53 mm Gruson cartridges

[pzgr40]

The 53mm Gruson gun was designed in 1890 by the Gruson company in Magdeburg, and was knowns as the '5cm Schnellfeuer kanone'. It used fixed ammunition and had an impressive firing rate of 25 rounds per minute. When mounted on a two wheeled casemate carriage it could be rolled in and out position in a fortress, and this gun became known as the '5cm Schnellfeuer kanone in Kazematt Lafette. Later on the gun was placed in a small steel cupola in fortresses, allowing it to be rolled in and out of position over a rail. This allowed the gun to be rolled in shelter under enemy shelling, and rolled back into position before the enemy attack.
The most famous version of the fun was the Fahrpanzer, when the cupola was placed on a carriage, at first horse drawn, later on a truck, which became known as the 'Fahrpanzer'. In fact the first auxiliary artillery to be used on the front.
The Romanian army used an infantry version the 5,3 cm Gruson gun on a 'normal' horse drawn gun carriage, known as the 'Tunul Gruson calibrul 53mm , model 1887/1916'.

Left, the ‘5cm Granatpatrone’. The projectile consists of a cast iron body, filled with black powder. The top of the projectile is internally threaded to receive the 5cm Gr.Z (Granaten zunder). This is a concussion impact fuze. Before firing, the firing pin (1) is held in backward position by a set-back ring (2) , which is held in upper position by a stirrup spring ring (3) with four lips. Upon firing, the set-back ring (2) moves backward, bending the four lips of the stirrup spring ring (3) inwards. The firing pin is now free to move forward. Upon impact, the firing pin will move into the firing cap (4), which ignites the main charge of black powder in the projectile body.

Right, the Shrapnelgranate. The projectile body is steel made with a reduction in diameter in the lower inner portion of the projectile body which supports a steel flange with a flame pipe in the center. The portion below the flange is filled with 27 grams of black powder (expulsion charge), the portion above the flange is filled with 56 hard lead balls. The standard fuze used is the 53 mm Doppel zunder Model 1891.
Function of the Doppelzunder Model 1891;
Before firing, the time fuze is set to the required time by rotating the timing ring (1) of the pyrotechnic fuze. The lower angled flame channel (2) to the flame pipe (3) -leading to the expulsion charge- is closed by the set-back ring (4) of the impact fuze (5). Upon firing, the set-back weight (6) with the firing cap (7) moves backward into the firing pin (8), as well as the set-back ring (4) of the impact fuze which is now armed. The flame of the firing (7) cap travels through one of six drilled flame channels (9) into the pyrotechnic fuse ring (10) which starts burning until it reaches the lower angled flame channel (2). The flame travels into the expulsion charge in the base of the projectile which projects the flange forward until the thread of the fuze is ripped off, projecting the 56 lead balls forward. The rotation of the projectile body enshures the balls spread in a cone shaped pattern.
If the time fuze is not set, either fails, the impact fuze will function upon impact; inertia throws the firing pin (11) of the impact fuze forward into the lower firing cap (12), igniting the expulsion charge.

The brass shellcase is 176 mm long and has a small powder charge of rifle powder, kept in the lower position by means of a felt disc disc, which is kept in the lower position by a cardboard cross, placed between the base of the projectile and the felt disc. A striking detail is that the projectile is placed not with the driving band on the shellcase mouth, but 10 mm higher.

Regards, DJH.