Silicone 35 air gun lubricating oil is specially prepared for airguns and air rifles, it is the only specialised oil for air guns. Use sparingly. Just a drop on a VFG felt pellet and fired through the barrel every one thousand shots.
Most manufactures of air rifles do not specify the type of oil to be used when cleaning. However, an-ordinary oil presents problems in the air rifle because of a condition known as "dieseling" (a mild explosion takes place as the oil is mixed with the air and heated by compression).
The major effect of dieseling is that, because varying degrees of ignition produce different velocities, we end up with inconsistent accuracy. Sometimes, if the barrel has been lubricated with ordinary oil, the ignition will take place in the bore as the oil is ignited by the hot air from the transfer port following the pellet along the barrel.
This will occasionally produce a jet of flame at the muzzle. Smoke is always evidence that dieseling has occurred. The answer is to use lubricant that will not ignite but which will still lubricate the piston sufficiently. This is provided by the silicone 35 oil. Use the oil sparingly.
Abbey lubricating oil comes in a handy 30ml squeeze bottle for exact application and no mess.