My copy of the Jeffrey"s 1930 catalog contains an illustration of the Jeffery .600 Nitro Express rifle with the following remarks:
" We recommend the Under Lever Push forward Snap Action, as shown in this illustration, for all powerful Smokeless Powder Rifles. It is a far stronger Mechanism than the Top Lever, and it admits of nearly ten times as much pressure being applied to withdraw the bolt as can be got from a Top Lever The cocking, opening of the Breech, and ejecting of the fired cartridge cases are much easier with the Under Lever Snap Action than with the Top Lever."
Can anyone explain why this action should be stronger and much easier to operate than the conventional top lever model? Are the locks cocked by opening the barrels, or by the action of the underlever, before the barrels are opened?
I directed this question to Norbert Klups, author of "The Double Rifle", but he had no explanation to offer.