Seems now Wisner's is working on something too.

With all the aftermarket mags that Wisners, Brownells, Numrich, etc sell, it's odd they haven't put something on the market by now for the 541/581's. Especially, since all those 541X's hit the market from CMP.

http://www.rimfirecentral.com/forums/showthread.php?t=391325

I believe that Ma Remmy still sells the el plastico mags for these 22's. Guess the aftermarket vendors heretofore felt that was good enough for the 541/581 users. Not so.