I believe you are asking about a Sheridan .20 cal (5mm) air rifle. They started to make this rifle in 1949 and stopped in 1990 ( sheridan sliverstreak model ) During the 1990's the name changed to C9 sliverstreak and C9 bluestreak. The value is determined by the current condition of the rifle. You did not give any such information , therefor I can not answer you.
Sheridan air rifles who is owned by Crosman Sheridans are 5mm air rifles
What is the age of a Sheridan c series 5mm 20cal rifle serial number 370862
You have given me all the information except the model. Sheridan has several different models at different prices
The Blue Book of Airguns has the info you need. Also, all Sheridan Streaks are .20 caliber, not .22 caliber.
Your rifle can be aged based on its serial number. Please see the link below.
It depends on the model, but usually it is right on the barrel or the receiver. If it is really old it may not have a serial number. For a time Benjamin and Sheridan did not serialise their rifles.
In order to give you an estimate of value, I need to know the current physical condition of the rifle. YOU need to give it some sort of rating like "Poor, Fair, Good, Very Good or Excellent condition." Without some rating it is not possible to answer you. Today Both Benjamin and Sheridan are owned by Crosman Air gun company.
Crosman air gun company owns Sheridan. Crosman offers a free service to locate shops that repair Crosman products. See the link below.
Crosman owns the Sheridan line of air guns. They offer a service to locate shops that repair older products. See this link. http://www.crosman.com/general/find-a-service-center
There are 3 versions of the Sheridan Blue Streak. See the link below for the 2nd version. BTW today Crosman owns the Sheridan and Benjamin line of air guns. This link is from Crosman
75-200 USD