The 15 cm sIG 33 (schweres Infanteriegeschütz 33, or “Heavy Infantry Gun 33”) was the standard heavy infantry gun of the German Army throughout the Second World War.
Designed by Rheinmetall in the early 1930s, it provided close, high-explosive fire support to frontline infantry units, capable of destroying fortified positions, bunkers, and enemy troop concentrations with devastating accuracy.
Chambered for a 149.1 mm (5.9 inch) shell and mounted on a conventional split-trail carriage, the sIG 33 could fire a 38 kg (84 lb) high-explosive round to a maximum range of 4.7 km (2.9 miles).
Despite its relatively short range, its heavy shell and steep trajectory made it ideal for urban and defensive combat, especially in support of assault troops.
Weighing over 1,800 kg (4,000 lbs), the gun was cumbersome to move by hand and often required towing by half-tracks or field tractors.
To improve mobility and battlefield survivability, it was later adapted onto several self-propelled mounts — most notably the Sturmpanzer I Bison, Grille, and Sturmpanzer 38(t) — combining heavy firepower with tracked mobility.
Used extensively from Poland in 1939 through to the final battles of 1945, the 15 cm sIG 33 earned a reputation for reliability and destructive power.
Its massive shells could level buildings and strongpoints, making it one of the most feared support weapons in the German arsenal.
The sIG 33 stands today as a classic example of German heavy artillery design — simple, robust, and brutally effective on the battlefield.
