Extended Magazines

"USSR NKO

Commander of Armoured and Mechanized Forces of the Red ARmy

July 19th, 1944

#511127

Trials were held to establish the possibility of increasing the amount of ammunition carried in SPGs, which increases the ammunition capacity of the ISU-152 and ISU-122 by 7 rounds and the SU-85 by 5 rounds if necessary.

Additional ammunition is to be carried in the following ways:

1. In the ISU-152: 4 armour piercing shells on the floor of the fighting compartment in the rear, along the engine compartment bulkhead, tip pointed to the rear. One shell above them, pointing to the left. 4 propellant casings on the bottom of the fighting compartment underneeath the gun breech (instead of the currently installed toolboxes) and one underneath the loader's seat.
2. In the ISU-122: 5 shells on the floor of the fighting compartment under the loader's feet (instead of the toolbox) pointing forward. 3 propellant casings on the floor in the rear near the engine compartment bulkhead behind the additional ammunition, one on the right side under the loader's seat, one on the floor under the loader's seat.
3. In the SU-85: 5 rounds on the floor of the fighting compartment under the brass catcher pointing forward, one on the left side under the loader's seat pointing forward. 

When additional ammunition is carried, move the toolboxes from the floor of the fighting compartment to bulge in the right side of the ISU-152 fighting compartment and the right and left sides of the ISU-122 fighting compartment.

Additional ammunition carried in all SPGs must be kept in wooden frames and kept in place with straps.

The additional ammunition confines the movement of the loader and so must be expended first.

Teach personnel in schools and active units how to install additional ammunition racks, paying special attention to how to preserve them. Failure to adhere to safety procedures can result in damage to fuses, denting of casings, jamming of shells, weakening of 85 mm round crimping, and to accidents.

Deputy Commander of the Armoured and Mechanized Forces of the Red Army, Lieutenant General of the Technical Forces, Volskiy"

Via ivagkin.