TDC stands for "Top Dead Center". A term used in engines that expresses the position where the cylinder piston is in its maximum (highest) position. In airsoft, it refers to a device that is able to continuously press (usually by means of an adjustment screw) the top of the Hop-Up breech arm to form its upper limit (TDC) without causing unwanted movement. In addition, the control is more sensitive, smoother and usually with a greater reach than with the conventional lever control.

The AirsoftPro TDC is a simple device suitable for a wide range of airsoft sniper rifles. By turning the ring, you adjust the pressure of the breech arm and adjust the trajectory of the BBs. It adjusts the Hop-Up. The device provides the user with greater precision and comfort than adjustment with a screw or lever. There are two types on offer, which differ in length, location of the set screw and the lower arc for different barrel diameters. See table below.

The TDC device is made of aluminum alloy on precision CNC machines. It has two main parts. Base and a control ring. It is placed on top of the outer barrel, just above the Hop-Up chamber. The low profile does not interfere with large-sized scopes. The TDC is not supported by most gun manufacturers and cannot be simply attached and screwed on. Therefore, during installation, it is necessary to partially disassemble the barrel, measure the position of the breech arm and drill a hole in the outer barrel exactly from above. The adjustment screw of the TDC device passes through this hole. When turning it, its length changes and raises or lowers the breech arm.

In most cases, the TDC must be glued to the top of the barrel using the superglue. The package includes an M3x10 screw, which can be used to screw the device to the chamber through the barrel. This screwing is logically better than gluing, however, only some original chambers have a threaded hole. A typical example is the chamber for MB01/04/05/06/08/13 Well. Newer AirsoftPro chambers also have this thread on their upper side and are TDC compatible.

The bubble level not only serves for a more precise installation of the device, but is also suitable for shooting. Tilting the gun to the left or right will cause the bullet to bend and therefore be less accurate. A look at the bubble level can correct this error.

Specifications:

Full metal construction
Original design
Manufactured with precision CNC machining
Rounded edges to prevent catching on the gear
Sensitive regulation (1 full turn = 0.5 mm stroke)
Adjustment ring position locking: 26 positions per turn. One position has a stroke of 0.02 mm.
Built-in bubble level
Can be screwed onto some chambers
Suitable for 27-30 mm outer barrels