go to e-gun part
100-450 or so
It is a Mossberg Model 800.
Take it to a gun smith.
The Revelation 330A series were shotguns, though some had rifled barrels, and sold by Western Auto but made by Mossberg. The 330 line was sold in the late 1960's to early 70s, without a serial number I can't tell you the exact year.
10-125 USD or so
The Revelation 22 Model R100B caliber rifle was manufactured by Mossberg. The company Western Auto Supply is known to sell both these rifles as well as the cartridges for the rifle.
Revelation model 200-2550 lever action rifle was made by the marlin firearms company.It is a Model 336 Marlin rifle.
50-100 USD
These guns were made for Western Auto Supply Co. By a different manufacturer. The closest description I could come up with is made by Stevens and is only worth about $200.00 in 100% condition. Hope this helps. I own this very rifle. The Western Auto Revelation 100 is a Mossberg 321. Parts are available from Numrich.
30-50 yrs
It's the same as the Mossberg 321