About 275 in good condition
Remington's website has a history section that you can look at.
Your question answers itself.
probably 200-400 depending on condition
Best left to a qualified gunsmith.
If you look closely, I think it's a Sportsman 48 instead. Anywhere from $100-$300 depending on condition and options.
Try ebay. Runs about $10 with $3 shipping.
Check out www.corsonsbarrels.com, but looks to be around 200 to 220.
$200-$250. sales@countrygunsmith.net
The exact value of a Remington Sportsman 12 Magnum actually depends on a couple things. Some of these things would be the condition and age of the Magnum.
how much is a remington umc 12 gauge serial number 247442
Remington has made many thousands of 12 gauge shotguns in dozens of different models/configurations.