Krupp 75mm mountain gun M. 1886

Bulgarian designation :			75-мм нескорострелно планинско оръдие “Круп”
Krupp designation :			7,5cm Gebirgskanone L/13
Calibre :			75mm L/13
Weight of the barrel :			102 kg
Weight of the carriage :			157 kg (original carriage)
			244 kg (improved carriage adopted in 1892)
Weight in action :			259 kg with the original carriage
			346 kg with the improved carriage
Barrel length :			975 mm
Length of the bore :			845 mm
Length of the rifled part :			700 mm (9.4 calibres)
Barrel grooves		number :	24
		depth :	1.25 mm
		width :	7 mm
Length of twist :			1875 mm (25 calibres)
Height of the line of fire :			660 mm
Battering charge :			400 g of black powder (full charge) 150 g of black powder (reduced charge)
			165 g of smokeless powder (Würfel-Pulver C/89)
Common shell		weight :	4.3 kg - charge : 94 g of gunpowder
		max. range :	4000 m
Shrapnel C/88		weight :	4.355 kg – charge : 55 g of black powder 85 bullets x 15 g
		max. range :	2200 m
Shrapnel C/91		weight :	4.355 kg – charge : 55 g of black powder 170 bullets x 11 g
		max. range :	2200 m
Case shot :		weight :	4.2 kg
		max. range :	300 m
Muzzle velocity :			294 m/s with full charge 152 m/s with reduced charge
Remaining velocity :			228 m/s at 2200 m with shrapnel 195 m/s at 4000 m with common shell
Angle of elevation :			500 m – 1° 14’ 1000 m – 3° 05’ 1500 m – 5° 09’ 2000 m – 7° 31’ 3000 m – 13° 16’ 3500 m – 16° 55’ 4000 m – 21° 12’
Angle of descent :			at 100 m – 0° 24’ at 500 m – 2° 04’ at 1000 m – 4° 17’ at 1500 m – 6° 52’ at 2000 m – 9° 52’ at 2500 m – 13° 21’ at 3000 m – 17° 25’ at 3500 m – 22° 06’ at 4000 m – 27° 12’
Length of the line of sight  :			940 mm
Elevation :			+ 20° / - 10° (original carriage)
			+ 23° 12’ / - 6° (new carriage)
Wheels	weight :		55 kg
	track :		0.83 m
Transport :			4 loads: 1 – barrel (130 kg); 1 – trail; 1 – wheels and shafts; 1 – two ammunition boxes weighting 48 kg each
Ammunition :			in 1889 : 64 common shells, 40 shrapnel, 8 case shots in 1912 : 138 shells
Remarks : Slow firing steel mountain gun without mantel, equipped with a cylindro-prismatic wedge breech mechanism with the expanding steel obturation ring system Broadwell. It fired the same projectiles as the 75mm field gun M. 1886, but employed a lighter battering charge. At first the charge was composed by Feinkörniges Geschützpulver (black powder), but later the gun was modified to use the smokeless powder (Würfel-Pulver C/89). It was equipped with rope brake to reduce the recoil from 10-12 to 2-3 paces. Initially this gun was provided with a carriage that proved to be unable to withstand the force of the recoil to such degree that sometime it overturned. Therefore in 1892 it was removed and replaced with a stronger one. On short rides the old carriage could be towed by two horses without using a limber, by means of a shaft, which could be dismantled to be transported by pack horses.
More pictures from a Krupp catalogue