Just one month prior to the commencement of "Operation Typhoon" (the German assault on Moscow) the Waffenamt was scheduled to begin installing the long-barreled 7.5cm KwK gun on its new Mark IV Ausf G tanks. However, when the Wehrmacht encountered the superior Russian KV-1 and T-34 tanks during the summer campaigning season, a decision was made to mount the 7.5cm KwK40 L/43 gun onto as many existing Mark IVs as possible. Since the new gun fired larger rounds than the short-barreled gun mounted on the F1 tanks, ammunition storage capacity had to be increased and the crew compartment had to be re-arranged to accomodate the modifications.

Produced from 1944-'45, the Ausf. J, of which 1758 vehicles were produced, was reconfigured so the turret traverse engine was replaced with an extra fuel tank. Later Ausf. Js had simplified vertical exhaust mufflers and the use of 3 instead of 4 track return rollers. Very late Ausf. J's used wire mesh side-skirts ( Drahtgeflecht Schürzen) in place of solid metal plates to conserve strategic materials and reduce overall weight.

Pictured here is a 1:72 scale replica of a German Sd. Kfz. 161 PzKpfw IV Ausf. J medium tank with schurzen side armor skirts that saw action in Germany during 1944. Comes in D-Day Commemorative packaging. Sold Out!

Dimensions:
Length: 4-inches
Width: 1-1/2-inches

Release Date: August 2009

Historical Account: "Schurzen" - During World War II, shaped-charge liners were made of copper or steel, though other materials were tried or researched. The precision of the charge's construction and its detonation mode were both inferior to modern warheads. This lower precision caused the jet to curve and to break up at an earlier time and hence at a shorter distance. The resulting dispersion decreased the penetration depth for a given cone diameter and also shortened the optimum standoff distance. Since the charges were less effective at larger standoffs, side and turret skirts (known as Schürzen) fitted to some German tanks to protect against Russian anti-tank rifle fire were fortuitously found to give the jet room to disperse and hence reduce its penetrating ability.

The use of skirts today may increase the penetration of some warheads. Due to constraints in the length of the projectile/missile, the built in stand-off on many warheads is not the optimum distance. The skirting effectively increases the distance between the armour and the target, providing the warhead with a more optimum standoff and greater penetration if the optimum stand-off is not drastically exceeded. Skirting should not be confused with bar/slat/chain armour which is used to damage the fuzing system of RPG-7 projectiles. The armour works by deforming the inner and outer ogives and shorting the firing circuit between the rocket's piezoelectric nose probe and rear fuze assembly. If the nose probe strikes the armour, the warhead will function as normal.

The spacing between the shaped charge and its target is critical, as there is an optimum standoff distance to achieve the deepest penetration. At short standoffs, the jet does not have room to stretch out, and at long standoffs, it eventually breaks into particles, which then tend to drift off the line of axis and to tumble, so that the successive particles tend to widen rather than deepen the hole. At very long standoffs, velocity is lost to air drag, degrading penetration further.