Schneider-Canet 240mm L/45 QF gun



I. Features


The 240mm L/45 Schneider quick-firing coast gun was expecially designed as armament of upper batteries. Its distinctive feature is that it can be operated entirely by hands. Undoubtedly, at the present time war materials has seen an increasing employ of motive power, and also the firm Schneider & C. did not dropp back in this field. Nevertheless there is no denying that in the defence of the coasts there are a lot of particular instances where the installation of heavy weapons which required only the arms of its crew to operate is very profitable. Moreover, considering that this 240mm Schneider gun is a quick-firing piece, able to attain and sustain a rate of fire of 3 – 4 rounds a minute with trained gunners, no wonder that it had interested greatly the technical press, urging several governments to command it. The models put in service differ only in minor manufacturing details, that change neither their main features, nor their overall operation. As such, the following brief descrption is in principle appropriate, and suffices to give a complete idea of the gun.


II. Description


1st Gun-body. – The gun-body, in hardened annealing steel, is made along the ordinary manufacturing system of the firm Schneider & C. It is composed by a thick tube which runs the whole length of the gun, and  is strenghtened by a double hooping. The hooping of the first row included a set of short hoops between two long jackets : the B tube (rear jacket) is used to reinforce the opposition to the déculassement with its mass; the A tube concurs to ensure the hardness of the gun-body. The hooping of the second row is composed by a rear jacket and a set of short hoops.

The breech mechanism is of the interrupted screw type with pad obturator system De Bange. Its mechanism, operating by means of pinions and gears, enabled an extremely rapid manipulation. The repeat firing device could be used with electric and percussion tube, and is equipped with mechanical safety arrangements against premature fires and prolonged fires.

A blowing device, by means of the high pressure of the air, is able to dispel the gas remained in the bore after the departure of the shell. This device is connected with the operation of the breech, and works automatically at the beginning of the opening movement of the breech itself. Thence it assures a total safety against back-flash.


2nd Carriage. – The carriage is composed by the cradle, the slide, the bedding, the sighting and aiming gears, the service platform, the loading gear, the supplying mechanism, and the mask.

a) The cradle carrying the gun is made of cast steel, with bronze friction packing. It carries two hydraulic buffers with central controlling ram, and a compressed air run-out gear, with hydraulic joints. The buffers minimize and controll the gun recoil; during the recoil, the air of the run-out gear is subjected to a compression that leads the return to the run-up position. This movement is controlled by the work of the throttling bar of the piston rod, that operates to plug the hydraulic shock.

The cradle carries also : two trunnions; the firing gear, whom controlling mechanism (pistol grip) is placed near the aimer; the toothed arc, made in forged steel, and utilized to point in elevation; the sighting apparatus.

b) The slide carrying the gun-cradle structure is made in cast steel. It is composed by two trail cheeks joined to a round plate. The trail cheeks carry the trunnions of the cradle with the interposition of horizontal rollers. The plate form the upper roller path of the traversing movement, and has the support of the pivot.

The slide carries : two hooks, placed one forward, the other behind, in order to counter the rising up; the controlling mechanism of pointage, whom gears are lodged in bronze protective boxes; the joints of the mask; the joints of the service platfom.

c) The bedding carrying the slide is made in cast steel, and has the shape of a round plate. It is bolt on the battery terreplein by means of 24 bolts, that loan on a collar of the bedding. The slide rests on horizontal rollers, placed on a roller plate arranged on the bedding, and embraces also a vertical pivot coming from the foundry with the bedding, and furnished with a bronze friction ring. The bedding carries also the traversing toothed wheel.

d) The sighting gears. – The elevating apparatus is composed by a set of gears, controlled by a handwheel placed near the aimer, on the left side of the carriage, and activating a pinion geared with the toothed sector attached to the slide. The gun, thanks to it, can take in the firing angle corresponding to the distance from the target. An anti-friction mechanism inserted into the system prevents the trasmission of every kind of stress able to damage the gears. The connections between the gears were fixed in order to minimize the force required to point in elevation; to constantly lubrificate the rubbing parts greasing devices are provided; and the apparatus is irreversible since it has a worm wheel connected with an endless screw.

This apparatus complemented by a quick motion gear, that allowed to lower quickly the gun in loading position, at a – 5° 30’ angle, and to raise it back to the pointing position. The mechanism is controlled by a handwheel placed on the right side of the carriage, and controls the pinion of the elevating gear connected with the toothed sector, with the help of wheels lodged in a bronze protective box. A trasmission device, controlled by a pedal, allowed to connect at will the thoothed sector of the cradle, and therefore the gun itself, with both the elevating gear, and the rising mechanism. A very simple mechanical safety gear is provided, to prevent firing when the motion gear is utilized until the loading of the gun is not completed, and the motion gear is not connected with the elevating gear activated by the aimer.

The traversing apparatus is composed by a set of gears, controlled by a handwheel placed near the aimer on the right side of the carriage, and activating a pinion geared with the toothed sector of the bedding. All the arrangements introduced to assure the easy manipulation and the irreversibility of the gears of the elevating apparatus are utilized also for the traversing apparatus.

The sighting gears is fundamentally an arc sight, where is assembled a dial sight with reticle. The graduations are in millièmes of the range.

f) The service platform, firmly bolted on the joints of the slide, is composed by a metal framework; its frame comprised two strong longitudinal beams assembled by braces. Through rollers mounted on springs it is put on a roller plate concentric to the pivot of the carriage. Floorings with duckboards in strong wood are placed on the right side, on the left side and behind the platforom, for the gunners and the loading gear. The supplying mechanism is placed on the left side, behind the flooring of the aimer. Finally the apparatus has also access ladders and a balustrade.

g) The loading apparatus is composed by a conveyor and a thrower.

It was operated entirely by hands : it takes the projectile from the supplying place, carries it along the axle and in parallel with the axle of the gun, beforehand placed at a – 5° 30’ angle of descent, and brings it to its place in the chamber, without the need of using the rammer. The bag cartridges are charged by hands.

The conveyor is composed by a metal framework made by two vertical blades interlaced, and able to turn around a horizontal axle. Their supports are fixed at the service platform. The joints of the thrower frame are placed on the upper part of the conveyor.

It is controlled through a handle lever, which allows to turn the rotation axle. A spring connected on the one hand with a fixed part of the loading mechanism, and on the other hand with the conveyor, serves to slow down the movement of the conveyor when it carries the projectiles along the axis, and to speed up it when it goes to take the projectile at the suppling place.

The loader is composed by a frame joined at the conveyor and a revolving spoon.

The frame makes the roller path of the spoon. It carries a rod that engages automatically the loading apparatus with the gun or the supplying place : it can be disengaged only by hands.

The revolving spoon receives the projectile held by a stop bolt assembled between the belts; it is mounted on joints and provided with an automatic lubrificator to make easier the movement. A lever controlled by hands connects it with the frame, or unlocks it. Then an operating handle serves to throw it. It rolls on the inclined roller plate of the frame until it is stopped by the conical part of the chamber. At the same time, the stop bolt of the projectile goes down automatically. The projectile continues its moving by inertia with a sufficient speed to reach the cone, and stops there.

A safety lever connected with the lever of the spoon and the rod of the frame prevents from throwing the projectile when the conveyor is not assembled with the gun.

h) The supplying mechanism is composed by some wheelbarrows, a waiting place, a hoist and a supplying place.

The wheelbarrow consisted of a wooden shaft, two wheeles, an axletree, two lateral joints, and an iron platform covered with brass. The projectiles, got at the store, are placed on this platform, and are carried in this way to the waiting place. This mean of transport is rustic and dispenses with the installation of rails on the terreplein of the battery. It can work even in the even of a damage of the terreplein itself. The arrangements of the wheelbarrows were designed in order to make easy and rapid the loading and the unloading of the projectiles.

The waiting place, situated near the hoist, is invariably connected to it. It is a sort of box where the wheelbarrow can be bound, staying guided by its lateral joints, without being trained by the traversing movement, if need be. On the bottom of the box is arranged a grill formed by three curved blades covered with brass, where the gunner places the projectile, tipping its wheelbarrow. Then he comes back to the store with its wheelbarrow empty.

The hoist placed on the left side of the service platform, and firmly assembled to it, is a kind of noria. It is composed by a sheet metal framework carrying two shafts : the lower shaft is operated by means of two handles controlling a set of gears. It drives two endless chains, carrying two grills like the grill of the waiting place. Their curved blades run through the void space left by the blades of the waiting place. Thence the projectile is seized and, pulled by the movement of the chain, is carried to the loading place, where it is put down automatically.

The loading place, placed in the upper part of the hoist framework, is composed by flat blades covered by brass and a stop for the projectile. The stop is controlled by a handle, that lowers it when the projectile must run to the thrower. In the same time it unlocks a safety lock, that stops automatically the movement of the chain, when the projectile is put down on the loading place, and blocks the movement until it is not empty.

i) The mask is composed by a thick shield made of steel, cylindrical in shape, two lateral wings, and a roof. It is bolted on the joints and the supports of the slide.


Service of the piece. – The service of the gun required four servants, two operators, and at least four shell-handlers : only three of them nevertheless need a particular training, the other can be trained in a few hours, and their action requires only good will and muscular effort.

The servants are : the aimer, the assistant aimer, the loader and the breech number.

The aimer aims and fires.

The assistant aimer operates the quick motion gear.

The loader operates the conveyor, throws the projectile, and introduces the bag cartridges.

The breech number locks and unlocks the breech, primes, and aids the loader.

The operators operates the hoist.

Two of the shell-handlers supply the hoist; the other two bring the cartridge case backwards, and give them to the loader and the breech numer.


The overall working is as follows :

Let’s suppose that the shot is fired, and the gun is returned in firing position. The loader is rolling the projectile from the supplying place to the thrower.

The assistant aimer lowers the gun in loading position. In the same time, the breech number opens the breech. When the breech is opened, the loader tilted the conveyor, that is engaged into the gun axle. With the help of the breech number, he throws the projectile, and introduces the the bag cartridges. Then he unlocks the conveyor, and brings it back to the  loading place, where he deals with the filling of the thrower. In the same time the breech number locks the breeck and primes, and the assistant aimer operates the motion gear to connect the gun with the elevating gear. When the breech number calls “ready”, the aimer, who has constantly directed the line of sight on the target, fires. As seen, it can do it only when the gun is connceted with the elevating gears, that is aimed to the target.

The gun recoils, then returns in firing position, and the loading operations restart.


Thanks to the mechanic safety devices of the gun, no mistake is possible. On the other hand, owing to the easiness of the servants duties, to the little effort required by the various loading and aiming operations, and to the independence of these operations, it is easily understandable that the speed of fire can be high. As it is said, it can attain rate of fire of 3 – 4 rounds a minute with well trained gunners. Taking account also of the great power of the gun, we have to admit that the Schneider 24 cm quick-firing gun is a weapon really very effective for the coast defence.


III. Numerical references and data


                   Main data

Calibre :

Shell weight:

Muzzle velocity :


Length of the barrel :

Length of the rifled part :

Number of the barrel grooves :

Weight of the gun with the breech-block :

Weight of the breech-block :


Height of the line of fire :

Length of the normal recoil :

Diameter at the base of the sellette :

Elevation :

Traverse :

Weight of the cradle :

Weight of the slide :

Weight of whole platform :

Weight of the bedding :

Weight of the mask :

Weight of the whole carriage :

Weight of the gun in action :

                   Ballistic data

Weight of the projectile :

Weight of the charge  :

Muzzle velocity :

Muzzle energy :


240 mm

170 kg

800 m/s


10,800 mm

8539 mm


24,500 kg

425 kg


2000 mm

650 mm

1900 mm

+ 12° / - 5° 30’


4680 kg

5590 kg

2830 kg

3000 kg

4300 kg

20,400 kg

44,900 kg


170 kg

50 kg

800 m/s

5545 t/m




This is the translation of an advertisement of the French firm Schneider-Canet published in 1908 (SCHNEIDER & CIE. Matériel de côte. Canon à tir rapide de 24 cm L/45 sur affut à berceau à pivot central), reporting the main features of the 240mm quick firing coast gun. As the booklet itself adfirms, there were some differences from the model ordered by different countries. The data reported here refer to the model orderd by Peru 1906, but are very similar to the Bulgarian model.