Huh? I thought you were supposed to leave marks. Well, if your only source of pictures was eBay you might believe that.

Hence the term 'many sixteenths'.

 

Dennis,
Craptsman won't do when there's real, Swiss, BERGEON tools to be had.

Behold! :

 

Completing the documentary efforts:

 

Has anyone ever seen a balance like that on a 261 calibre? That version of stud holder with shock protection wasn't seen until the late 60s/early 70s era stuff.

Either that's the most advanced 261 I've ever seen... or something's afoot from a reputable seller.

 

Nothing afoot other than that weird case, and my now re-adjusted sense of history:

 

let's just fess up ... there are some things just beyond research