Mossberg
Mossberg
Try e-gunparts.com
This Revelation rifle is actually a mossburg810 ah, Mossburg made these for Western Auto, I purchased one in 1976, I know the production run was 15 years, besides this brand they made them for Montgomery wards,
Try estate sales, on line auctions, want ads, for sale ads, garage sales, pawn shops, gun shows, gun shops, egunparts, Brownell's, MidWay USA, Shotgun News.
It depends on the condition of the firearm. The 210A was made by Mossberg model 810AH
My father-in-law just gave me his and I've been trying to find info on them. I found one on a gun auction site that went for $190 with a Bushnell scope. It is the same as a Mossberg 810AH, branded for Western Auto Supply.
Your rifle was likely made by Mossberg as their model 810. In general, these are not long range sniper rifles, but were well made, reliable hunting grade firearms. If the bore and the muzzle crown are in good shape, the rifle should be capable of better accuracy than the average shooter is capable of- an adequate 300 yard deer rifle.