GreatWapiti: I disagree with you!
Maybe YOU knew it but on two different occassions several interested parties were all unaware (including me and the store owner) that the Model 77 magazines worked fine in the Model 581's.
Indeed they are plastic, but they do work!
Does someone make a metal Model 581 (or Model 77) magazine?
Anyone that BUYS a Model 581 knows they are getting a Rifle with a 5 round plastic magazine - the object of my posting was to make those same folks aware that there is a ten round option available to them in the form of the Model 77 magazine.
Hold into the wind
VarmintGuy