I'm not a expert , but most noise from springers , come from the spring being released. a good lube tune will help deaden the sound of the spring hitting and less noise. My b26 before a tune was like that, after the tune , just a dull thud sound from the spring. the term you mention is mostly for 02 guns, as 02 expands and thus the noise. it can be done, but having a device is legal , if you have the proper paper work from the Gov.