Month: January 2010

Categories
German

17 cm Steel Cartridge Case, Spiral Design

17 cm Steel Cartridge Case, Spiral Design

This is a large caliber steel cartridge case of different design from those customarily used by the Germans. The body is a wound cylinder made of 0.084 inch thick sheet steel three and four turns thick and turned under at the base to fit into a base assembly. The base assembly is provided with a retaining plate, screwed collar, and a disc which seals the cartridge case and prevents the escape of gases through the base. The disc is of cardboard; all the other parts are of steel.

A shallow spiral groove, about 0.003 inch deep and .23 inch wide, is rolled into the inner surface of the body under such pressure as to show the marks of the groove on the outer surface of the case. A layer of black wax is used between the overlapping coils of the body to assist waterproofing. The upper surface of the cardboard disc is also covered with black wax. It appears that this case is manufactured by coiling the sheet approximately to shape, placing the body in a die and rolling to shape with an internal roller. The base, retaining plate, and screwed collar have completely machined surfaces. All the parts have a thin surface film of oxide for protection from corrosion. This is not completely effective.

The Vickers Diamond Hardness of the body increases from about 105 near the base to 133 near the mouth. It is approximately 222 across the base except in the primer boss where it is about 280. On the retaining plate the V. D. H. varies from 160 at the center to 172 on the rim. The screwed collar is 175 V. D. H.

German: p. 314

Categories
German

Cartridge Case for 10.5 cm Recoilless Gun

Cartridge Case for 10.5 cm Recoilless Gun

The German Recoilless Gun, versions of which are described on pages 110 and 119, operates without a recoil or counterrecoil mechanism. This is made possible by a design which allows the propelling gases to escape to the rear when the weapon is fired. This unusual design of brass coated steel cartridge case, which makes possible an unexpectedly long range for such a weapon, is provided with a primer in its side and a plastic base insert. This plastic base insert, 1.12 inch thick, momentarily withstands the pressure of the ignited propellant and then disintegrates, being blown out the rear of the weapon along with the released propellant gases.

The propelling charge and igniter are made up to suit side ignition. The propellant is contained in a cylindrical bag; the igniter bag is in the form of a cap, and fits over the end of the propellant bag. The igniter composition is contained in pockets formed between the outer fabric and the lining by quilting the bag. There are twelve pockets around the side and six in the end. The propellant is a flashless composition of the normal “Gudol” type and the igniter composition is the normal porous chopped cord.

SPECIFICATIONS

Propellant weight      6.9 lbs.
Propellant analysis
   Nitrocellulose (N-12.34%)34.47%
   Nitroguanidine33.81%
   Diethylene Glycol dinitrate30.22%
   Graphite0.14%
   Potassium Sulphate1.36%
Propellant bagViscose rayon
Cartridge caseBrass coated, 1010 type steel
Thickness of brass coating0.0001 in.
Base insertPhenol-formaldehyde resin

German: p. 313

Categories
German

Method of Ramming and Indexing Splined Projectile

Method of Ramming and Indexing Splined Projectile

Indexing and ramming the 28 cm prerifled projectile in the German railway gun, 28 cm K5 (E), is accomplished with the aid of the rammer which, by gripping the base of the shell, allows the projectile to be indexed during its final travel through the powder chamber. Fitted centrally in the flat head of the rammer are two claws, reversed to each other and held outwardly by spring tension. A circular undercut recess in the base of the projectile receives these two claws holding the base of the shell against the face of the rammer. Two keyways milled in the periphery of the base of the shell receive corresponding, lugs on the face of the rammer and hold the members in rotation. Four evenly spaced lugs projecting longitudinally from the face of the rammer fit over the sides of the base of the projectile and hold the two in a transverse direction.

The head is fitted by a universal joint to the rammer, the front portion of which is a plain two-inch shaft approximately ten feet long and the rear portion machined with four longitudinal splines set at the same angle as the rifling of the tube. Over the splined portion of the rammer, which is 6 feet, 10/4 inches long, slides a collar fitted with two radially projecting horns set at approximately 75 degrees. The last 16 1/4 inches of the rammer are not splined and the extremity threaded, in all probability to receive a transverse handle. A lever which depresses the claws to release the head from the base of the projectile is fitted to the rear portion of the shaft.

A bracket bolted in the rear face of the breech ring has the function of receiving in two longitudinal keyways, the extremities of the two radial horns of the sliding collar.

In operation, the rammer is held securely to the base of the projectile and the shell is rammed through the powder chamber until the two horns of the sliding collar, in its forward position along the splines, engage in the two matching keyways of the bracket fitted to the rear of the breech ring. At this point, the shell, which still has approximately 2 feet, 6 3/4 inches to travel before the leading edge of the splines engage in the grooves of the rifling, is indexed and during the remaining forward travel of ramming remains indexed by virtue of the sliding collar which being held against rotation causes the rammer sliding through it to rotate at the same twist as the rifling.

The position of the two horns can be adjusted in relation to the body of the collar and once set for a particular gun, no further adjustments are necessary. A scale etched on the spline portion of the rammer indicates the depth of ramming from 2,850 to 4,050 centimeters for the 28 cm K5 (E).

German: p. 312.2 (June 1, 1945)

Categories
German

28 cm R. Gr. 4331: Rocket Assisted Prerifled Projectile

28 cm R. Gr. 4331: Rocket Assisted Prerifled Projectile

This high explosive projectile is fired from the 28 cm K. 5 (E) railway gun, and is prerifled in the same manner as the 28 cm Gr. 35 described on page 312. The outstanding feature of this new projectile is an increase in range from 67,800 yards to 93,100 yards—nearly 53 miles. This increase of 37% over the maximum range for the standard high explosive round is the result of energy supplied to the projectile by the addition of rocket propellant powder which is ignited 19 seconds after leaving the gun. After building up sufficient pressure to shear the lip on the base plug, the rocket propellant located in the ogive of the projectile discharges through a central venturi tube.

On the main body there are 12 steel splines set at the angle of rifling. The forward body (ogive) is threaded externally to screw into the main body and internally at its nose to receive the fuze and a rocket propellant ignition system. The venturi tube which extends from the base of the projectile to its middle section is secured by being screwed into the fuze and venturi adapter. A spun glass sleeve insulates the venturi tube from the explosive charge which is cast on the resulting assembly. A Zt. Z. S/30 time fuze set to operate 19 seconds after the projectile is fired is screwed into the nose of the projectile. Two percussion fuzes, AZ 4331, are located in the venturi adapter. These are armed by the burning of the rocket propelling charge through a powder pellet incorporated in the fuze. The rocket propellant is moulded as one piece, and extending through it are eight longitudinal holes 3/4-inch in diameter, located around a circular hole 1 5/8-inch in diameter.

SPECIFICATIONS

Length of projectile (less fuze)       48.79 ins.
Diameter of ribs 11.70 ins.
Diameter of rotating band 11.85 ins.
Diameter of body 11.10 ins.
Total weight 545 3/4 lbs.
Rocket propellant weight 43 lbs.
Explosive weight 30 3/4 lbs.
Maximum range 93,100 yds.

German: p. 312.1 (June 1, 1945)

Categories
German

28 cm Rifled Projectile

German 28 cm Rifled Projectile

This pre-engraved projectile recovered in Italy is used for long range bombardment. It has longitudinal inclined steel splines and a single one-inch-wide copper band that acts as a gas seal. The splines are set at a slight angle to the axis of the projectile and are 19.2 inches in length. In loading the projectile, the splines are lined up with the rifling of the gun tube. The shell is 33 inches in length, exclusive of the windshield. Fragments indicate that the windshield would add an extra two feet to the length.

A nose percussion fuze (AZ 35 K) and a base fuze (BD Z 35K) are fitted. The Germans are reputed to have four types of 28 cm railway guns able to employ this type of projectile. They are: 28 cm Br. N. Kan E.; 28 cm K. 5 (E); 28 cm K. 5/1 (E); and 28 cm K. 5/2 (E).

SPECIFICATIONS

Caliber         280 mm (11.023 ins.)
Weight (approx.) 550 lbs.
Length (excluding windshield) 33 ins.
German: p. 312

Categories
German

10.5 cm HL, HL/A, HL/B, HL/C: Hollow Charge Ammunition

10.5 cm HL, HL/A, HL/B, HL/C: Hollow Charge Ammunition

There are four known variations of the 10.5 cm (105 mm) hollow charge ammunition fired from the German 10.5 cm le. F. H. 18 series:

Type Hl has a deep conical cavity, a short ogive, and flash tube extending through the shaped cavity to the fuze booster. All types have an additional detonator booster combination at the base of the flash tube.

Type Hl/A has the same shaped cavity but has a larger diameter flash tube that is attached to the apex of cavity liner by a pressed collar, and does not extend into the cavity. This type has a long ogive.

The principal difference between types Hl/A and Hl/B is in a shallower, hemispherical-shaped cavity. The principal difference between types Hl/B and Hl/C is the addition of a funnel-like steel washer inverted over the cavity. This funnel is supposed to counteract the effects of centrifugal force on the hollow charge jet.

The explosive filler is pressed into two pellets in types Hl/A, Hl/B, and type Hl/C. Explosive fillers in all rounds are inclosed in waxed paper cartons. The metal ogive screws into the projectile, holding all components of the filler in place.

The aluminum fuze (AZ 38) carries the primer detonator. It is armed by centrifugal force and contains no other safety features. It functions by a “spit” from the booster, which travels down the central tube and initiates the base booster, and hence the main bursting charge.

ESSENTIAL MODIFICATIONS

Type Hl/A: (a) Lengthened nose-piece (ogive), giving greater standoff. (b) Elimination of flash tube between fuze and apex of cavity and larger diameter of flash tube.

Type Hl/B: (a) Further increase of standoff obtained by shortening the HE filler. Nose piece is identical with that of Type Hl/A. (b) Hemispherical cavity instead of rounded cone. (c) HE filling RDX/WAX, instead of RDX/WAX/TNT.

Type Hl/C: Introduction of a washer, shaped like an inverted funnel in front of the cavity. Otherwise, types B and C are essentially identical.

SPECIFICATIONS

        Hl       Hl/A       Hl/B       Hl/C
Weight of projectile as fired:25.8 lb.27.1 lb.26.6 lb.27.2 lb.
H.E. filling, carton, wax: 4.6875 lb.3.5 lb.3.255 lb.
Empty shell: 22.55 lb.22.937 lb.22.315 lb.
Collar (“funnel”)   .5195 lb.
Muzzle velocity f/s*1375136013601360

Estimated performance at normal against Homogeneous armor.
     Type Hl/A—170 mm (static) 105 mm (dynamic)
     Type Hl/B—155 mm (static) 100 mm (dynamic)
     Type Hl/C—155 mm (static) 100 mm (dynamic)
                       (From German claims)

*Firing with charge five which is normally used.

German: p. 310 (August 1, 1945)

Categories
German

8 cm Wurfgranate 39: 8 cm Mortar Shell “Bouncing Betty”

8 cm Wurfgranate 39: 8 cm Mortar Shell - Bouncing Betty

The 8 cm Wgr. 39 consists of a nose fuze, front cap, rear body, and tail assembly. The body, which is separated from the cap at the ogive, has a standard shape and TNT filling. The cast nose cap fits over a cylindrical boss, concentric with the longitudinal axis of the projectile. This cap is secured to the boss by four shear pins that extend through the cap and the boss. The seam where the two parts are joined is then shellacked to form a watertight seal.

An impact type, nondelay fuze is screwed into the cap; inside the cap is a plastic container of about 1 1/2 ounces of smokeless powder. Under the charge, screwed into the projectile body, is an iron plug with a small axial hole through it. This plug separates the smokeless powder charge from the combination delay pellet and booster which is in an aluminum container.

The tail assembly is a standard type, having the usual base charge, ring increments, and fin assembly.

Upon impact, the nondelay fuze ignites the smokeless powder charge, sending a flash through the hole in the separating plug, setting off the delay pellet. The explosion from the first charge shears the pins holding the nose cap to the projectile body, and throws the shell from 5 to 10 feet into the air. In the meantime, the booster detonates the main TNT bursting charge at approximately the moment when the projectile is at the height of its bounce. This gives the effect of an air burst without the use of a precision time fuze. Height of the burst is governed by the angle of the shell axis with the ground at the time of impact.

KEY TO PARTS:
     (A) Propellant increments
     (B) Propellant cartridge
     (C) Projectile body
     (D) False ogive
     (E) Point ignition fuze—Wgr. Z 38 st
     (F) Booster well
     (G) Booster capsule
     (H) Delay type detonator
     (I) Paper washer
     (J) Paper diaphragm
     (K) Plastic washer
     (L) Booster well adapter
     (M) Ejector capsule
     (N) Ejector capsule igniter

German: p. 309 (August 1, 1945)

Categories
German

7.5/5.5 cm Pzgr. Patr. 41 (W): 7.5 cm Pak 41 Armor-Piercing Ammunition

7.5/5.5 cm Pzgr. Patr. 41 (W): 7.5 cm Pak 41 Armor-Piercing Ammunition

This round is designed for use in the 7.5/5.5 cm Pak 41 tapered bore antitank gun described on page 123 of this volume. It is an armor piercing tracer projectile of Gerlich design with the nomenclature 7.5 cm Pzgr. Patr. 41 (w).

The projectile consists of an outer case, a tungsten carbide core 1.16 inch in diameter, a screw head, a ballistic cap, and a tracer. It is fired from a regular cartridge consisting of cartridge case 6344, primer C/12n. A. St., an igniter of pyroxylin porous powder, and the propelling charge of diglycol tubular powder.

SPECIFICATIONS

Total weight of round        16.65 lb.
Total length of round        29.8 ins.
Weight of projectile        5.68 lb.
Weight of tungsten carbide core        2.01 lb.
Diameter of core        1.16 ins.
Weight of propellant charge        5.4 lb.

German: p. 306.2

Categories
German

15 cm Stielgranate: 15 cm Stick Grenade

15 cm Stielgranate: 15 cm Stick Grenade

The German 15 cm high explosive Stick Grenade is reported to be used with the 15 cm heavy infantry gun, s. I. G. 33. Its prime purpose is for demolition, and for clearing minefields and wire obstacles. Of welded steel construction, the bomb has a 1/8-inch case consisting of three main parts: the nose, a cylindrical center piece, and a tapered rear piece. Both the nose and the base are reinforced with steel rings welded to the casing. The ring in the nose is tapped to receive the fuze adaptor; that in the base to accommodate a steel cup. This cup, which has machined surfaces, is 3/8-inch thick at the base and 3/16-inch at the sides. A stick unit which leaves the bomb approximately 150 yards from the muzzle of the gun fits over the cup. According to reports, the unit weighs 22.2 kg. (49 lb.) and the propelling charge 5.5 (12 1/8 lb.).

The main filling consists of approximately 60 pounds of poured 50/50 Amatol. A 2-inch cylindrical booster charge made up of compressed T.N.T. pellets is located in the center of the main filling about 15 inches from the booster; two normal annular picric pellets surround the booster. The bomb is fitted with a percussion type nose fuze, Wgr. Z. 36, which is also reported as being used in the German 20 cm Spigot Mortar Bomb. The tail, of unusual construction, has three tubular steel sockets equally spaced around the bomb and projecting from the rear portion of the casing at an angle of 20° to the main axis. These sockets receive tubular bars to which the sheet steel tubular fins are attached. The bars are bent in order to bring the fins parallel to the main axis and also to provide clearance of the muzzle of the gun. In addition there are six 5/32-inch steel plate fins welded to the casing and spaced in pairs between the tubular sockets.

SPECIFICATIONS

Overall length        50 1/2 ins.
Overall length (excluding tail fins & fuze) 30 3/4 ins.
Diameter (maximum) 11 1/2 ins.
Thickness of casing 1/8 in.
Total weight (approx.) 105 lb.
Weight of filling (approx.) 60 lb.
Color Field grey

German: p. 306.1

Categories
German

Topf Mine: Antitank Mine

Topf Mine: Antitank Mine

The Topf Mine, a completely non-metallic, waterproof, antitank mine, consists of a circular body filled with a 12 1/2-pound charge of TNT, a primer plug assembly, and an igniter. The top of the mine is flat, with a fixed pressure plate in the center slightly higher than the surface; a 4 1/2-inch circular recess located in the bottom takes the primer plug and igniter assembly. The outer casing is made of a hard pulp-like material covered with pitch. The mine rests on three glass studs; two of the studs secure a pasteboard carrying handle, while the third, which is sometimes larger than the two others, is used as a filler plug.

The primer plug assembly consists of a glass screw cap and a cylindrical wooden booster holder, the top of which has a deep threaded recess to take the Topf Mine Igniter. A subsidiary igniter socket in the glass cap leads to the booster charge, and is threaded to take a standard igniter.

The Topf Mine Igniter, which is made of glass, has no safety device. It comprises a cylindrical glass body 3 mm thick; a solid glass pressure head, hemispherical in shape and two small glass ampules, one of which contains sodium and potassium as a liquid alloy and the other ethyl nitrate. The ampules are held in position by a black celluloid disc. A thin bakelite detonator well is provided.

The mine is activated by a pressure of at least 330 pounds, which forces the pressure plate down onto the igniter head and thereby breaking the two glass ampules. A flash results, setting off the detonator, booster, and main charge. If a standard igniter is used, the mine must be laid upside down.

SPECIFICATIONS

Diameter of mine        12 1/2 ins.
Height of mine 5 1/2 ins.
Weight (complete) 20 lbs.
Weight in crate 29 lbs.
Filling TNT
Weight of filling 12 1/2 lbs.
Firing pressure 330 lbs.
Height of igniter (including cap) 3 1/2 ins.
Diameter of igniter body 1 1/2 ins.
Shear pressure of igniter 132 lbs.
Overall height of primer plug assembly 3.1 ins.
Diameter of primer holder 2 1/2 ins.
Diameter of glass cap 4.6 ins.

German: p. 304.9 (May 1, 1945)