It is a RUGER Model 77. That is what the M77 means. Typically the M77 is the "older" style with a tang safety, blued with walnut furniture.
Virtually impossible to determine caliber by just the serial number.
Caliber can not be determined by serial number.
Can't tell the caliber from just the serial number.
Serial numbers do not designate calibers. Look on the brrel to ID the caliber.
No way to know the caliber from just the serial number
The manufacturer is normally stamped on the firearm next to the model, caliber, and serial number.
It would be in 36 caliber or 44 caliber...
Basically impossible to do with just the serial number.
If the new Ruger site is up, it has sn data.
By model, caliber and serial number.
You will have to contact Winchester.
No. Serial numbers aer NOT UNIQUE. They are intended to be unique to a given make and model- but a gun can be rebarreled to a different caliber.