Certain parts of firearms are considered essential parts under the Weapons Act. The reason is to exclude that these parts are used to manufacture unregistered firearms.

The essential parts are:

• The barrel, or gas barrel
• The breech, which is the part that closes the cartridge or cartridge chamber or the barrel to the rear before firing.
• The cartridge chamber, if it is not already part of the barrel.
• In the case of handguns, the grip or other parts of the weapon are also considered essential parts if they are intended to house the trigger mechanism.
• The combustion chamber. Combustion chambers are used in weapons that do not have a cartridge chamber, but instead burn the primer or propellant charge directly in the chamber.
• The case, that is, the component of the weapon that houses the barrel, the trigger mechanism and the breech. If the case is composed of two parts, both are essential parts.
• The barrel in revolvers

What these parts have in common is that they are essential to the functioning of the firearm.

Essential parts of firearms are equal to them. This means, for example, that if you do not have the right to acquire one of these parts, you cannot do so. If one is authorized to acquire and comes into possession of an essential part, this must be entered on the firearm ownership card.

For comparison: the magazine, for example, is not an essential part (except in the case of a revolver, because the drum is also a chamber).