A 12-gauge shotgun refers to the diameter of the shotgun bore, with the gauge system indicating the number of lead balls of the bore's diameter that would weigh one pound. In a 12-gauge, it takes 12 lead balls of the same diameter to equal one pound. The bore diameter of a 12-gauge shotgun is approximately 0.729 inches (18.5 mm). This gauge is one of the most popular sizes for shotguns, commonly used for hunting and sport shooting.
Basically impossible to value with what you have provided.
remington 870 12 gague
Receiver
gague
all you have to do is look up the answer on goggle and get the answer right away
1971 model.
Your winchester model 101 was made in 1966 by winchester.
Can't be answered without a detailed description of all markings, finish, condition, etc..
100-350 USD
No published sn data. Seldom more than 115 USD
14g
I'm not sure, perhaps it is... RAIN.