The Saiga uses the same type of gas system that the AK series rifle uses: Long-stroke piston.
A piston is pushed by the force of the gases from the firearm when a round is discharged, and it keeps powder residue and carbon from impeding the action of the Saiga.
It is widely accepted that this type of action provides greater reliability than most other semi automatic actions.
This piston is located inside the gas tube.
As gas is siphoned into the gas tube, the gas piston is sent rearward.
While the gas piston is sent rearward, the bolt, attached to the gas piston, is unlocked from the trunion and ejects the spent casing.
When the bolt and gas piston reach the rearmost position of the receiver, the recoil spring pushes them forward again picking up a new round and chambers it, and the cycle repeats when the trigger is pulled.

Another key feature cited in the reliability of the Saiga is that the rifle is designed to have loose tolerances between moving parts.
These loose tolerances allow more space between the moving parts of the rifle, and they allow the rifle to push any dirt and debris out of the way when the action cycles.
All Saiga rifles have a hammer-forged chrome-lined barrel, which influences the Saiga's reliability by making the inside of the barrel more resilient to corrosion and enabling the rifle to withstand more rounds to be fired out of the barrel without an adverse effect on accuracy.
This allows the firearms barrel to be cleaned easier than that of a non-chrome lined bore.
The Saiga uses the same type of gas system that the AK series rifle uses: Long-stroke piston. A piston is pushed by the force of the gases from the firearm when a round is discharged, and it keeps powder residue and carbon from impeding the action of the Saiga. It is widely accepted that this type of action provides greater reliability than most other semi automatic actions. This piston is located inside the gas tube. As gas is siphoned into the gas tube, the gas piston is sent rearward. While the gas piston is sent rearward, the bolt, attached to the gas piston, is unlocked from the trunion and ejects the spent casing. When the bolt and gas piston reach the rearmost position of the receiver, the recoil spring pushes them forward again picking up a new round and chambers it, and the cycle repeats when the trigger is pulled.
Another key feature cited in the reliability of the Saiga is that the rifle is designed to have loose tolerances between moving parts. These loose tolerances allow more space between the moving parts of the rifle, and they allow the rifle to push any dirt and debris out of the way when the action cycles. All Saiga rifles have a hammer-forged chrome-lined barrel, which influences the Saiga's reliability by making the inside of the barrel more resilient to corrosion and enabling the rifle to withstand more rounds to be fired out of the barrel without an adverse effect on accuracy. This allows the firearms barrel to be cleaned easier than that of a non-chrome lined bore.
Saiga semi-automatic rifle