The spring in an air rifle is considered the same consumable as a piston cup or thrust washer. Springs are usually changed during the tuning process, or as the working resource is consumed.
- - set of screwdrivers;
- - light hammer;
- - punch;
- - clamp.
Typically, the spring in rifles of the PPS system loses its performance after 2500-3000 shots. At the same time, there is a noticeable decrease in the power of the rifle (up to 30%), due to which accuracy and destructiveness are lost. Before replacing the spring, you must select and purchase the appropriate analogue. More powerful springs of the Magnum class can be used, differing in length, wire thickness and number of turns, but the outer diameter of the spring must be equal to the nominal one.
Before replacing the spring, you will need to remove the piston mechanism from the rifle. To do this, remove the stock by unscrewing three screws. Two of them are located on the side edges of the forearm, sometimes the holes are covered with decorative overlays. The third screw is usually located in the area of the trigger guard.
When the rifle stock is removed, it is necessary to disconnect the cocking mechanism drive and the rifle barrel by unscrewing and knocking out two pins located in the barrel breech body. Then you will need to remove the trigger. It can be freely fastened in the grooves of the slot of the receiver, or be fixed with bolts or pins to the block.
The spring is fixed inside the receiver by means of a thrust washer that acts as a plug. The washer is located at the back of the box and is secured with one or two fingers. To remove them, it is necessary to rest the receiver with a washer on the floor and press down, releasing the spring tension. After that, the fingers can be squeezed out with a thin screwdriver or knocked out with a punch. In some cases, especially when replacing Magnum springs, it is wise to use a special clamp.
After the stubborn washer is removed, you will need to disengage the sear, or unscrew the spring itself. In this case, the piston body will be free and will effortlessly come out of the receiver. It should be inspected for abrasion and damage, and the condition of the cuff should be assessed.
A serviceable piston should be inserted into the receiver along with a new spring, which will need to be compressed using a clamp, or simply resting on the floor. It will not be superfluous to lubricate the inner cavity of the receiver. It is necessary to control the initial position of the thrust washer, otherwise the holes for the pins will not coincide. When the spring with the piston is pressed into the receiver, the fingers are set in place, the trigger mechanism is attached and the sear is engaged. After that, you need to install the barrel and lever arm, fix the rifle in the stock.