A new project of promising artillery weapons, having a number of characteristics, was created by the designers of NORINCO Corporation - the leading Chinese developer and manufacturer of weapons and equipment. The aim of the work was the creation of a new towed system of caliber 155 mm with reduced dimensions and weight, which can significantly facilitate the transportation of guns on various roads and over rough terrain. According to reports, the project AH4 was originally created taking into account the output to the international market. Thus, a new type of weapon is exclusively an export sample and is not intended for supply to the Chinese armed forces.
The existence of the project AH4 became known in 2012 year. In the middle of 2014, the first photograph of a promising weapon was published. In the photo, the howitzer was captured in a transport position on a special trailer. In November of the same year, NORINCO took part in one of the Chinese military-technical exhibitions, presenting a number of already well-known and new developments. Among other samples weapons and equipment at this exhibition for the first time publicly showed a full-fledged sample of a promising tool. In the future, the product AH4 was repeatedly demonstrated at various exhibitions and showrooms, however, until recently, the development prospects were not specified.
In mid-July last year, the development company talked about getting the required results. According to the official report of NORINCO, by the summer of 2016, all design work was completed, and all necessary tests were carried out. In addition, the production lines necessary for the production of serial guns were prepared. The assembly of serial weapons could begin at any time, immediately after receiving the corresponding order. However, at the time of publication of such News AH4 howitzer orders were not available.
From the point of view of the general concept, the Chinese NORINCO AH4 gun is often referred to as an analogue of the BAE M777 towed howitzer, which is already in serial production and is in service with several countries. At the same time, despite the similarity of ideas underlying the two projects, the samples have a lot of noticeable differences. The two guns differ both in their design and in terms of the materials used. This situation is quite understandable and explainable: the designers of two different companies had similar goals, but achieved them in different ways.
Rapid transfer of weapons to the desired firing position should be carried out with the help of a carriage with a wheel course. In order to facilitate the transportation of the howitzer in difficult conditions, a lightweight gun carriage design was developed, capable of providing the required stability during firing. At the same time, the carriage has the smallest possible size, but provides a solution to all tasks.
The basis of the AH4 gun carriage is a relatively large-sized support platform, to which all other units are attached, including the bed and the wheel course and the attachment devices of the swinging artillery unit. In front of the platform, articulated mounts are provided for the two swinging wheel balancers. When moving from a transport position to a combat position and vice versa, balancers with wheels can move up or down, lowering the platform on the ground or raising it. When moving, the hydropneumatic system responsible for the movement of the balancers performs the functions of a shock absorber, providing a soft stroke.

The first published image of the gun. Photo China-defense.blogspot.fr
On the sides of the platform, directly behind the wheels, there are protruding units, which are the basis of the front legs. The beds consist of two parts: one is an element of the platform, while the second is hinged on it. In a combat position, the movable part of the frame rotates forward and sideways. When translated into the stowed position, this device turns back and is fixed at the side of the platform. To distribute the weight of the implement to the ground, relatively small flat supports without coulters are used.
In the back of the platform there are two fixed base of the bed. In connection with some features of the layout of the carriage, these devices are located at an angle to the ground, with the rise of the rear. The bases of the beds have hinges for mounting swinging devices. Swinging units rear bed made in the form of large box-like parts, equipped with wide openers. When lowering the bedding on the ground, the coulters provide support to the ground. In addition, when transferring to a combat position, hydraulic shock absorbers must be in contact, partially damping the recoil impulse.
On the base platform of the gun carriage there is an axis for mounting the support of the artillery unit. For the implementation of the horizontal pickup is responsible U-shaped device with mounts for trunnions on the side racks. The design of the support and its drives allows you to fire in a horizontal sector of width 22,5 °. It also provides a change in elevation angles ranging from -3 ° to + 72 °. The aiming control is carried out with the help of mechanisms with hydraulic drives. Control over such processes is carried out from the console at the gunner’s workplace.
The swinging artillery part of the AH4 howitzer consists of the gun itself and a set of devices for mounting it on a gun carriage. An interesting feature of the layout of the swinging part is the shift of the trunnions as far back as possible to the level of the breech of the gun. This allows to a certain extent to simplify the vertical guidance, as well as to facilitate the construction of the mast. The connection of the gun with a carriage is carried out with the help of several transverse details-clips and longitudinal beams. The latter are in contact with the guidance mechanisms and supports.

The carriage is characterized by a simplified and lightweight design. Photo Imp-navigator.livejournal.com
The main element of the perspective howitzer is a rifled barrel caliber 155 mm long 39 caliber (6045 mm). The barrel is equipped with a developed multi-chamber muzzle brake and is sealed to the bolt group. The use of hydropneumatic recoil devices is foreseen. The breech of the gun is located between the longitudinal beams of the swinging part, which determines the specific ergonomics of the loading process.
To the left of the cannon on the rocking installation is placed the sighting equipment, which allows attacking targets both in direct fire and when firing from closed positions. The sight is placed directly above the gunner's console, which is used to monitor the operation of the pointing drives.
The promising howitzer NORINCO AH4 is said to be capable of using the entire existing range of 155-mm artillery shells of Chinese and foreign production. In particular, full compatibility with shots that meet NATO standards is ensured. Thus, the gun operator can use any available projectiles of the appropriate caliber. The type of ammunition, respectively, should be chosen based on the assigned combat missions.
Together with the "traditional" high-explosive and other projectiles, the gun is capable of using new types of ammunition. In recent years, the Chinese defense industry has developed and offered customers several new products with various features. Together with the weapon, the customer can purchase adjustable projectiles guided by satellite navigation signals or a GP6 projectile with aiming at a target illuminated by a laser. In the latter case, allegedly, the gun is capable of hitting a stationary or moving target from a distance of up to 25 km with a probability of up to 90%.

The gun in the firing position. Photo NORINCO / Janes.com
The lightweight towed howitzer AH4 has a combat weight of 4,5 tons, which allows it to be transported using various tractors. In addition, it is possible to transport military transport guns aviation. In particular, some of the existing Chinese or foreign-built helicopters can carry an external howitzer. According to published data, after arriving at the indicated position, a calculation of seven people takes no more than 3 minutes to deploy a howitzer. Transfer to a stowed position for departure from a position takes about 2 minutes. Due to the lack of own styling on the carriage, the transportation of the ammunition is assigned to transport equipment, primarily to the artillery tractor.
A characteristic feature of the new weapon is an unconventional mast design, which simplifies deployment at the firing position and reduces the mass of the howitzer while retaining other characteristics. In the combat position, the gun rests on a relatively large main platform, and additional stabilization is provided by two side supports and rear beds, equipped with shock absorbers and openers. Several points of support, including those that burrow into the ground, shock absorbers and a muzzle brake, ensure acceptable stability of the position of the howitzers during firing.
The lack of automatic loader and a relatively large mass of 155-mm separate shots imposes certain restrictions on the rate of fire, but this parameter still meets modern requirements. A trained calculation can show a firing rate up to 5 shots per minute for a short time. With prolonged firing, the rate of fire drops to 2 shots per minute.
When firing standard shells for various purposes, the maximum range of the shot reaches 25 km. This can be used as a normal "blanks" and guided projectiles. Also, Chinese specialists have recently created several new projectiles of the active-reactive type. The presence of the bottom gas generator optimizes the aerodynamics of the projectile, which allows you to get the firing range to 30 km. According to some reports, the latest Chinese active-missiles show even higher performance. Their firing range reaches 40 km, although the accuracy of hitting at such distances may deteriorate.

Howitzer in position for direct fire. Photo Defenseworld.net
The newest Chinese light howitzer NORINCO AH4 is considered to be a direct analogue of the American gun M777. Moreover, some features of the design of the two samples suggest that the Chinese gunsmiths, at least, took into account foreign experience. Thus, similar means of distributing weight and recoil to the ground were used, and a similar system for installing the tool body was used. It is known that the company BAE Systems when creating their guns actively used aluminum and titanium, which made it possible to drastically reduce the mass of the structure. Probably, the Chinese designers also used lighter materials and alloys, which made it possible to obtain the corresponding results. However, in terms of mass, the AH4 is inferior to the M777: the American gun weighs 4,2 t against 4,5 t Chinese.
From the point of view of the declared fighting qualities, a promising weapon of Chinese development is not inferior to the main foreign competitor. According to the well-known data on the capabilities of the AH4, a howitzer can send an ordinary projectile to 24 km, an active-reactive projectile to 30 km, and products of the latest models can fly to 40 km. M777 also shows similar characteristics. There should be noticeable differences.
According to the latest development company reports, the AH4 project has passed the development and testing stage. The light towed howitzer has already proven its capabilities and is now ready for the start of mass production. The project was initially developed with a view to entering the international market, which is why the People’s Liberation Army of China has not yet shown its interest in it and is unlikely to do so in the future. As for potential customers represented by foreign armies, information on their account is not yet available. During past exhibitions, third-country military showed interest in new weapons, but as far as we know, no one has yet wished to sign a firm contract for the supply of artillery.
To solve various combat missions, modern armies need weapons with various specific features. In particular, in recent years there has clearly been a tendency to increase the potential of large-caliber howitzers with the lowest possible weight. The answer to this challenge should be the newest Chinese towed system NORINCO AH4. A few months ago, the developer of this gun completed all the required work, and now accepts orders for the supply of mass-produced weapons. However, as far as is known, the prospective light howitzer has not become the subject of a contract.
On the materials of the sites:
http://janes.com/
http://china-defense.blogspot.fr/
http://globalsecurity.org/
http://warspot.ru/