a) According to the degree of automation of the firing (automatic execution of certain operations during the loading of the cannon):

- fire guns with automatic firing - the cannon works until the action of the firing pin mechanism is discontinued or until the projectiles are consumed; the cannon will execute fire in series or continuous fire;

- fire guns with semi-automatic firing - the cannon works automatically during recharging, but the fire is carried out manually; the cannon will execute fire cartridge-by-cartridge (fire with fire);

- non-automatic fire guns - the loading of the cannon, the reloading of the cannon and the fire are carried out manually.

b) Depending on the size of the caliber:

- machine guns: cal. < 20 mm;

- close caliber fire guns: 20 mm ≤ cal. ≤ 60 mm;

- medium caliber fire guns: 60 mm < cal. ≤ 100 mm;

- long caliber fire guns: cal. > l00 mm.

c) Depending on the use in the battlefield:

- artillery;

- anti-aircraft artillery;

- naval artillery:

• Ship-to-ship artillery system;
• Ship-to-aircraft artillery system;
• Ground-to-ship artillery system.

The main parts of anti-aircraft artillery fire gun are:

1. The automatic device (the machine);
2. The carriage;
3. Gun sights;
4. Synchronous Transmission;
5. The platform with the bogie;
6. Ammunition;
7. Spare parts and accessories.

1. The automatic device

The automatic device is intended to support all mechanisms, to ensure automatic operation of the cannon during the shooting, and to allow the barrel to move in height at the desired angle. The automatic device is everything that moves in height. It consists of the following parts:

• Barrel;
• The breech;
• The automatic loading device;
• Cradle (mitralier's box)
• Firing mechanism;
• Manual loading mechanism of the breechblock;
• Recoil mechanism;
• Fuse adjustment device;
• The acceleration mechanism.

2. The carriage

It is intended to support and ensure the movement in direction of the automatic device, synchronous transmission, gun sights and other mechanisms that provide automatic operation of the cannon.

3. Gun sights

It ensures that the projectile meets the target in light-of-sight, for both ground and naval targets.

These can be anti-air corrector devices, for MR4 and A.A. 30, 57 mm, FERANTI, for the AA 35 mm cal. OERLIKON cannon or periscope for GEAPARD A.A. system.

4. The synchronous transmission

It is intended to automatically move the cannon in elevation and in azimuth to the position corresponding to the firing elements determined by the fire-control system (SCF).

5. The platform with the bogie

Supports the carriage with all the devices and mechanisms arranged on it, ensures that the cannon is placed in a march or battle position and allows the cannon to move.

6. Ammunition

Allows the destruction of air targets, checks the functioning of the automatic device, prepares the handouts during material training.

7. Spare parts and accessories

Provides the spare tools and parts necessary to keep the tunnel in functioning condition during maintenance operations.