How old is a Stevens model 820?

What is the model of your 16 gauge double barrel Springfield JStevens company Chicopee Falls Mass with the number 5100 stamped in the metal? What is the age and value of an Ithaca model 37 featherlight 16 ga sn 200008? Have Winchester 38-55 serial 250561 where can you buy ammo? What is the value of an Iver Johnson 25? What is the age and value of a 22 caliber J Stevens Arms Company Springfield Model 15 rifle? What is the value of a Beretta model 21A? What is the value of an Iver Johnson 38 SW pat pend aug 2596? What markings appear on older Smith and Wesson revolvers? What is the value of your Ruger 44 mag carbine semiautomatic purchased in the early 1970's? Did colt make a 1911 auto in a .32? What are the price ranges for vintage cap guns? What is the difference between the .35 Remington and the .35 Whelen? Colt cobra ser a92610 what is mfag date? Where can you find information about a 22 S-L-LR Stevens Model 75 single shot pump? What is the value of a 410 Ithaca Model M66 Supersingle lever action single shot in great shape? Winchester model 74 rifle .22 cal? What is the value of a 725 Remington in 222? Where can you find a fore stock for a Meriden single barrel shotgun? What is the cost of a Beretta-Mod 950 B-Cal 6.35 pistol made in Brazil? What rifle does michael westen use?