The Powermaster was made by Crosman corp. At best the rifle is worth $30. But if you want it repaired I suggest the you go on-line and search for "Air Gun Repair" and find someone near you to repair the rifle.
You can check www.crosman.com and look up "owners manual" at the bottom of the page to see a diagram of your rifle.
When you go to Crosman look up the service centers and give one a call thay have a seal kit for around $20 thay can send you and rebuild it yourself
See the link below for the Owners manual and Parts manual. Crosman makes the Remington air rifle.
This is known as the repeatAIR not repeater. It's the Crosman model 1008 You can find the parts diagram for all Crosman's weapons on their web page. (See the related link at the bottom of this page) then click on Rifles or Pistol manuals
see the link below for the owners manual. The Marksman Repeater is a 4.5 .177 caliber pistol not a 5.5 .22 caliber pistol.
.177 cal. Crosman, daisy, rws, beeman, marksman all make pellets in the .177 size
go to the link below.
It's in the grip. See the link below.
It was made between 1976 and 1983.
Made by who? If you are asking about a Marksman Repeater, then it is not worth much. They only cost around $20 brand new. Used they go for less that $10
Go to (See the link below) and find your parts and owners manual for your gun or rifle. Crosman keeps a web page for older airguns.
Brand new, they sell for under $25. Used they sell for around $10 - $15
Lets start with: Who made it. How old is it. Is it still working. What do you mean by "USED" Well Used or just used.
The .22 is a larger slug and will have more knockdown power than the .177.