Try gun shops, pawn shops,estate sales, garage sales, for sale ads, place a want ad, Shotgun News, gun shows, egunparts.
You can try e-gunparts.com
One place to check for a magazine for an older model .22 rifle is at a pawn shop that trades guns. Another would be neighborhood yard sales.
1971-72 model
We have new 10 round magazines for that rifle. sales@countrygunsmith.net
www.e-gunparts.com
The 282 is the Winchester model 521 made for sears
find a collector i sold my sears and roebuck for 750 im sure you can get quite a bit.
We have them. gunshop@nctv.com
http://www.histandard.info/PDF/Sears%20Shotguns.pdf
the model number is #57158762 and serial number is 7621447
The sears model 6c-22 was made Winchester/ same as Winchester model#490
That is basically a Savage Model 94 as made for Sears. Stocks are widely available from internet sources.