripod, and about 2000 rounds of ammunition. If not carried as stated, provision must be made for carrying the gun with the firing battery.

2. Automatic Rifles.

The automatic rifles are assigned one to each section.

All eight automatic rifles should be in readiness for instant use when on the march. They should be evenly distributed throughout the battery, and handled by men who have had special training. At least two magazines per gun (40 rounds) should be instantly available. While it is difficult to bring down a plane with a machine gun or rifle, a well directed fire will limit the action of hostile planes.

It should be borne in mind that often when in the advanced zone friendly aeroplanes are detailed to guard a battery on the march. Great care must be taken to make no mistakes in identifying aeroplanes. Never shoot at a ship unless the distinctive markings on the wings are clearly distinguished and identified. Upon subdivision for action, the automatic rifles go with the section to which assigned. This, of course, may be varied according to the situation.

(B.) Defense of the Position.

The machine gun emplacement should be carefully selected and constructed. The first consideration is a good field of fire; the second is good concealment.

Usually it is placed on a flank of the battery. Situated on the flank of the battery, a greater field of fire is obtained for the gun. Moreover when firing against hostile airplanes, the position of the battery will not necessarily be disclosed. In case the battery is shelled, the position of the machine gun on the flank renders it less liable to be hit.

The emplacement for a machine gun at a battery position differs from those generally built by the infantry in that it is designed primarily for anti-aircraft shooting.

There can be no overhead cover, all protection being provided by well constructed concealment. Camouflage must be arranged for and so placed that it can be instantly thrown aside for firing.

The plans for close defense of the battery should include the assignment of positions and sectors of fire for the automatic rifles.

The methods of fire and the technical points involved, in firing against hostile airplanes, will be considered elsewhere. A sentinel equipped with a pair of field glasses must be on duty in the emplacement at all times. The members of the machine gun squad are detailed for this duty by roster.

Types of Anti-Aircraft Mounts.

The Ordnance Department furnishes no anti-aircraft mount, but improvised mounts can be easily made.

BROWNING MACHINE GUN—MODEL 1917.

The Browning Machine Gun, Model 1917, is water-cooled and is chambered for caliber .30 U. S. Standard Rifle Ammunition. The gun is classed as a heavy water-cooled gun, recoil operative and belt fed.

The water jacket holds about 7 pints of water and is perfectly smooth on its interior. The steam escape tube is in the top of the water jacket, and is made up of two tubes. They slide one upon the other, the outer one being a little shorter than the inner one. This allows the outer tube to slide toward either end and uncover the highest steam escape hole. The force of recoil is utilized to perform the various mechanical operations of feeding in the cartridges, loading, cocking, firing the gun and ejecting the empty shells through the bottom.

The several cams of the gun make each moving part of the gun have a positive motion.

The feed belt is made of woven fabric and has no metal parts to cause feed jams and to add extra weight to the piece. Also the metallic disintegrating links are used with the aeroplane gun. The fibre belt usually contains from 250 to 500 rounds. The metallic belts can be made to contain any number of rounds desired.

The gun has very few screws and springs. It is composed of about forty parts which may be taken down in the field. There are a few parts which can be assembled incorrectly and it cannot be determined that they are so assembled until the gun is ready to be put into action. At this point the gunner will find that the gun will not operate, therefore great care should and must be used in the study of a quick and positive assembling.

The weight of this gun is about 30 pounds without water. This weight makes it necessary to use the gun on a tripod or other suitable mount.

General Data.

Weight of the gun—no water 30 lbs.
Weight of the gun filled 36.75 lbs.
Weight of the belt, 250 rounds 15.25 lbs.
Length of the barrel 24 in.
Weight of the belt, empty 7.5 oz.
Sight graduated to 2800 meters.
Rate of fire (shots per minute) 400-525.
Aimed shots per minute 120.
Calibre of bore .30 in.
Weight of bullet 150 grs.
Weight of cartridge 394 grs.
Chamber pressure lbs. per sq. in. 47,000-50,000.
Muzzle velocity (ft. per sec., theoretical) 2700.

THE BROWNING AUTOMATIC RIFLE.

General Description.

The Browning Automatic Rifle, Model of 1918, is chambered for the United States standard ammunition. This rifle is classified as a light automatic rifle commonly referred to as the “Light Browning.” It has been fired 148 shots per minute, semi-automatic, while marching, and 110 shots per minute, semi-automatic, from the shoulder while in prone position. The rates of fire, which give the best results are from 80 to 100 rounds per minute, semi-automatic marching fire and 50 to 60 shots per minute, semi-automatic aimed fire.

Operation.

Expanding powder gases furnish the energy for the operation of the gun. After the gun is fired and the bullet has passed the gas port in the barrel, the live powder gases expand through the gas port into the gas cylinder and impinge against the head of the piston. This sudden blow forces the piston to the rear, compressing the recoil spring and storing up energy for the return movement. The various lugs and cams actuate the feeding, firing, extraction and ejection, and also control the operation of the gun. The feeding is accomplished through a magazine holding 20 or 40 rounds in double rows. It is held between the sides of the receiver, in front of the trigger guard. This magazine is composed of a rectangular tube and a round wire spring wound to fit the tube. Also there is a bottom plate which slide in the bottom and forms the rest for the spring. On top of the spring is a follower, which forces the cartridge up against the lips of the magazine tube and which holds it in place until stripped out by the lug on the bottom of the bolt. The automatic action of this gun is not disturbed by holding it in any position whatever. The magazine can be inserted while the mechanism of the gun is in either the cocked or forward position.

All parts of the gun are designed so as to impose a minimum of shock and strain upon them. They are also made strong enough to hold up under the maximum amount of work that they can be made to perform. There are few parts that can be assembled incorrectly but the gun will not function unless these parts are assembled correctly. The dismounting and assembling of the rifle can be accomplished without the aid of a single tool unless the barrel and gas cylinder are removed which necessitates the use of a special spanner wrench provided in the kit.

General Data.

Weight of gun 15 lbs. 8 oz.
Weight of Magazine, empty (20 rounds) 7 oz.
Weight of Magazine, filled (20 rounds) 1 lb. 7 oz.
Length of barrel 24 inches.
Sights graduated up to 1,600 yards.
Calibre bore 0.30 inch.
Gas port form muzzle 6 inches.
Rate of fire 500 shots p’m.
Aimed shots per minute, semi-automatic 60 shots p’m.
Weight of bullet 150 grains.
Weight of Powder 47 grains.
Weight of Cartridge (total) 395.5 grains.
Chamber pressure, pounds per square
inch 47,000 to 50,000.
Muzzle velocity 2,682 ft. p’s.
Habitual type of fire semi-automatic.

Cooling System.

It has no special cooling system or device, the barrel merely being exposed to the air and the hand of the firer being protected on the under side of the barrel by a large wooden forearm. Since the barrel soon becomes very hot, care must be taken to avoid touching it during firing or for five or ten minutes thereafter.