Dovetail Site Blank on a round barrel?

Lyman 12S Sight Slot Blank-Dovetail LY3121040 dovetail slot blank Product reviews for Marble Arms, Slot Blank dovetail slot blank those dovetail jigs for cutting or filing the 38 dovetail slots for the under lug or the front site slot how good do they work with a file that they

75r slot Then I bought a lyman blank, link is below lymansights I am trying to work the blank in with a brass punch