152 mm 45 caliber Pattern 1892

The 152mm 45 caliber Pattern 1892 was a Russian naval gun developed in the years before the Russo-Japanese War that armed a variety of warships of the Imperial Russian Navy during the Russo-Japanese War and World War I. Guns salvaged from scrapped ships found a second life on river gunboats of the Soviet Navy during the Russian Civil War and as coastal artillery and railway artillery during World War II. In 1941 It was estimated that there were 196 guns (82 in the Baltic, 70 in the Pacific, 37 in the Black sea and 7 in the Northern fleet) still in use as coastal artillery. After independence in 1917 Finland was estimated to have inherited 100 guns and some remained in use until the 1980's.

History
In 1891 a Russian naval delegation was shown three guns designed by the French designer Canet. One was a 75/50 gun caliber gun, one was a 120/45 gun, and the last was a 152/45 gun. All three guns used fixed QF ammunition which produced a rate of fire of 15 rpm for the 75/50 gun, 12 rpm for the 120/45 gun and 10 rpm for the 152/45 gun. The Russians were impressed and in 1892 they negotiated a production license for all three guns. In practice the rate of fire of 10 rpm was hard to achieve due to difficulties with ammunition handling. The practical rate of fire varied by class of ship from a low of 2 rpm in the Petropavlovsk-class battleships, to a high of 7 rpm in single deck mounted guns. In 1901 the fixed ammunition was changed to separate loading QF cased charge and projectile.

Construction
There were two main series of the 152/45 guns produced. The first series of guns were constructed of a thick A tube, a 3.2 m long B tube and jacket. 215 of the first series of guns were built between 1897-1901, 181 at the Obhukov factory and 37 at the Perm factory. During the Russo-Japanese war a number of gun barrels burst in action and a strengthened series of 133 guns were produced, 21 at the Obhukov factory and 112 at the Perm factory between 1909-1918. The strengthened series of guns had a thinner A tube reinforced with three sections of B tube and a jacket which was 4 m long.

Naval Use
The 152/45 guns armed the majority of armored cruisers, pre-dreadnought battleships and protected cruisers of the Imperial Russian Navy built between 1890-1916.

Armored Cruisers Gunboats Pre-dreadnought Battleships Protected Cruisers
 * Admiral Kornilov - This ships primary armament consisted of five, 152/45 guns, per side, in single mounts after a 1905 refit.
 * Bayan-class - This class of four ships secondary armament consisted of four, casemated, 152/45 guns, per side, in single mounts, amidships.
 * Dmitriy Donskoi-class - The primary armament of Dmitrii Donskoi consisted of six, 152/45 guns, in single mounts after a 1895 refit. The primary armament of Vladimir Monomakh consisted of five, 152/45 guns, in single mounts after a 1897 refit.
 * Minin - The primary armament of this ship consisted of three, casemated, 152/45 guns, per side, in single mounts after a 1893 refit.
 * Rurik-class - The secondary armament of Gromoboi, Rossia and Rurik consisted of eight, casemated, 152/45 guns, per side in single mounts.
 * Khrabryy - The secondary armament of this ship consisted of one 152/45 gun.
 * Korietz-class - This class of nine ships secondary armament consisted of one 152/45 gun.
 * Borodino-class - This class of five ships secondary armament consisted of six, 152/45 guns, per side, in twin gun turrets, amidships.
 * Ekaterina II-class - Two ships of this class were refitted with 152/45 guns. Sinop was refit with twelve single mount guns as secondary armament in 1909.  Georgii Pobedonosets was refit with fourteen single mount guns as secondary armament in 1909.
 * Evstafi-class - This class of two ships tertiary armament consisted of six, casemated, 152/45 guns, per side, in single mounts, amidships.
 * Imperator Aleksandr II - This ships tertiary armament consisted of four, casemated, 152/45 guns, per side, in single mounts, amidships after a 1904 refit.
 * Peresvet-class - This class of three ships secondary armament consisted of five, casemated, 152/45 guns, per side, in single mounts, amidships. One more gun was in a casemate in the bow.
 * Petropavlovsk-class - This class of three ships secondary armament consisted of four, 152/45 guns, per side, mounted in twin turrets, amidships. Two more casemated guns were in single mounts, amidships.
 * Petr Veliky - This ships secondary armament consisted of twelve 152/45 guns after a 1907 refit.
 * Potemkin - This ships secondary armament consisted of eight, casemated, 152/45 guns, per side, in single mounts, amidships.
 * Retvizan - This ships secondary armament consisted of six, casemated, 152/45 guns, per side, in single mounts, amidships.
 * Rostislav - This ships secondary armament consisted of four, 152/45 guns, per side, in twin turrets, amidships.
 * Sissoi Veliky - This ships secondary armament consisted of three, casemated, 152/45 guns, per side, in single mounts, amidships.
 * Tri Sviatitelia - This ships secondary armament consisted of four, casemated, 152/45 guns, per side, in single mounts, amidships.
 * Tsesarevich - This ships secondary armament consisted of six, 152/45 guns, per side, in twin gun turrets, amidships.
 * Askold - This ships primary armament consisted of twelve 152/45 guns in single mounts.
 * Bogatyr-class - This class of four ships primary armament consisted of four, 152/45 guns, in twin turrets fore and aft. Another four casemated guns, per side, were in single mounts, amidships.
 * Pallada-class - This class of three ships primary armament consisted of eight 152/45 guns.
 * Svetlana - This ships primary armament consisted of one 152/45 gun for and aft. Another two casemated guns, per side were in single mounts, amidships.
 * Varyag - This ships primary armament consisted of twelve 152/45 guns in single mounts.

Finnish use
As Finland became independent the northern half of the coastal fortifications in Imperial Russian Peter the Great's Naval Fortress fell in to Finnish hands mostly intact. The coastal guns included about 100 pieces of the 152 mm 45 caliber Canet guns and this type became the primary coastal gun of its class in Finland. It was given a designation of 152/45 C. There was considerable variation between the guns as they included both naval and army coastal gun models from different years. There were also different gun mountings used with about 70 guns on taller coastal gun mountings but the remaining 30 guns were on lower ship deck mounts with lower maximum elevation and range.

Finnish coastal artilery made modifications to the gun mountings during the interwar period. The most significant of these was inverting the gun so that the recuperating spring was on top of the gun which allowed increasing the maximum elevation and thus the range. Inverting the gun however required also strengthening the recuperator, adding an equilibrator to correct the changed balance and other changes to the mounting and elevation mechanism. Increased maximum elevation also allowed using the gun as an anti-aircraft weapon. To increase maximum range even more the ammunition for the guns was modified by adding a ballistic cap to existing ammunition which increased the range by a factor of 1.5. Additionally Finns changed the gun loading practice to allow reloading without the need to return the gun to zero elevation after each shot. This practice increased the rate of fire.

During World War II 152/45 C was the de facto Finnish standard coastal gun with 95 guns in the inventory at the beginning of 1939. During Winter War coastal batteries equipped with the gun defended against Soviet Navy attacks before the sea was frozen. The guns also provided important artillery support for the Finnish army: at both ends of the Mannerheim line were coastal batteries equipped with 152/45 C guns, and their role was important given the Finnish lack of field artillery. Other coastal batteries in the northern part of Lake Ladoga also supported land battles, and later in the war coastal forts in Gulf of Vyborg and Kotka participated in the fighting. 18 guns were lost during the war, most when the coastal forts had to abandoned. 76 guns remained in use after Winter War.

During the Interim Peace Finland began constructing Salpa Line to fortify the new border to replace Mannerheim Line fortifications. Salpa Line artillery included six 152/45 C guns. In the Continuation War 152/45 C was involved in the fighting again and several guns were lost to barrel explosions or simply worn out. Some guns lost in the Winter War were recaptured bringing the total to 78 pieces in 1943. By the 1st of May 1944 the number had dropped to 60. During World War II 152/45 C guns were also used as anti-aircraft guns. The guns, designed originally before aircraft had been invented, were not especially effective in this role even after the modifications that had been done. Despite the limitations they were used againts enemy bomber formations, especially in the defense of Helsinki and also against fighters. Finland also used 152/45 C guns as railway guns. The first trials with a 152/45 C gun mounted in a railway wagon in Finland was performed in 1924 and the gun was given the designation of 152/45 CRaut. Winter War mobilization plans called for two gun railway battery, but due to equipment problems only a single gun was available for most of the war. In Continuation War the battery was expanded to four guns. On 21.9.1941 the battery was renamed as 2nd railway battery after 1st railway battery had been formed from captured Soviet 180 mm railway guns. The battery was disbanded and the guns removed from the railway wagons after the war, but the plans for re-forming it remained in place. In 1962 there were three guns reserved for forming a railway artillery battery.

After the Continuation War ended with Moscow Armistice Allied Control Commission demanded that all coastal guns larger than 120 mm in calibre east of Porkkala had to be removed and placed in storage. This included the coastal fortifications around Porkkala, fortifications of the capital Helsinki (18 152 mm guns) and the Kotka-Hamina area forts (17 152/45 C guns). This restriction was lifted in 1947 after signing of the Paris Peace Treaty. 152/45 C guns were badly worn out after the war, and several had cracked or broken barrels. An investigation of the barrel failures concluded that the guns could not withstand the pressures created by the gunpowder used. This led to a development of a new light weight high explosive shell which could be fired by a half-charge of gunpowder. The worn out gun barrels were replaced with newly developed 50 caliber 152 50 Tampella barrels.

152 50 Tampella
Already near the end of the World War II Tampella company was ordered to construct new gun barrels for 152/45 C guns. Due to the end of the war this did not happen, but in the early 1950s there was again available funds to start modernizing the guns. Tampella barrel was longer than the original at 50 calibers and it had different, progressive rifling with 48 1.25 mm deep grooves instead of the original constant 38 1.0 mm deep grooves. Due to these changes the modernized gun could not use the ammunition of the original guns and new ammunition was developed for it using cartridge cases. The maximum range of the modernized gun was 25 km. The new barrels were also equipped with muzzle brakes. The new guns were given the designation 152 50 T and they started equipping coastal batteries in 1959. A total of 29 guns were built. In 1960s concern for the vulnerability of fixed guns against napalm led to adding a protective metal cupola for the guns. An overpressurization system was also fitted. The cupola was built of thin metal and provided only very limited armour protection against small shrapnel. Smaller changes to the gun mounting were also made, including replacing the recoil springs. The modernized guns replaced older 152/45 C guns but some original models remained in less important positions. Bolax battery is unique where the cupola armour was fitted but the guns themselves were not modernized. By 1980s the 152 50 T was in turn being replaced with 130 53 TK and they were withdrawn from service in 2003.

Ammunition
Ammunition was of separate QF type with a cased charge and projectile. The projectiles weighed 41.4 kg and the charge weighed 12 kg.

The gun was able to fire:
 * Armor Piercing
 * Chemical
 * Common
 * High Explosive
 * Illumination
 * Incendiary
 * SAP
 * Shrapnel