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.
No. a 177 is a 4.5mm pellet. A 5mm is a 20 cal pellet. A 5.5mm is a 22 cal pellet Don't try it in the wrong airgun.
The Sheridan Blue Streak air rifle uses a 5mm pellet. This is about .20 caliber- larger than the .177 pellet, smaller than the .22 pellet. I have been able to get these at Bass Pro Shop. There are also at least 3 lots of them for sale on Ebay right now. Only the 5mm/ .20 caliber pellets will work in your rifle- do not try to substitute anything else. P.S. Have had one for years. These are extremely good air rifles- very accurate, very powerful.
The Blue Book of Airguns has the info you need. Also, all Sheridan Streaks are .20 caliber, not .22 caliber.
The Blue Streak went into production in 1995 and is still produced.
It was manufactured in 1978
1974 see the link below
There are 4 different versions of the Silver Streak. Most list parts as 397. I am unable to locate any reference to part D279 1D. So here is a current drawing of the parts to a current sliver streak. Crosman has a parts list of most their airguns. Crosman owns both Benjamin and Sheridan. see the link below
You have given me all the information except the model. Sheridan has several different models at different prices
The term for an ice pellet larger than 5mm in diameter that forms during a thunderstorm is "hailstone." Hailstones are formed when updrafts in thunderstorms carry raindrops into extremely cold areas of the atmosphere where they freeze, forming layers of ice that can grow larger as they are circulated by the storm.
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
Some parts are available through Crosman (Crosman owns Benjamin and Sheridan) See the link below.
5mm :)