Between 1969-1985. But if you contact Mossberg customer service through their website, they can narrow it down. BTW, that is an excellent rifle.
We are going to have to assume you mean a Western Field M822A rifle in .22 Magnum. These guns were made by Mossberg for Montomery Wards and are basically the same as the Mossberg 640. That model is obsolete, so perhaps you might try doing an internet search for 'Mossberg 640 Owner Manual' and see if somebody has a repro available. sales@countrygunsmith.net
The Revelation Brand was used by Western Auto for guns made by others, but sold by Western Auto. In the case of your Mdl 104A, this is a Mossberg Model 640 (nice rifle, by the way). Parts may be available thru the website for Havlin Sales, and at gunpartscorp. .
Its a Mossberg 640.
You dont deserve the gun or magazine if you call a magazine a clip.
640
60% of 640= 60% * 640= 0.6 * 640= 384
30% of 640 = 30% * 640 = 0.3 * 640 = 192
48% of 640 = 48% * 640 = 0.48 * 640 = 307.2
110% of 640= 110% * 640= 1.1 * 640= 704
85% of 640= 85% * 640= 0.85 * 640= 544
640