If you need magazines Midway has them for the Nylon 77. They work very well in the 541/581 Remingtons. They are still made of plastic but work better than the originals. I ordered them for my rifles. They fit snugly with no wobble and feeding has been 100 percent.
That's good info.. Didn't know those would interchange..
BTW, here's a link to a 541S up for sale..
http://www.gunbroker.com/Auction/ViewItem.asp?Item=107681165It seems a bit, um, high... But who knows??
