Crosman owns both the Sheridan and Benjamin air gun line of products. Crosman has most all the owners and parts manuals online. You can search through them and find your model.
There are two models of the Blue Streak. The CB and the CB9
See the link below for the manuals.
Also there is a book "Blue book of airguns 9th edition" that has some more information in it.
The Sheridan Silver streak air rifle was made from 1949 up to the 1990's after that it became the Blue Streak.
The Sheridan Silver Streak air rifle with serial number 8691E was manufactured in 1970. Sheridan's production of the Silver Streak models began in the late 1940s and continued into the 1980s, with specific serial numbers indicating their production years.
what condition is the rifle in.
It was made in 1975
The Sheridan Silver Streak air rifle with the serial number 5691 G was produced in the early 1970s. Sheridan's production of the Silver Streak model began in the late 1960s, and the serial numbers indicate a manufacturing timeframe of around 1971 or 1972. For precise dating, reference materials from Sheridan or air gun collectors may provide additional context.
Model numbers from 025651 to 060550 were made in 1973. Your Sheridan rifle is 40 years old.
Here is the link to all of the manuals for Sheridan and Benjamin. Crosman owns Sheridan and Benjamin See the link below.
It was made in 1974.
It all depends on age, use, and condition of the rifle. Is it in Poor, Fair, Good, Very good or Excellent condition. Sheridan made 4 different model C series. The C Silver Streak, C9 Silver Streak, CB9 Blue Streak, and C9BP. Which one are you asking about?
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
Sheridan made several C series rifles. I assume that you are asking about the C Silver Streak. Not the C9 Sliver Streak. In order to give you an estimate I need to know the condition of the rifle. Does it still work? Does it hold air. What condition is it in? All these determine the current value.
The Blue Streak has been in production from 1995 to present. If you want more Information I suggest you contact Crosman who owns both Benjamin and Sheridan. See the link below.