Switch out the front sight on your post 580 Mini-30 ranch rifle for an M14/M1A style front sight*. Internal diameter is .565". Direct replacement for the front sight*. Pop the old one off and put the new one on with the same pin* as the original. This front sight includes a ring for your M16 type bayonet.
The flat below the dovetail is .38" above the bore center-line
.64 ounces
*Some fitting may be required