When a gas is compressed, it is heated. When it expands, it is cooled. The gas in a PCP or CO2 gun is already compressed, so there is only cooling when it is shot and expands. In a springer, the air is rapidly compressed, resulting in very hot local temps when it is shot. It is this local gas temp that ignites the oil.
2 Mike Melick tuned up QB79
1 Mike Melick tuned down AR2078A (60 shots/CO2)
3 pistols (Daisy, Gamo and Beeman)
4 other rifles (3 old springers and Daisy target)
Crosman custom 2400KT - 18" .177