You probably have a Mk. I pistol, manufactured circa 1958. If this is the case, it would be a semi-auto pistol, chambered in .22 Long Rifle.
50-300 depending on specifics
Unaware of any maker by the name of Rugar. Ruger, however, does make a Mark II. Value range 100-200 USD
It doesn't exist. Now a RUGER, Mark 1 you can get a manual for from the company website.
To determine the age of a Ruger M77 with the serial number 78-11246, you can refer to Ruger's serial number records. The Ruger M77 was first introduced in 1968, and the serial number indicates that this particular rifle was likely manufactured in the late 1970s. Therefore, it would be approximately 45 years old as of 2023. For the most accurate dating, you may want to contact Ruger directly or consult a detailed manufacturing guide.
If the new Ruger web site is working, it has extensive sn data.
about $230
@ 4kilos
Neither, it is a Walther.
No such maker known.
50-500 usd
Yes, but, not recommended
If you mean a ruger, 100-600 depending on specifics