10.5 cm 31.M field gun

The 10.5 cm 31.M ágyú or Bofors 105 mm cannon model 1931 was a heavy field gun designed by Sweden and produced/used by Hungary on the Eastern Front in World War II.

10.5 cm 31.M field gun
Type	Heavy field gun
Place of origin	Sweden/Hungary
Service history
Used by	Kingdom of Hungary
Wars	World War II
Production history
Designer	Bofors (Sweden)
Designed	1927-1931
Manufacturer	MÁVAG (Hungary)
Developed from	10.5 cm cannon Model 1927
Specifications
Mass	5,100 kg (11,243.58 lb) (in firing position) 5,995 kg (13,216.71 lb) (in travel position)
Barrel length	5,250 mm (17.22 ft) L/50
Crew	9 [a]
Shell	105×567mmR [b]
Shell weight	17.5 kg (38.58 lb)
Caliber	105 mm (4.13 in)
Breech	Interrupted screw
Recoil	Hydropneumatic [c]
Carriage	Split trail
Elevation	-5° / +45°
Traverse	45°
Rate of fire	6–8 rounds/min [d]
Muzzle velocity	825 m/s (2,710 ft/s)
Maximum firing range	19.5 km (21,300 yd)

History

In the late 1920s, Swedish Bofors with assistance from German company Krupp developed several 105 mm field guns that can mainly be divided into two types - a 4-ton class and a 5-ton class. The M1927 and M1934 (an improved version of the M1927) ​​were in the 4 ton class, while the M1931 was in the 5 ton class. These guns shared a carriage with the similar 15 cm M1931 howitzer, which Hungary also used. This was done to standardise parts, simplifying production and lowering costs. In 1931, Hungary bought the licence for the M1931 gun and commissioned MÁVAG to produce it as the 10.5 cm 31.M field gun.^[1]

The 10.5 cm 31.M field gun differed from the original M27 and M34 guns in many specifications; it was heavier, had a longer barrel, higher muzzle velocity, more range, and fired a heavier shell, among other differences. The 31.Ms were mechanised artillery guns (towed by vehicles rather than horses) and were used by artillery units which supported infantry, mechanised infantry and tanks. Not many of these guns were manufactured and all were lost in the Ostrogozhsk–Rossosh Offensive in January 1943.^[2]

The 10.5 cm 31.M field gun and 15 cm 31.M howitzer were some of the most advanced and elite artillery in the Hungarian inventory during the war, and they were well-liked weapons that performed on par with modern artillery of other nations, however Hungary did not have enough modern artillery pieces and often had to supplement them with weaker, more outdated guns. The 10.5 cm 31.M field gun may have been the longest range artillery gun in the Hungarian inventory.^[3]