This measurement is something I've never heard before. Perhaps someone i.e. Rocketman can explain. Thanks.
"unmounted swing effort and mounted swing effort"
This gets into physics and Newtonian Laws- best described in Gene Hill's book Shotgunner's Notebook, and the also late, great Mike McIntosh went into it with David Trevallion in their "Shotgun Technicana"-- If you are a pragmatic shooter, as I consider myself to be, that "Machts Nicht"- if it fits and has the slight muzzle weight forward I do best with afield, then old Ike Newton can sit on his ass all day in an apple orchard and do his time studies--
