Mid 18Th Century Prussian Chambered Guns
Total Page:16
File Type:pdf, Size:1020Kb
SOJ-6(08) Mid 18th Century Prussian Chambered Guns From 1738, Prussian field cannon became much lighter so were more mobile than the M1717 heavy ordnance. The reasons behind this include. 1. The reduction in the charge weight permitted the metal strength of the gun tubes. 2. The improvement in gunpowder permitted the use of shorter barrels with similar muzzle velocities. 3. A chambered bore design was believed to create much more gas pressure then an ordinary bore design. 4. More guns could be produced from the same amount of bronze. 5. The introduction of cadence to Prussian infantry drill had increased their mobility on the battlefield and so required an equally mobile artillery for a improved close range. Frederick was so enthusiastic about these light pieces, that within a decade, all of the old heavy ordnance was rigorously melted to provide the gunmetal for new casts, or placed in arsenals to serve as fortress or siege cannon. By 1756, all Prussian field guns coming out of the foundries were chambered bore pieces, mostly of a length of 16 calibres. There were also a new14 calibres 12-pdr and a super light 12 calibres 24- pdr. The Beauvry 3-pdr was the single ordinary bore design remaining. Prussian 18th Century Artillery, SOJ-6 Page 36 M1740 Holtzmann Conical Chambered Guns In 1738, Oberst-Lieutenant Ernst Friedrich von Holtzmann (II)67 design 3-, 6- and 12-pdr barrels with a cylindrical chamber for the gunpowder charge with a bore of 15.6 D long. These were first cast in 1740. The barrel axis ( i.e. the vertical line dividing the trunnion in half) was placed at 3/7 of the length of the bore plus 1 part. The first reinforce was equal to twice the length of the second reinforce plus 0.5 D.68 M1740 Holtzmann Conical Chambered 3-pdr The barrel was calculated for a powder charge of 0.35 kg. Holtzmann calculation were based upon a 2-pdr shot diameter (62.8mm) as basic scale and divided these into 24 parts (1 part=2.62mm). It was believed that the metal strength of the rear of the barrel should equal the diameter of an iron shot double the weight of the powder charge. This held true for a barrel of 24 shots length and proportionally less for shorter barrels. At this point, now, matters became subject to personal belief or understanding, and as a result, the design of the Prussian barrels worked with as many figures as there were Prussian gun designers during this period. M1740 Holtzmann Conical Chambered 3-pdr barrel [Christian Rogge] The barrel design for the M1740 Holtzmann Conical 3-pdr had a metal strength based upon the 2-pdr shot diameter (62.8mm): 1st reinforce thickness 20 parts [52.33mm] to 19 parts [49.7mm] 2nd reinforce thickness 17 parts [44.5mm] to 16 parts [41.9mm] Chase thickness 14 parts [36.6mm] to 10 parts [26.2mm] Height of the muzzle swell 9 parts [23.6mm]] Muzzle length 2¼ D long [141.3mm] Cascable and button length 1.5 D long [94.2mm] The conical chamber bore narrowed to 16 parts [47.9mm] of the diameter of the 3-pdr shot [71.9mm]. Illustrated volume arrives at 0.594 litres/cubic decimetres including allowance for the rounds canvas or tin case and insulating material.69 67 Promoted Oberst in 1756 and Commander of the 2nd (Silesian) Artillery Battalion. Died in 1759. 68 Malinowsky & Bonin, Geschichte der brandenburg–preussischen Artillerie, vol. II, Berlin 1841. 69 Specific gravity of gun powder calculated with a middled 0.925, based on former Hanoverian figures of 1 Hanover/Calenberg scale cubic foot holding 47 lb of gun powder or 51 lb of water – the latter equalling 1. Prussian figures are slightly larger, or 60 lb to the larger Berlin cubic foot, as per the same source [Scharnhorst, Militärisches Taschenbuch zum Gebrauch im Felde, Hanover, 1793]. Prussian 18th Century Artillery, SOJ-6 Page 37 M1740 Holtzmann Conical Chambered 3-pdr on M1717 Carriage. [Christian Rogge] This piece used the M1717 carriage model in service into the Seven Years War and beyond until the universal adoption of the modified M1766 model carriage. The wheels of the carriage measured 110 cm [42 Berlin Zollen]. The tracks was 136 cm [52 Berlin Zollen] wide. Table 5: Prussian M1740 Holtzmann cylindrical 3-, 6-, 12- and 24-pdr dimensions M1740 Holtzmann M1740 Holtzmann M1740 Holtzmann M1740 Holtzmann M1744 Holtzmann Cylindrical Cylindrical Cylindrical Cylindrical Cylindrical 3-pdr 6-pdr Light 12-pdr 24-pdr 24-pdr “Steinstück” Bore 73.2mm 94.2mm 119mm 149.9mm 149.9mm Calibre 71.9mm 90.6mm 114mm 143.9mm 143.9mm Shot 1.4kg 2.8kg 5.6kg 11.2kg 11.2kg solid shot 8.14kg shell Length 115cm 145cm 182cm 230cm 173cm L/16 L/16 L/16 L/16 L/12 Length ratio 9kg/D 14kg/D kg/D kg/D Weight 240-247kg 420-462kg 560-588kg 1680-1848kg 672kg Weight ratio 150-165:1 150-165:1 150-165:1 150-165:1 60:1 Chamber Cylindrical Cylindrical Cylindrical Cylindrical Cylindrical Charge 0.35kg 0.7kg 1.4kg 2.8kg 1.8kg Charge ratio 1:4 1:4 1:4 1:4 1:6 Horses 3-4 horses 3 horses 4 horses 6 horses 4 horses Cast in Berlin 160 in 1742 2 in 1743 20 in 1742 8 in 1743 1 in 1744 29 in 1743 20 in 1743 8 in 1745 in Wesel None None None None 4 in 1744 12 in 1745 in Breslau 44 in 1743 None 2 in 1742 None None 24 in 1745 TOTAL Prussian 18th Century Artillery, SOJ-6 Page 38 Holtzmann M1744 Cylindrical Light 24-pdr [Stein-Stück] In 1744 by Oberst-Lt Ernst Friedrich von Holtzmann designed the M1744 Light 24-pdr with cylindrical chamber of 4 to 4.5 pfund [? kg]. It was often referred to as the Stein-Stück [‘stone piece’]. It was a very early example of a shell gun or gun/howitzer that probably influenced the design of the Russian Shuvalov Unicorns of the 1750s. The piece was designed to fire conventional canister, Klemmkartätschen [specialized grape rounds of Holtzmann's invention], and hollow hollow shell of 18 pfund [? kg] weight. With the latter, it was intended to reduce the weight of the ammunition supply, as well as to reduce the force of the recoil. The Klemmkartätsche (grape) consisted of a solid cylindrical wooden box holding six iron 3-pdr shot diameter (7.19 cm). The rear was conical shape to adapt to the shape if the chamber bore of the piece. Holtzmann M1744 Cylindrical Light 24-pdr barrel.70 [Christian Rogge] The design was very similar to the Holtzmann M1744 Long 10–11-pdr howitzer Stein–Kartaune. Accordingly, its principal proportions were as follows: Barrels axis point 4/9 plus 3 p from the rear end. 1st reinforce length 2/3 the length from the axis to the rear of barrel 2nd reinforce length 1/3 plus half the trunnion diameter (1 D). Length of muzzle 2 D. Cascable and button length 1.5 D. 1st reinforce metal thickness 16 parts equal the diameter of the chamber 2nd reinforce metal thickness 12 parts. Chase 10 parts to 8 parts. Muzzle swelling +10 parts The measures indicated for the carriage are all expressed relative of the size of shot (D). As per M&B, vol. ii, p. 173, the carriages had a straight lower face. The front section was perfectly square shaped, the centre sections lower face was placed 2 zollen upwards the planks lower edge, thus, taking a good deal off the rounding of the trail. The metal fittings included an extra vertical sheet on the front and centre section (b). The front hook plate (a) linked with the first 3 horizontal bolts, reaching as far as the centre section of the carriage. In all, much resembling the pre 1717 metal fittings. Height of the wheels is believed to have been 51 zollen [ cm]. Track width was 4 fuss 4 zollen [ cm]. 70 The dimensions of the illustrated barrel are a tentative reconstruction based for the most part on the details found in Malinowsky & Bonin, Geschichte der brandenburg–preussischen Artillerie, vol. II, Berlin 1841 (M&B). Prussian 18th Century Artillery, SOJ-6 Page 39 Holtzmann M1744 Cylindrical Light 24-pdr [Stein-Stück] on M1717 carriage [Christian Rogge] Prussian 18th Century Artillery, SOJ-6 Page 40 M1740/47 Holtzmann Conical Chambered Guns During the Second Silesian War (1744-45), it was found that quarter powder charge inadequate to give the longer ranges required so that in 1747 all the M1740 Holtzmann Cylindrical barrels were rebored to give an increased conical chamber widened to 23 parts of the shot diameter (3-, 6- or 12-pdr) to take a powder charge of third the weight of the shot. Also in 1747, the Holtzmann Richtmaschine elevating device with iron screw replaced the somewhat simpler M1717 design wedges. From about 1752, iron trail rings were attached to the carriage that were used for moving and unlimbering the gun. These had first been introduced for Prussian battalion guns by the Linger design ‘20 D’ 3–pdr in 1752. M1740/47 Holtzmann 3-pdr In 1747, the charge was increased from a quarter powder charge [0.35kg] to a third the weight of the shot [0.47kg] by rebored the cylindrical chamber to a conical chamber and the Holtzmann Richtmaschine replaced the M1717 wedges [quorns]. From 1752, iron trail rings were attached to the carriage that were used for manhandling the piece in action were introduced.