Staff Writer (Updated: 7/11/2014):
The leFH 18/40 was initially designed to bring about a revised form of the available existing German 105mm field guns. Specifically, the Wehrmacht issued a requirement for a lighter field weapon so as to make them readily portable. Additionally, as Germany was embroiled in all-out war on multiple fronts by this time, the new weapon would also have to be easier to produce at German factories. Therefore, the new weapon would consist of components from several proven and existing systems.
The gun barrel assembly of the leFH 18M was selected as the primary armament and the carriage of the 7.5-cm (75mm) PaK 40 anti-tank gun was selected as the standard mount. The gun featured a double-baffled muzzle brake to help contend with recoil. The PaK 40 carriage was slightly modified for the new design and revised to include torsion bar suspension and a pair of pressed-steel, rubber-tired spoked wheels. The end-product came under the German Army designation of 10.5-cm leFH 18/40 (10.5cm indicating the gun's caliber and leFH indicating "leiche Feldhaubitze" in the German).
The leFH 18/40 followed the conventional form of contemporary field guns. The barrel was set onto a gun mount that was further attached to a two-wheeled trailer system with split trail legs that doubled as both a recoil mechanism (when firing) and a tow leg (when in transport). The crew was meagerly protected along the front facing by a contoured armored shield. All major working components (elevation/firing controls) were housed in the rear area of the gun near the breech. The breech was of a manually-actuated horizontal sliding block, each shell loaded with applicable charge. The weapon was fired via a percussion system and lever along the left side of the gun mount. The gun measured in at 105mm (4.13 inches) and the recoil was of a hydopneumatic response. Elevation spanned from -6 to +40 degrees with traverse within the gun mount limited to 56-degrees. Of course the crew could swing the entire weapon towards a target area manually to achieve a full 360-degree traverse possibility. A trained crew could let-off between six and eight rounds per minute. Laying was managed by a standard German Army artillery field sight device. Muzzle velocity was rated at 1,772 feet per second. Effective range was out to 13,479 yards. A standard operating crew was between four and six personnel. Operational weight of the leFH 18/40 was 4,311lbs (1,955kg). The system measured in at 9.64 feet in length and the barrel was 9 feet of this measurement. The leFH 18/40 could be towed by various German Army vehicles that were properly equipped to transport like-artillery systems.
Ammunition types available to the gunnery crew ran the standard gamut of High-Explosive (HE), High-Explosive Incendiary (HEI), standard smoke projectile, night illumination "star" shell, propaganda leaflet shell, hollow charge and marking shell.
While some were available in limited quantities by the end of 1942, the system did not witness wide-spread use - and subsequent combat actions - until after February of 1943. Once in full service by 1944, the leFH 18/40 system was fielded with artillery battalions of the German Army and proved a reliable addition to the inventory, matching the ballistic capabilities of the original leFH 18(M) series while proving to be lighter. They would continue to see use until the final days of the war in Europe in May of 1945.