What Year did Pietta Change Cylinder Notch Size??

[Freedom]

 I have looked a lot for this exact Year...but cannot find the Year it took place...lots of info about the different sizes, But I cannot find what Letter Code is associated with this change.
Thanks

[Fox Creek Kid]

They changed their grip as well to better fit the larger hands of today. I have a Pietta Remmy made in '75 and it is a ringer for an original in size and the smaller grip fits me better as well. 

[Sir Charles deMouton-Black]

I don't have the answer to the question - "WHEN", but here is an older discussion;

http://www.cascity.com/forumhall/index.php/topic,28843.msg379839/topicseen.html#msg379839

Maybe "Raven" knows.