what is the difference between the lyman no.56w which was an option on the m71 winchester and later in 1948 i believe a standard item and the lyman no. 56a. i have one of the 56a sights which i put on a japanese  made winchester 1895 which is factory drilled and tapped and will take receiver sights for the winchester m71. i did have a williams fp71 on it.thanks john