Johnsons Early Interest in Guns

Johnson, Jr., was born in August 19U9 in Boston, Mass., and attended Noble Grecnough Preparatory School in Boston and Dedham. At an early age he began to do big-game hunting in the Maine woods, and when he was 14 years old, Hunting and Fishing magazine printed an article by Johnson on sporting arms with some reference to military weapons. This latter is one instance of his early aptitude for the study of weapons. After finishing his preparatory schooling, Johnson entered Harvard...

Chronology of Development

During the early part of 1944, the Johnson organization prepared the third model, which was somewhat more complicated due to the imposition of certain service requirements such as bottom ejection, right- and left-hand feed, provision for charging devices, removable barrel, etc. There was no objection to ultimate provision for these essentials but it was felt that more progress might have been made by carrying out the building of the second model, which probably would have functioned more...

Firing on and June

Acting upon instructions received from the Ordnance Department, the T24 gun was shipped to Aberdeen Proving Ground on 13 June 1945, where it underwent tests at the ballistic research laboratory on 14 and 15 June 1945. These tests consisted of taking time spark photographs, recording velocity of recoil, trunnion reaction, etc. Also acting upon instructions from the same source in a letter dated 2 June 1945, the tube had been reduced in length from 75 inches to 63 inches, this work was carried...

A

Components of receiver group. Up-end the holt extension so that the firing pin assembly can drop out of the rear end. 4. Push out the sear plunger seat stop pin, then remove the sear spring seat and scar spring, taking care that these do not fly out when the stop pin is removed. 5. Push out the sear cover plate lockpin slide out the sear cover plate top and the sear cover plate bottom then remove the scar. To Strip the Firing Pin Unit. Clamp the special tool provided...

Action of the Breech Mechanism and Semiautomatic Gear

To open the breech by hand, place the tommy bar in the hole in the rack pinion and press it downward until the breechblock is held bv the extractors. As the rack pinion is actuated, it rotates the actuating shaft and also causes the rack to move upward and further compress the actuating spring against the spring cap. At the same time, the roller on the end of the actuating shaft, engaging the under side of the breech cam, lifts the breech cam which compresses...

Action of the Sear Mechanism

When the breechblock and striker frame move forward, the automatic sear mechanism holds the striker spindle in the retracted position. At this linie, the breechblock abuts the breech face of barrel. This movement allows the striker frame to continue forward. The breechblock, which up until now has been locked to the barrel extension, starts in counter-recoil when the cam of the striker disengages the automatic sear from the striker spindle. When' all operating parts have reached their...

Action of the Striker and Firing Mechanism

As the crank rotates to the rear on opening the breech, it travels in the concentric portion of the cockine link recess and no movement uf the breechblock takes place. The cocking link actuating pin, however, moving in the hole in the cocking link, forces the cocking link to the rear. The cocking link, engaging the lower arm of the striker sleeve, forces back the striker sleeve and striker spindle, compressing the main spring and withdrawing the firing pin inside the firing-hole...

Aden

The 250-volt condenser discharge circuit is satisfactory for use with the gun. However, the gun is unsuitable for controlled rate fire. A buffer and or locking unit for the slide would be necessary if controlled fire were desired. 13. Primer resistance in die British round is considerably lower than that of small calibcr American rounds (M52A3 primer). 14. Trunnion forces of approximately 7,000 pounds in tension and 15,000 pounds in compression can be cxpcctcd. Torque loads of approximately...

Adjustments

It may be necessary to make various adjustments to compensate for the normal wear of certain gun parts. The following instructions for making these adjustments shoidd be carefully followed. 1. The height of the sear roller in its depressed position should be approximately flush with the top of the sear block. With the cover opened, this should be checked in two ways. (a) Depress the sear roller with the manual release lever, and pull the bolt assembly to the rear. With the bolt held firmly down...

Aircraft Cannon

To load, the gunner inserts the cartridge belt into the feedwav until the stop pawls engage under the first cartridge, then loads the gun by performing two loading movements. During the first movement, when the gunner draws the crank back, the slide with its withdrawing pawl moves down and catches the first cartridge. When the crank moves forward, the slide moves up again and moves the cartridge belt over with it the stop pawls engage under the second cartridge in the belt the dividing pawl is...

Ammunition and Chamber Designs

The first ammunition to be used in the development was the standard 20-mm M90 series service rounds. Considerable difficulty was encountered in overcrushing the case during ramming. Rounds of ammunition were being rammed into a chamber at velocities of 80 to 100 feet per second. The chamber from the 20-mm automatic gun M3 was used in the first tests. It was found, after a small number of tests, that the rounds were going into the chambcr till the case itself was being engraved by the rifling....

Ammunition Received by Colt on July

A third lot of 200 rounds of ammunition reached the Colt plant on 10 July 1945. Particulars of this ammunition as shown on the data card arc as follows The B dimension on the first 25 of these cartridges ran from maximum 5.182 inches to minimum 5.165 inches. With this condition there would be no crushup on some of these cartridges.

Ammunition Used for Functional Tests of the Japanese Caseless

Only HE loaded ammunition was available no other type is known to exist. The ammunition appeared to be in a satisfactory state of preservation, although some rounds were slightly rusty adjacent to the base ends. Some verdigris had formed on the primers, but not enough to interfere with the functioning. The rounds were contained in a wooden box. Each round was provided with a plastic nose and metal base protector. The fuzes were located in holes bored in a tray bore in the box. Each fuze was...

Analytical Studies

Recoil calculations were made to determine the trunnion reaction, rccoil travel and rccoil time for various values of rccoil spring rate. These calculations were based on the following data Weight of powder 900 grains equal 0.1283 pound. Weight of recoiling parts 105 pounds (estimated) . Gas pressure at the muzzle 16,000 p. s. i. At the time these calculations were made, it was intended to limit the length of the weapon to 52 inches and to design ammunition with the same...

Arf Cannon

Feed pawls to push the round onto the ramp, the feed pawl slide trips the main slide latch. The main slide then moves back under pressure of its drive spring, carrying the feed pawl slide with it, and, by means of an overrunning clutch between the slide and sprocket, causes the sprocket to rotate and position the next round in front of the feed pawls. Analytical Studies. The following design and analvtical studies were made in connection with de-velopmcnt of the T33E3 model A weapon. 1....

Assembly

Assembly of Receiver and Tube Support. 1. Replace the feeder frame pins into their proper holes in the receiver. Drive out the 3 i -uich roll pins. 2. Replace the actuator slideways in the receiver base, alining the holes in the slideways with the holes in the receiver. Fasten the slideways to the receiver with the twelve J 4-inch socket-head screws. 3. Rcplace the switch camways in the receiver base, alining the holes in the camways with the holes in the receiver. Fasten the ways to the...

Assembly by Groups

Slip the adapter assembly on over the front end of the barrel support, with the trunnions toward the rear of the gun. Line up the keyway in the adapter with the locating key on the barrel support, and slide the adapter back until the full length of the locating key in the barrel support is covered by the adapter. Then start the adapter retainer nut on the threads at the front end of the barrel support and draw it up tight with the combination wrench. The adapter retainer nut...

Background

The 20-mm aircraft gun T55 (Mk 9) is an experimental gas operated blowback, belt-fed, pneumatically charged weapon developed from previous experimental guns, the T5o (type I ) and the T55 (type 2). This report covered the investigation of two T55 (Mk 9) guns which had been converted to fire electric primed ammunition. The 20-mm aircraft gun T55 (Mk 9) was an experimental single barrel gas operated blowback gun, which was modified to fire electrically primed ammunition. The profile dimensions of...

Background and Development

The Navy became interested in the possibilities of a larger bore automatic cannon of the type of the T33, and in 1950 a project was initiated. The prototype was made at the Naval Gun Factory under the official designation, 30-mm aircraft gun Mk 5 Mod 0. The Army designation for the same design is T120. In the same year, the prototype was delivered to the Naval Proving Ground, Dahlgren, Va., for test- General Data 30-mm Gun Mechanism Mk 5 Mod 0 Rate of fire 750-800 rounds minute (estimated)....

Basic Design

The design arrangement selected for the first test gun was a five-barrel model of medium size and performance suitable for construction as a development sample. The principal parts may be designated as Support feed unit housing bolt rotor barrel drive unit lock. The design follows the Gatling principle, which lends itself satisfactorily to the application of modern ammunition and electrical control. Where there is duplication of parts, like the bolts and bands, other items like the recoil...

Bofors

The spread of the Bofors mechanism throughout the world. Figure 22-2. The spread of the Bofors mechanism throughout the world. the Bofors Arms Co., the latter company became interested in the perfection of a 40-mm gun that could be used on shipboard as a defense against aircraft. The gun that was developed stemmed from the 40-mm cannon originated by the Krupp Works. The Chief of the Bureau of Ordnance became interested in diis gun through the efforts of an American businessman, Mr....

Bolt head assembly

Guiding the cartridge toward the chamber. With the sear roller depressed, the bolt assembly moves forward. The top front edge of the bolthead hits the base of the cartridge and moves it forward, stripping it from the link. The cartridge is guided downward toward the chamber through the front end of the slot in the fccdwav assembly by means of 3. When the forward motion is completed and the cartridge is held securely in the chamber by the bolthead assembly, the bolt pushes the tip...

Breech Mechanism

The breech mechanism can be dismantled and assembled with the gun installed in the aircraft. Dismantling the Breech Mechanism. Apply the tommy bar to the rack pinion and open the breech by pressing the tommy bar downward. Set the safetv catch to SAFE, withdraw the re- taining catch plunger, rotate the striker through an angle of 60 to the right, and remove it from the breechblock. Take the weight of the actuating spring by pressing the tommy bar downward, release the extractors from...

Breech Ring Assy Bolt Head Roller

Beginning of locking action. assembly and buffer spring, thus producing automatic firing. When the next cartridge is within about 5 ir, inch of being chambered, the bollhead rollers contact the breech ring cams. This gives the bolthead a chance to begin rotating in preparation for locking to the breech ring assembly. While being rotated by the breech ring cams, the bolthead continues its forward travel and chambers the cartridge. After the cartridge is fully chambered and the...

British mm cannon

Actuating shaft, crank, striker cocking link, rack pinion, actuating shaft sleeve, spring case, rack, and breechblock actuating spring. The actuating shaft is mounted in bearings formed in the underside of the breech ring, being retained in position by a slotted nut and split pin at its right-hand end. The left-hand end of the actuating shaft is cranked and carries a roller which engages the semiautomatic cam and breech cam on runout. Cut along the shaft for the greater part of its length are...

Browning

A turning point in the development of the highspeed gun was the advent of the T22E6, although the initial tests of tills model were discouraging. On 13 December 1943, two T22E6 guns were fired 400 rounds and 1,000 rounds, respectively. Cracks developed in the new lighter bolts supplied with the guns. New bolts were made, and the guns refircd on 29 December 1943 with the following results Gun A 5.000 rounds fired average cyclic rate, 1,160 7 breakages causing 6 malfunctions. Gun B 5,000 rounds...

Browning Cal

If the bolt latch release is held dowTi manually or if it is locked down by the lock on the buffer tube sleeve, the gun will fire automatically. However, if the bolt latch release is pressed dowrn but not retained in that position, the gun will fire only once when trigger action is given. The backplate spade grip assembly is similar tc that used on the aircraft gun except for the addition of the buffer tube sleeve assembly and the bolt latch release and spring....

Browning Mm

Depress the tube lock because it must snap into the groove in the tube just as the shoulder contacts the tube extension. Check this lock engagement by looking through the sighting hole. Caution, lube should thread into tube extension freely. If it docs not, do not force it with the wrench. Remove the tube arid examine threads on tube and in extension for burs or rough spots, which should be removed with a line stone. Note. If the recuperator piston rod nut has been removed or loosened during...

Cal Short Recoil

German Mauser 20-mm Automatic Gun MG-151 20. Figure 4-1. German Mauser 20-mm Automatic Gun MG-151 20. minor design changes. New links were provided by the Autovrc Co. The first test firing of the gun was at the Colt plant on 23 November 1942. It was found that the recoil was very heavy and that extraction was too early as evidenced by expanded cases. It was assumed bv the designer that the rate of fire was much above the desired rate, and a recoil brake was added to the muzzle....

Caliber T Model D

Volving drum, containing five cartridge chambers parallel to its axis of rotation and mounted upon a shaft within the drum support, so that each chamber is brought into alincmcnt with the bore of the barrel and momentarily stopped when it reaches the 6 o'clock position during drum rotation. The barrel is housed in a tube support attached to the front end of the receiver and is retained by interrupted screw threads and a latch in the front end of the drum support. When assembled to the receiver,...

Cleaning

All parts should be checked to insure that they arc clean and lubricated. If not. clean according to the directions in the following paragraph. Thorough cleaning after firing is extremely important and should be performed as soon as possible. The bore and other portions exposed to primer fouling should be thoroughly cleaned of primer salts, using rifie bore cleanser. The corrosive primer salts are water soluble but are not soluble in petroleum distillates. Barrels. Except, in emergencies,...

Colt Mm Cannon

A feed way located in the forward end of the receiver and resting on the side plates immediately under the feed slide unit forms a channel through which the cartridges loaded in metallic links pass into the gun. A deflector plate, located over the fecdway, acts as a guide, giving the necessary downward pressure to the cartridge and insuring that it enters the chamber correctly. Two stripper cams are positioned in the feedway, the cars of the cartridge metallic links being carried on guides...

Conclusions

The conclusions reached were stated as follows 1. That operation of the 20-mm Shirgun by the short recoil principle is feasible. 2. That a mockup gun so modified at NAOTS has successfully performed the function of unlocking, extracting, cocking, loading, and locking by recoil and counterrecoil force. 3. Principles involved in changing this weapon to a short recoil system in lieu of gas operation are basically sound. 4. The method employed in pinning down the breech lock on a cam insures...

Confidential

Give a comprehensive picture of the gun and feeder in operation. Jump cards of the ground mounted 57-mm gun were fired at a 500-yard target. Two firings were attempted. On the first, the sighting point was too low and one shot was lost. The data for the sccond target is as follows 80 percent circle 2.5 mils diameter. 100 percent circle 3.9 mils diameter. Air Firing. Air firing was started on 6 July 1945. A total of 240 rounds were air fired. Four rim-lock stoppages occurred in six flights then...

Confidentialbritish Mm Cannon

Comparative Data Loaders, Ammunition, and Mountings for 6-Pounder Class M 57-mm British High- Velocity Field Gun and 75-mm Aircraft Gun AN-Mk 5 (T31E1) 23 rounds 1 21 rounds carried in racks. Electrical and mechanical Hand loaded. 322 pounds Weight allowed for crewman 170-200 pounds. 32 inches Not pertinent. Overall length Height, maximum, with breech open and pusher arm up. 129.24 inches. No data available. Do. or installed. A blister is formed in the panel and in the forward part of the...

Confidentialcal Go Short Recoil

Pin beyond the fare of the bolthead to strike the primer and fire the cartridge. Feeding and Ejector Group. The feed way and ejector group is mounted in the top forward portion of the receiver and is held firmly in position when the cover is closed. The group consists of the feed-way and ejector assembly and the cartridge stop assembly. When the empty case is extracted from the chamber and carried rearward by the bolt assembly, it strikes the ejector, which is mounted on the rear of the...

Confidentialcolt Mm Cannon

V.-.V ' ' '.V.V V.-.V ' ' '.V.V Figure 9-12. 20-mm Gun T24. Top view of bolt. entered in its hole in the bolt extension. Tush the lock pin home. 4. Replace the firing-pin assembly in its hole in the bolt extension. lip-end the holt so that the rear is to the top and the firing-pin assembly will drop until stopped by the shoulders of the sear. Push in on the sear to allow the firing-pin assembly to go fully forward. Insert the firing-pin spring stop pin and insert the lockpin, pushing it home....

Confidentialhispanosuiza

British Hispano-Suiza Guns, top to bollo.-n Mark I, Mark II. Mark V. General Data British 20-mm Automatic Gun Mark V Rate of fire 700 750 rounds minute. Barrel removal Cannot be removed easily in field. System of operation Gas unlocked, blowback assist. System of feeding Automatic spring-wound feeder em Method of headspaee No provision made for adjustment. Location of feed opening Top of receiver. Pitch 7 (equals 1 turn in 25.587 calibers and 1 turn Location of ejection opening...

Confidentialjohnson

The 20-xrun loiiiison Automatic Cannon mounted on a test stand firing Oerlikon ammunition. power to do all the work as possible. Hcncc the gas-timed, self-unlocked, retarded blowback plus gas actuation system. In other words, there were two forces available to do the total work required of this gun, the gas piston force and the residual pressure force. This gun, especially the 3rd model, took some of its feed features from the Browning machine gun. During the summer and fall of...

Confidentialrollsroyce

Rolls Royce 40-mm Type BD Naval Gun. Barrel and components of breech ring. The breechblock body is of rectangular section and has an axial cylindrical hole to accommodate the striker housing. The striker housing is retained in the breechblock body by two floating cams which permit a limited relative axial movement between breechblock body and striker housing. The sear is pivoted in the breechblock body and engages the striker contained in the striker housing. The striker housing...

Confidentialshirgun

The feed of the original 20-mm Shirgun. was experienced in function firing the first versions of the low profile type, the main difficulty being the breakage of brccch locks in a comparatively few-rounds. The Shirgun program was discontinued in 1949. However, the project was revived as the 20-mm machinc gun mechanism EX 5, and in the fall of 1953 it was in the blueprint stage. Along with the EX 5, a program of converting the Mk 13 Mod 0 to 30-mm was initiated and given the official...

Contact Assembly Adjustment

Remove the insulation washer, spring, and stop from the contact. 3. Insert a 4-inch dowel pin into the contact and place a dial indicator on the housing such that it will read the travel of the dowel pin. 4. Rotate the rotor in the running direction noting the reading on the dial indicator as each slide passes under the contact. This travel should read 0.010-0.020 inch. If not, remove a shim from under the contact or replace the contact button.

Conversion from Right Hand to Left Hand Feed

The following parts are either changed or reversed in assembly for conversion from right-hand feed to left-hand feed. Switch Cam. A different switch cam is used for left-hand feed to provide clockwise rotation of the drum. Rammer. The right-hand feed rammer must be replaced with one made for the left-hand feed. For left-hand feed, the rammer is located on the right side of the slide. Extractor Striker. The extractor striker is replaced with one made for left-hand feed. Its position for...

Cover Latch Assembly

COV R HiNOt ASSEMBLY ADAPTER CROUP---- l FEZVWiY A O EJECTOR GROUP RECEIVER AND BARREL SUPPORT GROUP Figure 4-7. Gun, Machine, Caliber .60, T17E5. General assembly of groups. A hardened barrel liner has been provided to lengthen the life of the barrel. Three knurled bands down the middle provide a convenient gripping surface when assembling the barrel. An enlarged fluted section to the rear of these knurled bands slides within the barrel, bearing the recoil and counterrccoil of the barrel. The...

Curtailment Following World War i

The commission laid down the activities that were permitted in the field of armaments. The curtailment imposed caused a lean time for the firm even though it turned to the manufacture of agricultural machinery. Some of the personnel went to Switzerland to firms such as Oerlikon and Solothurn. In 1929, Rheinmctall established a subsidiary company in neutral Holland under the name of Hollandische Industrie and Handels Mattschaps (HIH). This venture turned out to be unsatisfactory however, in the...

Cycle of Operation

The '145 machine gun is operated in two steps (1) closing the master switch and (2) closing the firing trigger. Closing the master switch energizes relays which set the brake and start the drive motor. Note. These relays are not an integral part of the T45 machine gun, although they may be supplied in a test control hox. The motor brings the flywheel up to speed. After the motor and flywheel combination are brought to speed, the gun is ready for firing. On closing the trigger, the solenoids...

Description

This weapon was designed to use the new 20-mm, 3.500-fcct-per-second T5E1 round. Sincc this round has a much larger case than the standard one, the T24 chamber is larger and the receiver 2l 2 inches greater in diameter than the T22 gun otherwise, the two guns are identical in construction. It is short-recoil operated, has right- or left-hand feed without extra parts, forward sear, bolt holding back sear, mechanical feed for link belt, and quickly detachable barrel. The weapon can be operated by...

Description of Components

The gun barrels arc quickly dctachcd by raising a spring-loaded detent and rotating the barrel through one-sixth of a revolution. The rifling of the barrels is machincd to engrave the rotating band with straight rifling and then progressively increase the twist so that a constant angular acceleration is applied to the projectile for the full length of the barrel. Pneumatic Tank. The pneumatic tank acts primarily as a reservoir for the pneumatic ejection, Mounting. The pneumatic tank is...

Description of Material Tested

The 20-mm Shirgun EX 1 type 1 (prototype) is an automatic, gas-operated aircraft weapon, with a semi integral feed mechanism. The overall length, with the ()7.5-inch barrel, is 89.5 inches the maximum height, with the feeder installed, is 7.25 inches and the maximum width of the receiver is 7 inchcs. The addition of a pneumatic or hand operated firing mechanism which was supplied with the guns, on the side of the receiver, increases the maximum width to 8 inchcs. The barrel is the same as is...

Description of Tests

Upon receipt of the first four guns, a measurement check was made of all the parts against a complete set of Shirgun drawings that were furnished by the Naval Gun Factory. All springs were calibrated at the lengths specified by the drawings and recorded. Barrel rifling and chamber measurements were also made. A set of drawings was maintained throughout the test for each one of the guns and any substitution or change in the parts of the gun was rccordcd on the set of drawings for the gun or on a...

Description of the Browning Machine Gun Caliber M Aircraft Basic

This is a highly efficient automatic weapon built to precision standards, ft. is air-cooled and may be fed from either the right or left side. It may be mounted on cither a rigid or flexible mount. Manual cocking and loading of the gun is necessary before it is ready to function automatically. Then it may be fired by a mechanical or electrical accessory or by a manual trigger and trigger bar. While firing, all mechanical action is automatically performed by the gun itself. The receiver and...

Description of the MG

The German gas-operated gun MG-213, upon which the development of all models of the revolver-type of automatic cannon developed by the United States was based, is a gas-operated, belt-fed, electrically fired, pneumatically charged weapon which fires at a rate of approximately 1,200 rounds per minute. i3y changing certain parts, it may be con verted from a 20-mm to a 30-mm weapon by reversing certain components, it may be changed from left-hand to right-hand feed. The distinguishing feature of...

Description of the Weapon

The MK-103 is a 30-mm automatic aircraft cannon that is gas operated and air cooled. A steel cartridge belt feeds the weapon from the top. A metal disintegrating link is employed. The locking action is practically identical with that of the experimental American automatic cannon that never advanced beyond the limited-service use, namely, the Navy's 1.1. The weapon was made in two different types. One is an engine-mounted gun with a shrunk-on inner liner, which is assembled from the rear the...

Description of the Weapons

Known officially as the SG series (Sunder Gerat or special purpose equipment), these weapons were developed at the Herman Goering Werke at Brunswick. They never advanced beyond the developmental stage. These weapons were designed in various calibers on the principle of the Davis gun and were recoilless. The most popular version was the 7.5-cm sabot type projectile having a 4.5-cm AP core that was fired out of one end, and an equal weight that was shot out of the other. The two elements were...

Design and Description

While the 20-mm Automatic Gun T74 Model B was being manufactured, design of another model was initiated. This model was initially designated T74 Model C and later redesignated T110. In designing this weapon, emphasis was placcd upon reduction of weight and reduction of overall dimensions to meet the following limitations specified by the Ordnance Corps In order to meet the maximum silhouette requirements, major changes in the arrangement of components were made, and whenever possible these...

Designations and Characteristics of Various Models

In September 1950 four more ilA prototype guns were proposed to be used by the Ordnancc Corps and Air Force for engineering tests and installations. Two additional models, designated B1 and B2, to include refinements due to testing of the A5' models, were to be made. Twenty-five additional models, designated C53, to be made with temporary production tools were scheduled. An ammunition booster mounted on an ammunition container of 200 rounds capacity was designed and fabricated. The booster was...

Designations

40-mm Machine Gun Mechanism Mk 4 Mod 0. This is the Mk 2 Mod 0 with feed modified by the Shirgun Corp. 40-mm Machine Gun Mechanism Mk 4 Mod . This is the Mk 2 Mod 1 with feed modified by 40-mm Machine Gun Mechanism Mk 5 Mod 0. The 40-mm single-gun mechanism M1 installed on mounts M3 for Navy use was procured for the War Department from Chrysler Corp. Slight modifications, such as difference in paint and buffer fluid were made to the mcchanism Ml to adapt it to Navy use. The arrangement required...

Detail Description

The weapon consists of the following components gun barrel, gun mechanism, rccoil mechanism, receiver, breechblock, cradle, charger, gas mechanism, and buffer assembly. Gun Barrel. 20-mm gun barrel, Mk 11 Mod 0 is a tubular alloy steel forging. Threads on the breech end of the gun attach it to the receiver. A locking pin hole on the under side of the breech end is engaged by a locking pin in the receiver assembly, preventing rotation of the gun barrel after assembly with the...

Detailed Disassembly

Remove the feeder shaft through the front of the feeder. This releases the sprockets and guide tracks for removal. Remove the front end and the rear feeder shaft bush ings. The internal guides and chute may be disassembled by removing the appropriate socket-head 2. Relinking Feeder. Remove the feeder shaft through the front of the feeder. This releases the sprockets and guide tracks for removal. Remove the front and rear feeder shaft bushings. The center and...

Detailed Disassembly and Assembly

In the following description of the detailed disassembly and assembly of the gun groups, it is assumed that the ordnanceman is familiar with the operations involved in removal and installation of groups as a whole. 2. In disassembling the gun, it will be found helpful to place the parts neatly in order as they are removed. 3. Place disassembled parts on a clean, flat surface and guard against loss of pins, springs, and other small parts. 4. Parts for each gun should be kept intact and separated...

Detailed Maintenance of Buffer Assembly

To check the buffer action, bleed the air pressure by loosening the bleeder plug on the left rear end of the buffer housing. 1. Check free movement of the piston. If it binds or sticks excessively, replace the buffer. 2. Check the buffer lock plunger. 3. When the buffer is disassembled, check to see that the O-ring is not worn or broken. Cleaning and Lubrication. When disassembled, precaution should be taken to prevent any dirt or foreign substance from entering the housing. The parts, before...

Detailed Maintenance of Charger

Careful maintenance of the charger is very important. A faulty charging system may cause loss of use of the gun in combat. Cleaning and Lubrication. Since most of the working parts arc totally enclosed, cleaning and lubricating arc essential only when the charger is disassembled. 1. Give a very close inspection to the internal parts for presence of any foreign material in the air port or on the tube internal surfaces. 2. Inspect the condition of all O-rings and backup ring3 for wear or...

Detailed Maintenance of Gas Mechanism

Maintenance of the gas mechanism is exceedingly important to insure the proper rate of fire 1. Check the sleeve assembly. If bent, replace. 2. Check the gas cylinder sleeve spring. If set or broken, rcplacc. 3. Check free movement of gas cylinder sleeve assembly on the guide. Tf binding, replace the guide or sleeve. 4. Check the gas cylinder vent plug for erosion or fouling. If eroded, replace the gas brackct. If fouled, clean and reinstall. 5. Remove light burs from the piston end of the...

Detailed Maintenance of Gun Barrel

Bore wear depends upon cleaning, preservation, cooling between periods of firing, and number of rounds fired. Whenever possible, the bore should be examined for foreign material, including copper fouling and propellant residue, deformation of lands or grooves, indentations resembling pits in castings and pitting of the lands or grooves. It is not necessary that the bore be shiny to be clean. A clean bore may have a dull, gray appearance. Before-Firing Maintenance. Wipe the bore clean if no...

Details of Test Procedure

After inspection and repair of the gun, as received from Kngland, testing was started. The procedures followed are discussed by test item or subject as follows Rate of Fire. Individual and overall rates of fire were recorded by camera chronograph during all test phases. Rounds were magnetized and fired through 20-inch solenoid coils. Dispersion and Yaw. Dispersion and yaw were taken at 1,000 inchcs by firing through cardboard targets during all phases. A plastic scale prepared from measurements...

Development

In June 1945, Ordnance Committee action was taken to authorize the requirement for a 1,500 rounds-per-minute caliber .50 machine gun. Subsequent to this authorization in July 1945, a contract was placed with the Frigidaire division to provide for a continuation of the development of the M3 (T25E3) gun in an effort to increase its cyclic rate to 1,500 rounds per minute. Limited firing has been conducted on this gun, designated T38, at cyclic rates of 1,450 to 1,500 rounds per minute, but the...

Development and Tests

Currently with the development of the T22E6 gun, an attempt was made by the High Standard Manufacturing Co., to provide a kit of parts which could be used to convert the standard M2 gun to a high-speed weapon. The designation given this gun was caliber .50 T27E7. Experiments for the purpose of producing this high-speed weapon were carried on under the scries No. T27. The first two guns of this series were submitted to Aberdeen Proving Ground for test 1 January 1944. The tests of both guns were...

Development of the T

In December 1943, Colt's Patent Fire Arms Co. began development of an experimental gun designated the 20-rnrn automatic gun T22. The design was to be based on principles of operation found in the recently captured German Mauser MG-151 20 but to utilize the movement of the bolt to operate the feed mechanism. The requirements were set up as follows That existing ammunition for the 20-mm M2 gun should be used for initiating the project that the feed mechanism be of the disintegrating link-belt...

Development Programs for the T T and T

The earliest two guns of the caliber .50 Browning design, which were constructed in the year 1918, fired at a cyclic rate of 500 rounds per minute. Improvements of these weapons resulted in the Ml921 aircraft gun, actually standardized in 1923, and the M1921 water-cooled gun which was officially adopted in 1925. Only a small number of each were procured. These weapons had a nominal rate of fire of 500 to 600 rounds per minute but were handicapped by their being able to feed only from the left...

Development Work for the Armed Services

Earlv in 1942 the Bureau of Ordnance initiated a 20-mm aircraft machine gun program for the pur- Figure 10-2. Senate Military Affaiig Committee meeting of 2 July 1940. Left to right Senator Morris Sheppard, Chairman of Committee Maj. Gen. George A. Lynch, Chief of Infantry (standing, left) Brig. Gen. R. C. Moore, Assistant Chief of Staff, United States Army Melvin M. Johnson, Jr. Senator A. B. Chandler (seated far right). The Johnson semiautomatic rifle Yfas discusscd at this meeting.

Disassembly

The procedures given in this section apply to both To disassemble the gun into subassemblies, proceed as follows 1. Open the cover. Press in on the cover latch release. The gun will then be ready for disassembly. 2. Remove the cover. With the cover down and using a screwdriver blade, turn the cover joint pin so that its locking catch disengages from the slot in the deflector plate. Push in on the covcr latch release to relieve pressure on the joint pin, then remove the joint pin and cover. 3....

Disassembly by Groups

The major groups of the gun are the barrel, cover group, bolt group, feed way and ejector group, adapter group, and receiver and barrel support group. It is assumed that the gun is set up for right-hand feeding. Caution. Before starting to disassemble the gun, make certain that it is not loaded. Follow the instructions sent with cach gun giving procedure and detail for assembly and disassembly. Barrel. Depress the rear end of the barrel lock and turn the barrel about one-fourth turn...

Discussion

Considerable difficulty was experienced during the early stages of the test arid also to a lesser degree throughout the test, in regard to maintaining a complete set of approved gun drawings. As a result of discrepancies in and changes made to the original drawings a standard sketch list of drawings was established as of 1 November 1946. Due to the many changes made in gun part design by all agencies engaged in the test work it was not possible to maintain an accurate approved list of sketch...

Early Design Problems

The necessity of quick starting of the gun without undue stresses on the ammunition belt and the matter of clearing the gun for prevention of cook-offs have necessitated the use of certain control auxiliary which would not have been otherwise required. It was early determined that, in a gun of the proportions that existed in this type of mechanism, it would be possible to store sufficient energy in a small flywheel to permit starting of the gun rotor in a satisfactorily short space of time, 0.1...

Ex Type I Gun No

In October 1946, the Bureau of Ordnance directed that the Naval Proving Ground conduct proof firing tests of five 20-mm machine gun mechanisms EX 1 type 1. In addition, the Bureau directed that experimental ground firing tests be conductcd on 3 of the 5 guns the other 2 guns were to be shipped to the Shirgun Corp. upon completion of proof firing. The experimental ground firing was for the purpose of obtaining functional firing data on all components of the guns, life of parts, etc. Specific...

Field Stripping of the Second Model

Field stripping should require no longer than 1 to 2 minutes. 1. Raise the barrel clamp lever. 2. Rotate the barrel clockwise 60 and withdraw toward the front. 1. Press in the mainspring guide shaft and rotate 90 in either direction. 2. Withdraw the guide and spring. 3. Withdraw the locking plunger from the buffer plate and lift up and remove the buffer assembly. To Remove the Breechblock and Operating Shaft Assembly. 1. If it is not already cocked, grasp the cocking handle, hold the...

Firing

Set the change-over switch at E. Ever)' round is fired by a separate pressure on the trigger. A pressure on the trigger forces the trigger back so far that it strikes against the changeover switch, whereby the forward-pointing arm of the trigger draws the trigger rod depressor down by means of its hook. The trigger rod depressor draws down the trigger rod, disengaging the trigger rod lug from the notch of the percussion arm. The percussion arm, under the influence of the...

Firing on August

The modifications having been carried out, this third lot of ammunition was lest fired at the Colt plant. Test 34. Gun had a solid ejector (type 3) with fiber insert. Tube had chamber modified to afford increased support to the cartridge case. Separator was in gun. Round marked 52 was placed in the chamber, and the following dimensions were taken Cartridge head protrusion 0.191 inch. Dimension A (chamber) 5.188 inches. Dimension B (cartridge) 5.180 inches.

Firing on February

Owing to difficulties experienced due to faults in the ammunition composing the first lot of 25 rounds received, a further lot of 25 rounds for tests was sent from Pic a tinny Arsenal. These cartridges had the following characteristics according to the data card accompanying the consignment. Expected pressure 51,400 p. s. i. Muzzle velocity 3,500 feet second. Weight of charge 863 grains. Powder 4,879 I. M. R. The cartridges were measured on the B dimension and the results tabulated. The B...

Firing on March

Ejection was tested using wire type ejector (wire diameter 0.062 inch). Round marked 12 was placed in the chamber, and the following dimensions were taken Cartridge head protrusion 0.175 inch. Dimension A (chamber) 5.188 inches. Dimension B (cartridge) 5.171 inches. Round fired correctly but did not cjcct. The following particulars were noted from this firing Total time for cycle (estimated) 0.076 second. The wire ejector was found to be deformed after this test. Rate of fire...

Firing on

Testing with a new bolthead cut away at the top for cartridge entry. Using Type 2 ejector (medium length). Round marked 24 was placed in the chambcr. The following measurements were taken Cartridge head protrusion 0.176 inch. Dimension A (chambcr) 5.188 inches. Dimension B (cartridge) 5.172 inches. Cartridge fired correctly but did not eject. The following particulars were recorded from this firing Rate of fire was not recorded. New bolthead appeared satisfactory. Test 28. Test with...

Firing on May

Test using ejector type 1 (medium length) modified by having pivot point advanced 1 inches in the ejector bracket. Round marked 17 was placed in the chamber, and the following measurements were taken Cartridge head protrusion 0.185 inch. Dimension A (chamber) 5.188 inchcs. Dimension B (cartridge) 5.184 inches. Cartridge fired and ejected correctly. The following particulars were recorded from this firing Recoil time 0.028 second. Counterrecoil time 0.046 second. Total time for cycle...

Firing Tests

The following statements are taken from a report of firing tests conducted at Naval Aviation Ordnance Test Station, Chincoteague, Va. 6 November 1951. The gun was partially disassembled for a general visual inspection. The cam slots in slide in the breechblock assembly were deformed slightly as a result of previous firing. The slide was then ground to remove burrs and sharp edges to insure proper functioning. In the rammer and buffer assembly, a tightness was discovered between the buffer anvil...

Fixed Gun Installations

The muzzle energy of the 40-mm S gun is about eight times that of the 20-mm Hispano-Suiza gun but since the rate of fire is only about 100 rounds per minute and the recoil stroke is about 17 inches, the time available for the dissipation of the recoil energy is about seven times that of the Hispano-Suiza gun. Thus, the recoil forces and mounting loads arc of a lower order than with the 20-mm gun, but the duration is much longer. The problem of mounting this gun in an aircraft was therefore a...

Free Gun Installations

The only free gun installation of the 40-mmS gun was in a turret designed by Vickers Armstrong Ltd., in a Wellington in the mid-upper position. This was a hydromechanical, fully rotating turret mounting one 40-mm S gun and equipped with rangefinder and redictor. The turret never went into production or service, but it is fully described in a report by the testing activity. These guns were mounted beneath the wings at an angle that prevented the muzzles from being seen by the pilot gunner. Even...

Functional Investigation

On 26 September 1949, the Naval Proving Ground issued a partial report on the functional investigation and development of the 20-mm aircraft gun T55 (Mark 9). As directed, the procedure followed in this investigation was in accordance with that established bv the Aircraft Guns Test During the period covered by this partial report, 1,820 rounds of percussion ammunition were fired. In the investigation and development of the T5) (Mark 9) gun, 243 malfunctions and stoppages occurred. The...

Functioning of the Browning Machine Gun Caliber M

Although this gun is an automatic weapon, it is necessary to cock it manually to start the operating sequence. Assume that the gun is cocked and that the first cartridge is in its firing position in a chamber in the rear portion of the gun barrel. When any cartridge is fired, the burning powder violently generates gas which, since it is confined by the cartridge case and barrel, exerts a tremendous pressure. This pressure reachcs 50,000 pounds per square inch, and sincc this pressure pushes...

Functioning of the Second Model

The second model aircraft belt-fed machine cannon by Johnson Automatics, Inc., is a belt-fed automatic gas-operated type weapon, rooled by air. The primary source of operating power is derived from the impingement of the gases against the gas piston, taken through the gas port located as near as practicable to the breech. The position of the gas port is governed by the pressure curve and timing of extraction, since premature extraction would necessitate lubricated ammunition, or...

Fuselage Installations

Early in 1941, before the Hurricane installation had reached the test stage, the possibility was contemplated of using 40-mm guns in the fuselage of the Beaufighter. An installation was prepared by the British aircraft armament group in collaboration with Bristol Aeroplane Co. for mounting two 40-mm guns in the position normally occupicd by the 20-mm guns. This installation was designed to mount one Vickers S gun and one Rolls-Royce type BH gun for the purpose of comparing the performance of...

General Description

This weapon is intended lor both air-to-ground and air-to-air combat. Rach installation comprises 20-mm gun mechanism Mk 11 Mod 0, 20-mm gun barrel Mk 9 Mod 0, and 20-mm gun barrel Mk 10 Mod 0. The gun mechanism consists of the following components receiver assembly, pneumatic tank assembly, breech assembly, sprocket assembly, and cylinder. General Data 20-mm Gun Mechanism Mk 11 Mod 0 With Mk 9 barrel, overall 52 inches. With Mk ID barrel, overall 70 inches. With Mk 9 barrel (short) 162 pounds....

General Principles of Operation

The general principles of operation of the gun are as follows 1. The barrel, breech ring, body, breechblock, and recuperator mechanism constitute the recoiling parts. 2. The cradle, recoil shield, main recoil ram, hand loading tray, shoulder piece, and sights do not recoil. 3. The breechblock is closed by pneumatic pressure. 4. The breechblock is positively locked before firing. 5. The striker is inoperative until the breechblock is locked. 6. Energy of recoil is absorbed by a hydropneu-matic...

Gun Mechanism Mark

Various types of mechanism were investigated. 1. Propellant gas driven multiple piston versus single piston and cam. (a) Short recoil (this stopped most designs). (b) All early methods of multiplying rccoil motion became cumbersome. ( r) Multiplied motion with cam reciprocating and rollers on cylinder. (d) Multiplied motion by use of a linkage with the rollers reciprocating (the most satisfactory). The system to control recoil motion and belt feeding by use of cams on the rotating cylinder and...

Head Assembly Ring Assembly

Bolthead locking lugs of Caliber .60 T17E5 Machine Gun. through the projection at the rear of the bolt is to provide clearance for the cjector when the bolt assembly is in its forward position. The complete cycle of the recoiling portion of the gun, which takes place as each cartridge is fired, consists of the recoil stroke, when certain parts of the gun move rearward, and the counterrecoil stroke, when these same parts move forward. At the instant of firing, the recoiling portion...

Heavy Barrel M

The Browning machine gun, calibcr .50 FIB, M2 is an air-cooled gun for ground use, having a much heavier barrel than has the aircraft gun. The gun is normally fired in short bursts or in rapid single shots, and when used in this manner firing may be continued for an appreciable length of time because the heavy barrel retards overheating. Tn place of the barrel jacket assembly 011 the aircraft gun, this gun uses a short, perforated barrel support. The trunnion adapter of the aircraft gun is not...

Hisp Anosuiza

Use the new type of vent plug (larger vent hole) which can be identified by the part number stamped on its face. 5. Remove all carbon and any other foreign matter from cylinder, piston, brackct, and plugs. 6. Remove burs from piston if not burred excessively. If it is excessively burred, replace gas cylinder sleeve with piston. 7. Check movement of push rods in their rcccsscs in the receiver. Remove all burs from push rods. Gas Cylinder Sleeve Group Maintenance by Ordnance Maintenance...

Hispanosuiz A

Remove pin from the slide spring plug pin and bolts. 2. Unscrew the slide-spring plug from the bolt. The slide spring will fall out. 3. With the rear of the bolt held against a soft surface, such as wood or cardboard, use a screwdriver to pry the left-hand slide away from the bolt. The rear slide key, which is pinned to the left side, will come with it, and the firing pin spring plug will be ejected from the bolt. 4. Remove the firing-pin spring. 5. Pry the right-hand slide away from the bolt...

Hispanosuiza

Shock and bring the breechblock to a stop. At this time, the rear buffer springs and the driving spring expand, forcing the breechblock forward. Magazine Slide. The magazine slide has a guide on each side. These guides provide for sliding engagement with corresponding guideways on the receiver. The feed mechanism is ecurcd to the magazine at the front by two hook-shaped projections on the slide, and at the rear by the magazine slide latch. The ejector fits into the lower two grooves in the...

Hispanqsuiza

Placc the driving spring over the tool and plunger. Insert the driving spring guide into the driving spring so that it fits over the tool. 6. Insert the assembled unit into the receiver through the opening of the rear buffer, making certain that it slides into the bore of the breechblock. 7. Placc the rear buffer wrench on the guide, press the guide in until it contacts the rear buffer, and then turn the tool to screw the euide into the buffer. 8. Bend the rim of the retainer on a flat of the...

History and Background

In 1936 the British commission became interested in the Hispano-Suiza Birkigt type 404. Negotiations for the purchase of six of these cannon by the British were completed in 1936, and the first gun was delivered in January 1937. Early in 1937 the Hispano-Suiza Co. proposed the establishment of a Hispano-Suiza plant in England if given a token order for 400 cannons. This plant was opened in December 1938 under the name of British Manufacture & Research Co. The British produced gun was called...

Huh

British 57-mm Automatic Aircraft Cannon. Vertical view of round in feeding position. mpr slide and the raniiner slide is engaged and held by the release pawl.) The gun continues to recoil but no further movement of the above components takes plat e. Action of the Feed Mechanism During Runout. During the first part of runout, no movement takes place in the feed mechanism. When the gun is about 14 inches from the firing position, the feed arm shaft roller commences to ride up the...