Krupp 75mm mountain gun M. 1886

Bulgarian designation :75-мм нескорострелно планинско оръдие “Круп”Krupp designation :7,5cm Gebirgskanone L/13Calibre :75mm L/13Weight of the barrel :102 kgWeight of the carriage :157 kg (original carriage)244 kg (improved carriage adopted in 1892)Weight in action :259 kg with the original carriage346 kg with the improved carriageBarrel length :975 mmLength of the bore :845 mmLength of the rifled part :700 mm (9.4 calibres)Barrel groovesnumber :24depth :1.25 mmwidth :7 mmLength of twist :1875 mm (25 calibres)Height of the line of fire :660 mmBattering 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 shellweight :4.3 kg - charge : 94 g of gunpowdermax. range :4000 mShrapnel  C/88weight :4.355 kg – charge : 55 g of black powder85 bullets x 15 gmax. range :2200 mShrapnel  C/91weight :4.355 kg – charge : 55 g of black powder170 bullets x 11 gmax. range :2200 mCase shot :weight :4.2 kgmax. range :300 mMuzzle velocity :294 m/s with full charge152 m/s with reduced chargeRemaining velocity :228 m/s at 2200 m with shrapnel195 m/s at 4000 m with common shellAngle 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 mmElevation :+ 20° / - 10° (original carriage)+ 23° 12’ / - 6° (new carriage)Wheelsweight :55 kgtrack :0.83 mTransport :4 loads: 1 – barrel (130 kg); 1 – trail; 1 – wheels and shafts; 1 – two ammunition boxes weighting 48 kg eachAmmunition :in 1889 : 64 common shells, 40 shrapnel, 8 case shotsin 1912 : 138 shellsRemarks :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