Try E-gunparts, Brownell's, MidWay USA, gun shows, gun shops, want ads.
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
The Revelation model R125B in .22 Long Rifle was manufactured by the Savage Arms Company. It was sold under the Revelation brand, which was a label used by the Western Auto Supply Company for firearms and ammunition. The R125B is a bolt-action rifle known for its reliability and accuracy.
30-50 yrs
It's the same as the Mossberg 321