Langer Max

38 cm SK L/45 "Max"
"Max" mounted on its combined railroad and firing platform
Type	Naval gun Railroad gun
Place of origin	German Empire
Service history
In service	1915–18
Used by	German Empire
Wars	World War I
Production history
Designer	Krupp
Designed	1912–14
Manufacturer	Krupp
Produced	1914–18
No. built	8
Variants	B, E, E.u.B.
Specifications
Weight	267.9 tonnes (263.7 long tons; 295.3 short tons)
Length	31.61 metres (103 ft 8 in)
Barrel length	16.13 metres (52 ft 11 in) L/42
Shell	separate-loading, case charge
Calibre	38 centimetres (15 in)
Breech	horizontal sliding-block
Recoil	hydro-pneumatic
Carriage	2 x 5-axle and 2 x 4-axle bogies
Elevation	+0° to +18.5° (+55° if emplaced)
Traverse	2° (up to 360° if emplaced)
Muzzle velocity	800 to 1,040 m/s (2,600 to 3,400 ft/s)
Effective firing range	22,200 metres (24,300 yd) (from rails)
Maximum firing range	47,500 metres (51,900 yd) (if emplaced)

The 38 cm SK L/45 "Max", also called Langer Max (literal translation "Long Max") was a German long-range, heavy siege and coast-defense gun used during World War I. Originally a naval gun, it was adapted for land service when it became clear that the ships for which it was intended would be delayed and that it would be very useful on the Western Front.

The first guns saw service in fixed positions, (for example at Verdun in February 1915,) but the lengthy preparation time required for the concrete emplacements was a severe drawback and a railroad mount was designed to increase the gun's mobility. The latter variants participated in the 1918 Spring Offensives and the Second Battle of the Marne.

One gun was captured in Koekelare (16 October 1918) by the Belgians at the end of the war and the seven surviving cannons were destroyed in 1921 and 1922.

They were originally designed as the main armament of the Bayern-class battleships, but were deployed in fixed (Anschiessgerüst) and semi-portable (Bettungsgerüst) concrete emplacements that took weeks to months to build. One obvious change made for land service was the placement of a large folding counterweight just forward of the trunnions to counteract the preponderance of weight towards the breech. This, although heavy, was simpler than adding equilibrators to perform the same function. It folded to lower the gun's height while travelling.

To meet the demands for more mobility and a faster emplacement time, Krupp designed a combination railroad and firing platform mounting (Eisenbahn und Bettungsgerüst - E. u. B.) at the end of 1917 using guns released by the hulking of SMS Sachsen and SMS Württemberg. This mount allowed the gun to fire both from any suitable section of track and from a fixed emplacement. The E. u. B. mount used a combination of cradle and rolling recoil systems to absorb the recoil forces when firing from rails. It could traverse a total of 2° for fine aiming adjustments, coarser adjustments had to be made by moving the entire carriage. The gun had to be loaded at zero elevation and so had to be re-aimed for every shot. One major problem when firing from rails was that the lengthy recoil movement of the gun prevented elevation past 18° 30' lest the breech hit the ground when firing, which limited range to 22.2 kilometres (24,300 yd). Nicknamed Max, the gun's (supporting) barrel and railway-transportable carriage was used in the famed Paris Gun. Some guns were also emplaced in the Pommern and Deutschland coastal defense batteries on the Flanders coast protecting occupied Ostend.