Transition shouldn't have scope securing holes in receiver either. Of course under the barrel circumstances... perhaps such concern is about like trying to organize rowing teams among Titanic survivors! Still, I'd want to know that the receiver isn't 'swiss cheesed'!
Concerning an original fifties plus era Win pre '64 solder on ramp...
https://pre64win.com/collections/barrels?page=6Good luck!
John
