French 47mm cartridges for the SA35 L/32 tank gun

[pzgr40]

Cutaway models of two French 47mm cartridges for the SA35 L/32 tank gun. Left, the ‘Obus Explosive 47mm Model 1932’, German nomenclature 4,7 Cm Sprgr. Patr. 32B (f), right the ‘Cartouche a Boulet Perforant Mle35’, German nomenclature ; 4,7cm Pzgr. Patr 35 (f).

These cartridges were used in 47mm SA35 L32 gun of the Char B1-Bis, Char S35, Somua S35 tanks, which were taken into service in the 30’s of the last century and were used throughout the war by Germany as spoils of war. Although these tanks were state of the art at the beginning of WW2, they were obsolete at the end of WW2.

The -high explosive - ‘Obus Explosive 47mm Model 1932’ consists of a mild steel body with the nose fuze ‘Fusee detonateur percutante a verrous type Gaba model 1932’ screwed in top.
The shellcase is filled with two bundles of tape powder ; the main charge consists 130 grams of BC or BCP tape powder strips 85 mm long, with a top bundle of 60 grams of BC or BCP tape powder cut to a length of 42 mm which is tied together as a bundle.

Description and functioning of the ‘Fusee detonateur percutante a verrous type Gaba model 1932’ ;
The fuze body (1) is steel made, with a brass screw (2) in top which houses the fixed firing pin at the base. At the side of the fuze body three radial holes are drilled at 120 degrees each, in which a spring loaded brass cup (3) is placed. These cups fixate the safety collar (4, green) in the lower position before fired (transport safety). Inside the safety collar the inertia weight (5) is placed, housing the firing cap (red). A light spring is placed between the inertia weight and the safety collar, trying to push the safety collar (4) upward. The lower side of the inertia weight rests over a flange (6) which houses the flame booster (black). The hole in this flange and the lower part of the hole of the inertia weight (5) are threaded to receive a spring (7) that pulls both parts together. This spring acts as a resistance to prevent the fuze from functioning on -too- light impact. The detonator (8) is screwed into the base of the fuze body.
Upon firing the inertia weight (5) and the safety collar (4) are forced in the aft position, and the centrifugal force swings the three brass cups (3) outward, releasing the safety collar (4). When the accaleration decreases, the spring between the inertia weight and the safety collar pushes the safety collar forward, arming the fuze. Upon impact the inertia weight is swung forward, stretching the spring (7) in it’s hole, pushing the firing cap into the fixed firing pin. The flame of the firing cap travels down the hole into the flame booster which ignites the mercury fulminate filled detonator (8), which detonates the main charge in the projectile.

Cartridge length : 341 mm
Shellcase length : 193,5 mm
Projectile length with fuze : 183 mm
Weight projectile : 1,41 Kg
Explosive charge : 0,142 Kg cast Melenit- dinitronaphatalin
V0: mtrs/sec

The -armour piercing- ‘Cartouche a Boulet Perforant Mle35’ consists of a machined and nose hardened steel body to which a steel piercing cap is roll crimped in place.
The shellcase is filled with two bundles of tape powder ; the main charge consists 245 grams of BC or BCP tape powder strips 135 mm long, with a top bundle of 45 grams of BC or BCP tape powder cut to a length of 70mm which is tied together as a bundle. A red linnen bag containing tin foil is placed on top of the powdercharge and acts as a decoppering agent for the barrel.

Cartridge length : 325 mm
Shellcase length : 193, 5 mm
Projectile length : 145 mm
Weight projectile : 1,63 Kg
V0: 670 mtrs/sec
Penetration of steel plate @ 0 degrees ; 69mm at 100 mtrs, 63 mm at 200 mtrs, 56mm at 400 mtrs, 46mm at 800 mtrs, 38mm at 1200 mtrs.
Penetration of steel plate @30 degrees ; 59mm at 100 mtrs, 54 mm at 200 mtrs, 48mm at 400 mtrs, 39mm at 800 mtrs, 32mm at 1200 mtrs.

Regards, DJH