15 cm MRK L/30

15 cm MRK L/30 15 cm Kanone L 30 C 80 in Mittelpivot-Lafette 1890 91186---0022.jpg 300px A 15 cm MRK L/30 C/80 in 1890 German Empire yes yes yes German Empire Denmark Netherlands Krupp 1880 Krupp 1882 at least 28Brockhaus 1897 308 4,100 kgGalster 1886 Notizen, 12 4,470 mmGalster 1885 Notizen 204  mm 149.1 mm 495 m/sGalster 1886 Notizen, 17 The 15 cm Mantel Ring Kanone L/30, known as 15 cm Kanone L/30 was a 15 cm 30 caliber long Krupp Mantel Ring Kanone (MRK). It was a rifled breech loader built-up gun with a Krupp cylindroprismatic sliding breech. It was based on the later models of the 15 cm RK L/26, a 15 cm MRK L/28, and a 15.24 cm (6 inch) predecessor. This predecessor was the first of a new series of 30 and 35 caliber long guns that Krupp made to profit from a slower burning gunpowder invented in the early 1870s. Context In the race of ship armor against ship artillery, the primary course of action of the artillery manufacturers was to increase the caliber of their guns. As a second option, they attempted to increase the velocity to which the projectiles were propelled. This boiled down to increasing the charge of guns. There were several reasons why significantly increasing the charge of existing guns was very difficult.Sc 1880 693 One of the main problems that had to be overcome to increase the effectiveness of guns, was that an increase of the charge leads to an increase of the peak atmospheric pressure inside a gun. In other words, simply increasing charge of an existing gun leads to increased wear, and sooner or later, the bursting of the gun barrel. The first series of Krupp Ring Kanone overcame this problem by using the so-called Prismatic Pulver c/68 (P.P. c/68), a kind of gunpowder that burned slower than traditional gunpowder.Von Müller 1879 152 This is also called less-offensive. In the 1870s, manufacturing a less-offensive gunpowder could be done. The real challenge was in quality control. Gunpowder batches from the same manufacturer and having the same specifications could lead to differences in average atmospheric pressure of 200-300 Atm. This made it very hard to develop a reliable less offensive kind of gunpowder.Sc 1880 694 In January 1872 the management of the Spandau gunpowder factory started to experiment with a kind of gunpowder that would finally lead to the even less offensive P.P. c/75 which had a density of 1.75 and only one channel. In October 1875, the Allgemeines Kriegs Departement approved its use under the P.P. c/75 designation.Von Müller 1879 150 Related, earlier guns The 15 cm RK L/26 15 cm RK L/26 By 1874, the German Navy already had a relatively long gun with a high velocity, the 15 cm RK L/26. This had seen a problematic development. After first getting ordered in 1869, its rifling and driving bands were only determined in 1873/74.Von Müller 1879 142 By 1875, the latest Krupp innovations were the Mantel Ring Kanone construction,Von Müller 1879 259 copper driving bands, parallel grooves, and a rifled chamber.Sc 1880 695Von Müller 1879 160 In July 1878, a 15 cm L/26 gun was tested at the Krupp artillery range in Meppen.Van der Mandele 1878 29, Bijlage IV Known differences with the original 15 cm RK L/26 were: the rifled chamber, the 36 parallel grooves with 3.5 mm wide lands, copper driving bands, and a progressive twist length of 6.71 m (L/45).Van der Mandele 1878 29, Bijlage IV A shorter MRK (the 15 cm MRK L/22) had been ordered in Summer 1877.Von Müller 1879 264 One can therefore suppose that this L/26 was also a Mantel Ring Kanone (hooped & jacketed), but this is not certain. The projectiles fired by the 15 cm L/26 during this test weighed 31.5 kg. The charge was 9.5 kg of roughly granulated (pebble) powder of 13–16 mm or 8.5 kg of prismatic powder with 7 channels and a density of 1.64. The velocity measurement failed.Van der Mandele 1878 29, Bijlage IV However, from a May 1878 test it was known to be 500–514 m/s.Van der Mandele 1878 67, Bijlage IV The other guns at this test (35.5 cm MRK L/25, 30.5 cm MRK L/25, and 28 cm MRK L/22) used gunpowder with a density of 1.75 and one channel, which conforms to P.P. C/75.Van der Mandele 1878 29, Bijlage IV The July 1878 test showed that Krupp first lengthened its heavy 35.5 and 30.5 cm guns to profit from the new P.P. C/75 type of less offensive gunpowder. This could be related to Krupp's attempt to create a 15 cm armored gun, the so-called de Panzerkanone. This was tested as a 15 cm gun in 1877 and also in July 1878, when it had a caliber of 15.5 cm. Both tests took place in Bredelar.Van der Mandele 1878 1, Verslag The 15 cm MRK L/28 Designing a 15 cm MRK for a heavier charge sounds easier than it was. If the charge of the gun was to be higher, the chamber of the gun had to be lengthened to give the gunpowder the same relative space to expand. Therefore, increasing the charge by itself would increase the length of the gun.Sc 1880 694 If the charge was increased by using less offensive gunpowder, then it was very likely that the projectile would leave the barrel before all the gunpowder has exploded. Therefore, the barrel had to be lengthened on both sides to fully profit from less offensive gunpowder.Sc 1880 694 When the July 1878 tests took place, the regular length of projectiles was 2.8 or at most 3 calibers long. It was clear that longer, i.e. heavier projectiles would have more punch than shorter ones. Longer projectiles would also loose less velocity due to drag than lighter ones. However, longer projectiles were prone to be misformed in the barrel, to have an unsure flight, or to hit at a wrong angle. Longer projectiles also required a stronger charge, a faster twist rate, and a stronger carriage. The latter because of the higher and or longer recoil. Taken together this meant that effective use of longer projectiles required a totally new design.Sc 1880 696 In December 1878, Krupp had a 15 cm L/28 gun ready. It weighed 3,960 kg and had a progressive twist rate of 25 calibers or 3.73 m (giving the projectile a faster twist). In January 1879, it fired a 4 caliber long 50 kg grenade with a charge of 15.5 kg of gunpowder of 1.75 density. Velocity was about 510 m/s, but if the older lighter grenades were used this could become 630 m/s.Sc 1880 697 During 1879, the 15 cm MRK L/28 proved the theory that longer projectiles were very useful, especially because these did not lose their punch at a distance.Sc 1880 698 In August 1879, the 15 cm L/28 was tested in Meppen. With strong winds of 7.64 m/s the longer projectiles proved to remain accurate. The gun fired an armor piercing grenade of 51 kg at a velocity of 509 m/s and a regular grenade of 40 kg at 559 m/s. At 1,979 m from the muzzle the former had a velocity of 395 m/s, the latter had 396 m/s.Meppen 1879 517 The 15.24 cm MRK L/30 thumb|15.24 cm (6 inch) MRK L/30 Based on the results of tests with smaller guns, the 15 cm L/28 and the 25 caliber long guns of larger calibers, Krupp designed a whole new system of 30 and 35 caliber long guns, the so-called Construction 1880 or c/80. The 15 cm guns would have a caliber of 14.91 cm and would come in a two 25 caliber versions, a 30 caliber version, and a 35 caliber long version.Sc 1880 699 However, the first 15 cm L/30 gun that Krupp actually made had a caliber of 152.4 mm (i.e. 6"). Its consistent name could have been 15 cm MRK L/30. There were several possible grounds why Krupp first made a 15 cm L/30 gun: The 15 cm caliber was in general use on ships and as a coastal gun; It was only a small step from the L/28; and a 15 cm L/30 could be made easier and with less cost than a heavier gun.Sc 1880 701 The strange caliber of 15.24 cm was not in line with the 14.91 cm of the c/80 system.Sc 1880 700 There were suspicions that Krupp chose the caliber to provide a clear comparison to a new British 6 inch gun.Sc 1880 701 However, it is not that clear that Krupp designed this gun after the c/80 system had been designed. In 1884, both seem to appear in an overview as: '30 Kaliber lange 15 cm Kanone'. One of them has the suffix C/80 and fired a 51 kg projectile. The gun without the suffix fired a 50 kg projectile.Pucherna 1884 292 It is also possible that something went wrong while boring / rifling a 14.91 cm gun, and that it was simply bored up to the next logical caliber. The new 15.24 cm MRK L/30 had a caliber of 152.4 mm (i.e. 6"). It was 4,600 mm long (L/30) with a length of bore of 4,180 mm (L/27.5). The chamber was rifled. It had 36 parallel grooves with a progressive twist rate of 3.81 m or L/25. Its weight including the breech was 4,200 kg.Sc 1880 701 In July 1880, this gun was tested in Meppen. It fired a 50 kg grenade with a velocity of about 520 m/s. A 35 kg grenade was fired with a velocity of about 615 m/s.Sc 1880 701 The 15 cm MRK L/35 15 cm MRK L/35 In March 1882, Krupp tested a 35 caliber long 15 cm MRK L/35 in Meppen.Schwarz 1882 389, 391 It fired 3.35 caliber long armor piercing grenades and 4 caliber long explosive grenades. Each weighed 51 kg. The charge was 17 kg of gunpowder with a density of 1.75 and a single channel. Velocity was about 535 m/s.Schwarz 1882 391 The 15 cm MRK L/35 again had the regular Krupp caliber of 14.91 cm.Schwarz 1882 391 The 15 cm MRK L/30 When Krupp tested the 30.5 cm MRK L/35 and the 15 cm MRK L/35 in March 1882, there was no L/30 present. A specific mention of a 15 cm L/30 gun noted that a 152.4 mm caliber gun had been tested.Schwarz 1882 394 Therefore, we have to look for the development and first test of the 15 cm MRK L/30 in the timeframe between March 1882 and February 1883. Testing brown gunpowder On 27 February 1883, a 15 cm MRK L/30 was tested in Meppen. It used about 16.5 kg of the new 'brown prismatic gunpowder C/82'. The projectiles it fired weighed about 51.5 kg. With high charges, velocity was between 524 and 549 m/s. The gas pressure inside the gun was between 2,265 and 2,705 Atm.Düneberg 1884 100 On 8 May 1883 further tests took place in Meppen. This time the caliber of 149.1 mm was explicitly mentioned. The gun fired 5 projectiles weighing 51 kg with a charge of 15 kg of brown gunpowder C/82. Velocity was 505 m/s at the muzzle and 392 m/s at 2,000 m. Gas pressure was between 2,280 and 2,500 Atm.Düneberg 1884 102 The same ballistic results could be reached by using 16 kg of C/75, but then peak gas pressure was about 200Atm higher.Düneberg 1884 97 In the German navy In 1885, the 15 cm MRK L/30 appeared in a list of the German navy's guns as 15 cm Kanone L/30, abbreviated 15 cm K. L/30.Marineverordnungsblatt 1885 2 Labels In the German navy, the 15 cm MRK L/30 was known as 15 cm Kanone L/30, abbreviated 15 cm K. L/30. At the time, the Mantel Ring Kanone construction was the latest. Therefore, in 1885 all Mantel Ring Kanone were relabelled as 'Kanone'. E.g. the 15 cm MRK L/22 became the '15 cm Kanone L/22'. The older Ring Kanone retained the label 'Ring Kanone'.Marineverordnungsblatt 1885 2 About 8 years later, something similar happened. When the quick-firing Mantel Ring Kanone or 'Schnellade Kanone' were introduced, the newer guns received the 'Schnellade Kanone' or 'SK' label, while the older ones retained the 'Kanone' label. Characteristics The gun The 15 cm MRK L/30 barrel had a caliber of 149.1 mm and weighed 4,100 kg, including the breech block of 420 kg.Galster 1886 Notizen, 12 The barrel was 4,470 mm long. There were 36 parallel grooves of 1.5 mm depth and 9.5 mm width. The lands were 3.5 mm wide. The progressive twist rate was L/25, meaning that the projectile made a complete turn while travelling that distance.Galster 1885 Notizen 204 The barrel had a length of bore of 4,050 mm. From the back, this consisted of: The unrifled part of the chamber, where the charge was placed, this was 650 mm long. Next came an de Ubergangskonus of 139 mm. The length of the rifled part of the chamber was again 650 mm. The rest of the barrel was 2,611 mm long.Galster 1885 Notizen 204 Carriage The 15 cm MRK L/30 was mounted on the 15 cm Rahmen Lafette C/83 and the 15 cm Mittel Pivot Lafette C/83.Marineverordnungsblatt 1885 14 The 15 cm Rahmen Lafette C/83 was a slide carriage, the upper part weighed 890 kg, this stood on a slide of 1,270 kg. When the gun was fired, the recoil moved the upper carriage back on the slide, which contained a brake. The firing height was 965 mm. Elevation up to 15 degrees, declination 6 degrees.Galster 1886 Notizen, 12 The 15 cm Mittel Pivot Lafette C/83 was also a sliding carriage. The difference was that the slide was turned on a pivot near its center, instead of near the muzzle of the gun. The firing height was 1,095 mm. Elevation was up to 20 degrees, declination 5 degrees.Galster 1886 Notizen, 12 Projectiles The 15 cm MRK L/30 could fire the old 2.8 caliber long projectiles as well as the new 3.5-4.5 calibers long grenades.Almanach 1892 60 Early on, the 15 cm MRK L/30 used the 15 cm Granate L/4 (or Granate C/82), and the Stahlgranate L/3.5 (or Stahlgranate C/82). These were shot with a charge of 15 kg of Prismatic Pulver C/75. The projectiles weighed 51 kg and had a conic driving band without indentation and had a centration wart.Marineverordnungsblatt 1885 28Galster 1886 Notizen, 17 The German navy used a charge of 15 kg of P.P. C/75. With that charge, velocity was 495 m/s.Marineverordnungsblatt 1885 29Galster 1886 Notizen, 17 Later, the 15 cm MRK L30 C/80 used a charge of 17 kg. With that charge, the light L/2.8 steel grenade attained a velocity of 590 m/s. The heavy L/4 attained a velocity of 525 m/s.Almanach 1892 62 Use German Navy In 1897 the Carola corvette 1s Arcona 1885 6 and Alexandrine still had 15 cm Mantel Ring Kanonen L/30.Brockhaus 1897 308 The Irene cruiser 1s originally had six 15 cm Mantel Ring Kanonen L/30, and eight 15 cm MRK L/22.launched 1888 316 By about by 1897 these had been replaced by four 15 cm SK L/30, eight 10.5 cm SK L/30, and six 5 cm SK L/40 gun.Brockhaus 1897 308 Apart from this, it is known that some older 15 cm guns were changed to become 15 cm MRK L/30.Galster 1885 Notizen 204Galster 1886 Notizen, 12 German Army 15 cm Ring Kanone L/30 In time, the ships that mounted the 15 cm MRK L/30 were retired or re-armed. The barrels were obviously stored, because in World War I, some guns were taken out of storage and mounted on simple land carriages. These guns were known as 15 cm Ring Kanone L/30. Danish coastal artillery In the mid-1880s, Denmark acquired 11 15 cm MRK L/30 guns for its coastal artillery. These fired 51 kg armor-piercing grenades. With a charge of 17 kg of brown prismatic gunpowder these acquired a velocity of 540 m/s.D. 1887 67 Dutch coastal artillery The Dutch coastal artillery, which was part of the army, used the 15 cm MRK L/30 in the coastal Fort IJmuiden and at the coastal Fort Hoek van Holland. In both forts it was placed in an armored cupola.KMA 1887 105 Further development In 1885, the 15 cm MRK L/30 and 15 cm MRK L/35 were very efficient guns. This was measured in terms of the punch they delivered in relation to their weight.Waffenschmied 1885 47 However, the future was with Quick-firing guns like the 15 cm SK L/35. Notes 2 References 1892 Almanach für die K. und K. Kriegsmarine II. Theil Artillerie der verschiedenen Flotten Redaction der Mittheilungen aus dem Gebiete des Seewesens, Pola https://books.google.com/books?id=xA5KrIcBDQYC 33–78 Almanach 1892 1897 XVII Brockhaus' Konversations-Lexikon Brockhaus, Leipzig, Berlin, Wien https://books.google.com/books?id=z6EfR2bk6eYC Brockhaus 1897 D. 1887 Jahresberichte über die Veränderungen und Fortschritte im Militärwesen Heerwesen Dänemarks. 1887. Mittler und Sohn, Berlin 60–68 https://books.google.com/books?id=4g4fa6N8GjkC 1887 Beknopt overzicht der proeven en oefeningen, die in het jaar 1886 hebben plaats gehad Koninklijke militaire Academie, Breda https://books.google.com/books?id=OV0iCfE7Wb4C KMA 1887 1884 Mitteilungen über Gegenstände des Artillerie- und Geniewesens Versuche mit prismatischem Pulver, erzeugt in der Fabrik Düneberg bei Hamburg R. von Waldheim, Wien Notizen: 96–110 https://books.google.com/books?id=6uQiMYsM8p4C Düneberg 1884 Galster Karl 1885 Mitteilungen über Gegenstände des Artillerie- und Geniewesens Nach: Die Schiffs- und Küstengeschütze der deutschen Marine R. von Waldheim, Wien Notizen: 202–204 https://books.google.com/books?id=VxC1IpAU2CoC Galster Karl 1886 Mitteilungen über Gegenstände des Artillerie- und Geniewesens Nach: Die Schiffs- und Küstengeschütze der deutschen Marine R. von Waldheim, Wien Notizen: 11–18 https://books.google.com/books?id=M8ysUav4O2AC Van der Mandele H.J. 1878 Mededeelingen Betreffende Het Zeewezen III Verslag betreffende de proeven met geschut .. te Bredelar en te Meppen Van Cleef 's Gravenhage https://books.google.com/books?id=s3pMAAAAYAAJ 1885 Marineverordnungsblatt Zusammenstellung der in der Marine-Artllerie vorhandenen gezogenen und glatten Geschüssrohre in Bezug auf Bennenung un Schreibweise Kaiserlichen Admiralität, Berlin 39–44 https://books.google.com/books?id=fmWGQUsHPzcC Marineverordnungsblatt 1885 1879 Mitteilungen über Gegenstände des Artillerie- und Geniewesens Krupp'sche Gussstahlfabrik, Schiessversuche bei Meppen im August 1879 R. von Waldheim, Wien 481–544 https://books.google.com/books?id=wjCjkhxZVyIC Meppen 1879 1888 Naval Reserves, Training, and Matériel Germany, vessels launched Office of Naval Intelligence 315–317 https://books.google.com/books?id=1ZgDAAAAYAAJ launched 1888 Von Müller Hermann 1879 Die Entwickelung der preußischen Küsten- und Schiffs-Artillerie von 1860-1878 Robert Oppenheim, Berlin https://books.google.com/books?id=bxrezKOhiq4C Pucherna W. 1884 Mittheilungen aus dem Gebiete des Seewesens Uber die Erhöhung der Geschützwirkung K.K. Hydrographischen Amte, Marine-Bibliothek, Pola 280–295 https://books.google.com/books?id=a2Q2AQAAMAAJ Sc 1880 Mittheilungen aus dem Gebiete des Seewesens Die Neuere Schiffs- und Küstengeschütze der Krupp'schen Gussstahlfabrik K.K. Hydrographischen Amte, Marine-Bibliothek, Pola 693–706 https://books.google.com/books?id=Y_A5AQAAMAAJ Schwarz Jos. 1882 Mittheilungen aus dem Gebiete des Seewesens Schiessversuche der Fr. Krupp'schen Gusstahlfabrik im März 1882 K.K. Hydrographischen Amte, Marine-Bibliothek, Pola 389–397 https://books.google.com/books?id=fkYrAwK2egcC 16 December 1885 Der Waffenschmied: Zentralblatt für die gesammte Waffenfabrikation Killinger, München https://books.google.com/books?id=BKDRZBCj1sYC Waffenschmied 1885 Category:Naval guns of Germany Category:Naval guns of the Netherlands Category:Krupp naval guns Category:Military equipment introduced in the 1880s