never heard of them..........the old model actions like on your 58 have no transfer bar and a lower hammer...there is a notch in the hammer to prevent the hammer from hitting a live cap.....these are what most of the eaily made guns had...kinda iffy if they work at all........also check the firing pin spring to make sure it ok ..lots of these springs break and colasape with time.........to see if the notch is working try with gun open and push on hammer to see if the firing pin pushes out past the reciever?
?jb another thought.if you are worred of the firing pin hitting a cap unless you change the inside parts you will have the same problem with any cap or primer,,,,,,,how ever you can change out all the insides of you gun to new style with a transfer bar and not have to worry about it at all.........i might have all or most of the parts here.........i love the old style myself and usally change new to old to get rid of transfer bar and the high hammer,,,,,pm.me if you might want to trade internial parts...jb