Article on silencer prosecutions
In the Western Criminology Review. Basically, the conclusion is that most silencer prosecutions are for simple possession; when charges involve possession in connection with crime, it's usually a drug offense. Prosecutions for use in a violent offense are almost zero.
The point he ultimately makes is that sentencing should reflect this Instead, the Federal sentencing guidelines call for two year's minimum imprisonment for first-offense possession, and if possessed in connection with crime, a separate provision mandates a 30 year, consecutive, minimum, without parole -- a sentence exceeding many jurisdiction's punishment for 2nd degree murder, and far exceeding their punishments for forcible rape.