22.5 cm Minenwerfer M 15

The 22.5 cm Minenwerfer M 15 was a heavy mortar used by Austria-Hungary in World War I. It was developed by Böhler as an alternative to the German Ehrhardt 25 cm schwere Minenwerfer which Böhler was having problems building under license. It was a muzzle-loading, smooth-bore mortar that had no recoil system whatsoever. The entire mortar had to be levered around to aim at new targets. It was not particularly accurate and bombs often fell over in flight and landed on their sides so they used time instead of contact fuzes. It fired high-explosive and gas shells. For transport two wheels from the Gebirgsgechütz M 99 were used.

22.5 cm Minenwerfer M 15
22.5 cm Minenwerfer in 1917
Type	Heavy trench mortar
Place of origin	Austria-Hungary
Service history
In service	1915-1918
Used by	Austria-Hungary Ottoman Empire
Wars	World War I
Production history
Designer	Böhler
Designed	1914-15
Manufacturer	Böhler
Produced	1915-18
No. built	930+
Variants	M 16 and M 17
Specifications
Mass	565 kg (1,246 lb)
Length	1.35 m (4 ft 5 in) L/6
Shell	48 kg (106 lb)
Caliber	225 mm (8.9 in)
Elevation	+25° to +75°
Traverse	0°
Rate of fire	2 rpm
Muzzle velocity	170 m/s (560 ft/s)
Maximum firing range	675 m (738 yd)

The M 17 version of this weapon had an elevation screw with a double thread and reinforced trunnion bearings. It's unclear how the M 16 differed from the earlier model.