Tag Archive for 'projectile'

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)

38 cm R. Sprgr. 4581: Rocket Projectile for Raketenwerfer 61

38 cm R. Sprgr. 4581: Rocket Projectile for Raketenwerfer 61

This projectile is fired from the Raketenwerfer 61 (see pages 38.3 and 38.4). It shows a radical departure from standard spin-stabilized rocket design by the use of insert splines at the after end of the motor body. These splines, fitting into the rifling of the projector liner, aid in giving an initial spin to the projectile.

The rocket consists of three main assemblies: the high explosive body, motor body, and nozzle assembly.

The high explosive body of two-piece welded construction is threaded internally at its after end to receive the motor body. The booster pocket and fuze adapter assembly is welded in position at the nose of the high explosive body. The bourrelet is located just behind the welded junction of the ogive and the cylindrical section.

The motor body is threaded externally to screw into the high explosive body and internally to receive the nozzle assembly. Both the explosive body and nozzle assembly are secured by means of two diametrically opposed set screws. Nine grooves for the splines are machined into the base of the periphery of the motor body. The high explosive body is filled with 270 pounds of the German explosive charge 13A, which is 50/50 poured amatol.

The 32 venturi holes in the nozzle plate are set at an angle of 14° to the axis of the rocket. In the center of the nozzle plate there is a threaded hole to receive the igniter primer for the rocket propellant.

A rear spacer ring welded to the nozzle plate aids in the positioning of the outer row of propellant charges.


Caliber         38 cm (15 ins. approx.)
Total weight of rocket 761 lbs.
Overall length (not including fuze) 56.68 ins.
Diameter of bourrelet 14.94 ins.
Maximum range 6,179 yds.
Weight of explosive charge 270 lbs.
Weight of propellant charge 88.5 lbs.
Fuze Point detonating
Weapon from which fired Raketenwerfer 61

German: p. 354.2 (June 1, 1945)